Oil Change Questions
10 February 2010, 03:03 PM
#61
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Sorry to come a little late to this thread, but I have just forked out £2k for an engine rebuild etc after suffering big end bearing failure on an '04 WRX PPP that had just had it's regular main dealer service at 36,000 miles.
So I can firstly testify that the problem exists.
My car has full Subaru main dealer service history from new and yet required a new crank and bearings just 200 miles after the service.
I am prepared to fully support the views of Splitpin and others on here that the sensor should be disconnected as no other explanation has been forthcoming from IM despite three letters to their Customer relations/technical people.
Clearly there is something wrong when a car such as mine can suffer such a catastrophic failure and yet nobody at Subaru/IM has offered even a suggestion as to why it should happen.
I am quite prepared to believe that there is some form of cover up going on here as they have refused to even consider my suggestion that they look at the recommended service procedure with regard to oil changes.
I have little knowledge of mechanical matters - though I feel I have learned a lot in the last couple of months - but being a journalist I become suspicious when something like this happens and there is no apparent reason.
On that basis alone, I will be ensuring that in future the crank sensor is disconnected whenever I perform an oil change, and you will note the word "I' as there is no way I will ever trust a Subaru technician again unless he is prepared to accept that sometimes the official procedures are not all that is needed to ensure the job is done correctly.
Until someone comes up with a definite and proven argument why my engine failed, my money is with Splitpin's theory. Anyone who wants to take the word of the 'Mitsubishi' sceptic is welcome to.
This has been an expensive experience for me, I feel you would all do well to avoid the same. For the sake of a couple of minutes disconnecting the sensor ask yourself if you think it is worth the risk.
Don't say you weren't warned.
So I can firstly testify that the problem exists.
My car has full Subaru main dealer service history from new and yet required a new crank and bearings just 200 miles after the service.
I am prepared to fully support the views of Splitpin and others on here that the sensor should be disconnected as no other explanation has been forthcoming from IM despite three letters to their Customer relations/technical people.
Clearly there is something wrong when a car such as mine can suffer such a catastrophic failure and yet nobody at Subaru/IM has offered even a suggestion as to why it should happen.
I am quite prepared to believe that there is some form of cover up going on here as they have refused to even consider my suggestion that they look at the recommended service procedure with regard to oil changes.
I have little knowledge of mechanical matters - though I feel I have learned a lot in the last couple of months - but being a journalist I become suspicious when something like this happens and there is no apparent reason.
On that basis alone, I will be ensuring that in future the crank sensor is disconnected whenever I perform an oil change, and you will note the word "I' as there is no way I will ever trust a Subaru technician again unless he is prepared to accept that sometimes the official procedures are not all that is needed to ensure the job is done correctly.
Until someone comes up with a definite and proven argument why my engine failed, my money is with Splitpin's theory. Anyone who wants to take the word of the 'Mitsubishi' sceptic is welcome to.
This has been an expensive experience for me, I feel you would all do well to avoid the same. For the sake of a couple of minutes disconnecting the sensor ask yourself if you think it is worth the risk.
Don't say you weren't warned.
Last edited by Hopper; 10 February 2010 at 03:20 PM.
10 February 2010, 05:07 PM
#62
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Sorry to come a little late to this thread, but I have just forked out £2k for an engine rebuild etc after suffering big end bearing failure on an '04 WRX PPP that had just had it's regular main dealer service at 36,000 miles.
So I can firstly testify that the problem exists.
My car has full Subaru main dealer service history from new and yet required a new crank and bearings just 200 miles after the service.
I am prepared to fully support the views of Splitpin and others on here that the sensor should be disconnected as no other explanation has been forthcoming from IM despite three letters to their Customer relations/technical people.
Clearly there is something wrong when a car such as mine can suffer such a catastrophic failure and yet nobody at Subaru/IM has offered even a suggestion as to why it should happen.
I am quite prepared to believe that there is some form of cover up going on here as they have refused to even consider my suggestion that they look at the recommended service procedure with regard to oil changes.
I have little knowledge of mechanical matters - though I feel I have learned a lot in the last couple of months - but being a journalist I become suspicious when something like this happens and there is no apparent reason.
On that basis alone, I will be ensuring that in future the crank sensor is disconnected whenever I perform an oil change, and you will note the word "I' as there is no way I will ever trust a Subaru technician again unless he is prepared to accept that sometimes the official procedures are not all that is needed to ensure the job is done correctly.
Until someone comes up with a definite and proven argument why my engine failed, my money is with Splitpin's theory. Anyone who wants to take the word of the 'Mitsubishi' sceptic is welcome to.
This has been an expensive experience for me, I feel you would all do well to avoid the same. For the sake of a couple of minutes disconnecting the sensor ask yourself if you think it is worth the risk.
Don't say you weren't warned.
So I can firstly testify that the problem exists.
My car has full Subaru main dealer service history from new and yet required a new crank and bearings just 200 miles after the service.
I am prepared to fully support the views of Splitpin and others on here that the sensor should be disconnected as no other explanation has been forthcoming from IM despite three letters to their Customer relations/technical people.
Clearly there is something wrong when a car such as mine can suffer such a catastrophic failure and yet nobody at Subaru/IM has offered even a suggestion as to why it should happen.
I am quite prepared to believe that there is some form of cover up going on here as they have refused to even consider my suggestion that they look at the recommended service procedure with regard to oil changes.
I have little knowledge of mechanical matters - though I feel I have learned a lot in the last couple of months - but being a journalist I become suspicious when something like this happens and there is no apparent reason.
On that basis alone, I will be ensuring that in future the crank sensor is disconnected whenever I perform an oil change, and you will note the word "I' as there is no way I will ever trust a Subaru technician again unless he is prepared to accept that sometimes the official procedures are not all that is needed to ensure the job is done correctly.
Until someone comes up with a definite and proven argument why my engine failed, my money is with Splitpin's theory. Anyone who wants to take the word of the 'Mitsubishi' sceptic is welcome to.
This has been an expensive experience for me, I feel you would all do well to avoid the same. For the sake of a couple of minutes disconnecting the sensor ask yourself if you think it is worth the risk.
Don't say you weren't warned.
well said glad youve got your car back
10 February 2010, 05:25 PM
#63
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that hopper, is much more to what i would call evidence than some of the threads in the past, typically after bearing failure the first question thats asked is when was the last oil change?
not, has the car regularly been serviced, and with good quality oil?
sorry to hear of your problems, hopefully youll get some sort of response.
i was just of the opinion that it was a jumped on band wagon, by some.
not, has the car regularly been serviced, and with good quality oil?
sorry to hear of your problems, hopefully youll get some sort of response.
i was just of the opinion that it was a jumped on band wagon, by some.
10 February 2010, 05:57 PM
#64
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Hi, after an oil change how long should it take for the oil light to go out ?,
I also disconect the sensor but before joining sn just primed the filter then started the car and the oil light always went straight out (03 sti) ,are some cars taking a lot longer than this for the oil light to go out after an oil change ?
I also disconect the sensor but before joining sn just primed the filter then started the car and the oil light always went straight out (03 sti) ,are some cars taking a lot longer than this for the oil light to go out after an oil change ?
10 February 2010, 06:44 PM
#65
I think it can take anything up to around 20secs. But you should keep cranking for short bursts until the light goes out - however long it takes! Then when it does, you're good to reconnect the crank sensor and start the engine in the normal manner...
22 February 2010, 08:00 PM
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so in summary, changing the oil too often is as bad for the engine as changing it too little? dry cranking or otherwise? someone changing every 3000 is twice as likely to cause bearing damage as someone changing every 6000?
22 February 2010, 08:05 PM
#67
Well, in pure odds terms, you are running that risk, yes.
I actually get really scared at oil change time. Last one at Zen fine - no broken engine lol. But I drove home like a granny and, rather irrationally, only gradually brought boost in to full boost over the following couple of days!!!
- that's how scared I was.
Next one due now (6000m on new engine)... at API on Saturday (at least API, too, know all about the oil change issues, so in safe hands)
I actually get really scared at oil change time. Last one at Zen fine - no broken engine lol. But I drove home like a granny and, rather irrationally, only gradually brought boost in to full boost over the following couple of days!!!
- that's how scared I was.Next one due now (6000m on new engine)... at API on Saturday (at least API, too, know all about the oil change issues, so in safe hands)
Last edited by joz8968; 22 February 2010 at 08:10 PM.
23 February 2010, 09:55 AM
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Joz,
I know how you feel mate.
Though as you say it is rather irrational provided all is done properly. And there is the rub.
My engine has been rebuilt by API and is working fine now, but I think I will forever be thinking that it could happen again as I thought that I was doing everything right all along and it still jumped up and bit me.
My third letter to IM has so far been unanswered. I think they feel that they have answered all the questions I have put to them and will do no more.
David at API warned me that I would get nothing and he was right.
I must say that I have the highest regard for him and all at API. They really seem to 'know' their Imprezas and I would recommend them to anyone.
I only wish they were nearer to where I live as I would use them for the oil change and servicing from now on.
I certainly won't be trusting the job to anyone else lightly.
The next oil change will be done by me following exactly the procedure laid out by API and fingers crossed my confidence in the car will build and it will all soon be a distant memory.
I know how you feel mate.
Though as you say it is rather irrational provided all is done properly. And there is the rub.
My engine has been rebuilt by API and is working fine now, but I think I will forever be thinking that it could happen again as I thought that I was doing everything right all along and it still jumped up and bit me.
My third letter to IM has so far been unanswered. I think they feel that they have answered all the questions I have put to them and will do no more.
David at API warned me that I would get nothing and he was right.
I must say that I have the highest regard for him and all at API. They really seem to 'know' their Imprezas and I would recommend them to anyone.
I only wish they were nearer to where I live as I would use them for the oil change and servicing from now on.
I certainly won't be trusting the job to anyone else lightly.
The next oil change will be done by me following exactly the procedure laid out by API and fingers crossed my confidence in the car will build and it will all soon be a distant memory.
23 February 2010, 10:55 AM
#70
Sorry to come a little late to this thread, but I have just forked out £2k for an engine rebuild etc after suffering big end bearing failure on an '04 WRX PPP that had just had it's regular main dealer service at 36,000 miles.
So I can firstly testify that the problem exists.
My car has full Subaru main dealer service history from new and yet required a new crank and bearings just 200 miles after the service.
I am prepared to fully support the views of Splitpin and others on here that the sensor should be disconnected as no other explanation has been forthcoming from IM despite three letters to their Customer relations/technical people.
Clearly there is something wrong when a car such as mine can suffer such a catastrophic failure and yet nobody at Subaru/IM has offered even a suggestion as to why it should happen.
I am quite prepared to believe that there is some form of cover up going on here as they have refused to even consider my suggestion that they look at the recommended service procedure with regard to oil changes.
I have little knowledge of mechanical matters - though I feel I have learned a lot in the last couple of months - but being a journalist I become suspicious when something like this happens and there is no apparent reason.
On that basis alone, I will be ensuring that in future the crank sensor is disconnected whenever I perform an oil change, and you will note the word "I' as there is no way I will ever trust a Subaru technician again unless he is prepared to accept that sometimes the official procedures are not all that is needed to ensure the job is done correctly.
Until someone comes up with a definite and proven argument why my engine failed, my money is with Splitpin's theory. Anyone who wants to take the word of the 'Mitsubishi' sceptic is welcome to.
This has been an expensive experience for me, I feel you would all do well to avoid the same. For the sake of a couple of minutes disconnecting the sensor ask yourself if you think it is worth the risk.
Don't say you weren't warned.
So I can firstly testify that the problem exists.
My car has full Subaru main dealer service history from new and yet required a new crank and bearings just 200 miles after the service.
I am prepared to fully support the views of Splitpin and others on here that the sensor should be disconnected as no other explanation has been forthcoming from IM despite three letters to their Customer relations/technical people.
Clearly there is something wrong when a car such as mine can suffer such a catastrophic failure and yet nobody at Subaru/IM has offered even a suggestion as to why it should happen.
I am quite prepared to believe that there is some form of cover up going on here as they have refused to even consider my suggestion that they look at the recommended service procedure with regard to oil changes.
I have little knowledge of mechanical matters - though I feel I have learned a lot in the last couple of months - but being a journalist I become suspicious when something like this happens and there is no apparent reason.
On that basis alone, I will be ensuring that in future the crank sensor is disconnected whenever I perform an oil change, and you will note the word "I' as there is no way I will ever trust a Subaru technician again unless he is prepared to accept that sometimes the official procedures are not all that is needed to ensure the job is done correctly.
Until someone comes up with a definite and proven argument why my engine failed, my money is with Splitpin's theory. Anyone who wants to take the word of the 'Mitsubishi' sceptic is welcome to.
This has been an expensive experience for me, I feel you would all do well to avoid the same. For the sake of a couple of minutes disconnecting the sensor ask yourself if you think it is worth the risk.
Don't say you weren't warned.
The momentary stavation is enough to finish off a worn out engine, but a good engine will not suffer consequence. The reason is with excessive bearing clearances oil is squeezed out before oil supply is restored, good bearings don't suffer such leakage so are able to maintain a protective boundry layer under light loads for longer until oil supply is resumes, oil supply is also restored quicker. If there are excessive bearing clearances, the leakage of oil from them makes it take longer for the oil pump to restore oil supply - especially the big ends (as oil has to pass through the main bearings first). I've seen it happen a number of times, and not just on Subarus either. My point being is the oil change itself is not the root cause; No doubt it will have finished off the engine, but there is also a underlying contributary fault elsewhere, or a fault earlier in the car's history that has since been rectified (for example being allowed to run low on oil at some point in the past).
If it was my car; I would want further diagnosis of that root cause. Oil pressure relief valve, oil pump cover plate, or lean fueling are the three primary causes of premature engine wear. The latter will overload bearings and cause high running temperatures, the prior two will causes reduced oil pressure, oil pump cavitation, and delayed supply of the oil upon start up after standing.
(I've discounting driving style as it would be unfair to assume anything - even a thrashed engine should last 36K. Unless heavily/badly modded or driven for excessive periods with a fueling/lubrication fault, or not adjusting oil type and change intervals to suit the driving style).
Just my 2 pence.
Last edited by ALi-B; 23 February 2010 at 11:00 AM.
23 February 2010, 11:16 AM
#71
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Ali-B; Good points, well made. BUT in our experience there is a high incidence of cars here with big end failure and of the 13 - 14 cars here now I'd bet most of them are nearly empty of fuel.
So the big end failure can add in another reason. Low fuel leading to surge, which shows as inconsistent fuel supply, which becomes lean mixture, which becomes det.
I talk to other tuners and we are all amazed at how people like Subaru [ IM ] can get away with some of the things they do with/to their customers.
If we had a car fail with big end failure soon after attention, we would work with the customer to get him a deal that sort of worked for both of us. We'd both maybe end up with a bloody nose in the fight, but no-one would be an outright loser.
We do question potential warranty claims very closely and obviously we have to take the view of what may have happened may not be our fault. Usually there is a fair position to take where there is doubt and it gets sorted. We have never said " F.O we're not interested."
Trial by forum is always uppermost in the mind of any of us traders on the forums.......
In IM [ or probably any other manufacturer's ] case. They prevaricate and obfuscate [ look it up ] and in the end the complainant goes away.
David
So the big end failure can add in another reason. Low fuel leading to surge, which shows as inconsistent fuel supply, which becomes lean mixture, which becomes det.
I talk to other tuners and we are all amazed at how people like Subaru [ IM ] can get away with some of the things they do with/to their customers.
If we had a car fail with big end failure soon after attention, we would work with the customer to get him a deal that sort of worked for both of us. We'd both maybe end up with a bloody nose in the fight, but no-one would be an outright loser.
We do question potential warranty claims very closely and obviously we have to take the view of what may have happened may not be our fault. Usually there is a fair position to take where there is doubt and it gets sorted. We have never said " F.O we're not interested."
Trial by forum is always uppermost in the mind of any of us traders on the forums.......
In IM [ or probably any other manufacturer's ] case. They prevaricate and obfuscate [ look it up ] and in the end the complainant goes away.
David
23 February 2010, 11:43 AM
#73
.I totally agree that aerated fuel (such as from running low on fuel, or a fault in or problem with the pickup, jet/syphon pump, fuel pump, filter, FPR and associated lines) causes all sorts of weird and wonderful issues; Lean running being the obvious, and we are well aware of what that leads on to.
I've suffered if first hand. Not on a Subaru in my cases, but still enough to cause inexplicable fueling issues - even with the tank over half full.
I talk to other tuners and we are all amazed at how people like Subaru [ IM ] can get away with some of the things they do with/to their customers.
Arguably the problem I have won't be noticed or questioned by 95% of people, and thats probably the crux of the issue, as there are probably countless people out there with same problem as I have, yet are blisfully unware/ignorant that it may manifest in to a total failure.The only way I can see out of this, is if my car fails totally (may take years to happen), or I strip it down and inspect at my own expense
I hate cars (sometimes)
Anyway, what is it with people who drop cars of into garages on a nearly empty tank?
I have to say it does seems common in Subaru circles as well as other low priced high peformance cars. Maybe because owners are paranoid that their car will be used for a high speed run to the chip shop. I say they need to find a more trustful garage. 
Last edited by ALi-B; 23 February 2010 at 11:52 AM.
23 February 2010, 02:28 PM
#74
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Yes, in addition to the oil change thing I will now be refilling the petrol tank before it gets below 1/4 full. Just one of the things in the 'white paper' on keeping Subaru engines healthy published by API.
I can see that my bearings may have been worn prior to failure and that the oil change and even running the car low on fuel could have contributed to that, but the oil level has never been run low.
As stated earlier in this thread, the car has been serviced my main dealers since new and regularly checked for oil level in between. And that is what still irks me now. I did everything right according to Subaru and yet this still happened after 36k miles.
That is what scares me still, and is what makes me think that Subaru (IM) need to do some more investigating and far less playing the three wise monkeys.
I can see that my bearings may have been worn prior to failure and that the oil change and even running the car low on fuel could have contributed to that, but the oil level has never been run low.
As stated earlier in this thread, the car has been serviced my main dealers since new and regularly checked for oil level in between. And that is what still irks me now. I did everything right according to Subaru and yet this still happened after 36k miles.
That is what scares me still, and is what makes me think that Subaru (IM) need to do some more investigating and far less playing the three wise monkeys.
23 February 2010, 05:02 PM
#75
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Oil pressure should be there as soon as engine is started.. if not it maybe signs of a weak oil pump etc. Best way is fill oil filter, screw on, fill up and go a tad over max, start it, let it run about 10 seconds, knock it off, check oil level, top up as required and just leave it to run on idle for 5 mins, no need to rev it like some people do. Once its warm, oil has flowed round then take it for a drive, jobs a good un. Yea its a boxer/flat 4 engine but its the same as all performance engines, people who start and rev them after like 20 seconds is what funks things up, as there could be little oil pressure to the heads/turbo due to the oil being thicker when cold. Its all down to personal choice, no 2 people will agree on one thing.
23 February 2010, 06:18 PM
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some thinks to think about definitely, the fuel thing never occurred to me, i usually refuel when my tank is empty (mainly due to the 30mile round trip for 99)...seems my grandfather was right "never let your tank go below a quarter" (although admittedly for different reasons).
23 February 2010, 08:15 PM
#77
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some thinks to think about definitely, the fuel thing never occurred to me, i usually refuel when my tank is empty (mainly due to the 30mile round trip for 99)...seems my grandfather was right "never let your tank go below a quarter" (although admittedly for different reasons).
23 February 2010, 09:03 PM
#78
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Hmmm....I only ever brim the filter. My oil light goes out within 1 second, yes 1 second of me turning the key to "Start".
20 seconds sounds an age....almost like the oil pump isn't working properly?
20 seconds sounds an age....almost like the oil pump isn't working properly?
23 February 2010, 10:21 PM
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but a good engine will not suffer consequence.
The reason is with excessive bearing clearances oil is squeezed out before oil supply is restored, good bearings don't suffer... If there are excessive bearing clearances, the leakage of oil from them makes it take longer for the oil pump to restore oil... <snip>
My point being is the oil change itself is not the root cause; No doubt it will have finished off the engine, but there is also a underlying contributary fault elsewhere, or a fault earlier in the car's history that has since been rectified (for example being allowed to run low on oil at some point in the past).
Hopper's car, having been dealer serviced and fitted only with the importer-warranted PPP, should have gone on to a ripe old age. Its early failure is, as you say, a suggestion that something was wrong, but if we rule out starvation due to oil level, or visible det damage elsewhere in the engine, what do you suggest as causal factors?
Hopper - if you're reading this, do you know what sort of evidence David found when he disassembled yours, and would you be willing for him to discuss it openly here so as to add some extra substance to the thread? Was the oil pump checked for scoring/wear/sticky PRV etc?
The reason why your oil light goes out within 1 second of the engine being started is that it's spinning at 1500rpm or so. On the starter it's running at less than a tenth of that speed - so it'll take at least 10 times as long to establish the same level of oil flow. Cranking the engine for 20 seconds is an insurance policy, no more or less.
Incidentally, while this is again as anecdotal, I change the oil in my own cars every three months - or occasionally more frequently, depending on usage, and always establish oil pressure prior to starting. Touching wood, I'm yet to experience a bearing failure while I've stripped two of my own engines in that time (for upgrades) and found them absolutely pristine internally. One of them would have undergone something like 30 oil changes at the time it was stripped.
This tends to work against the suggestion gallois made earlier that "changing the oil too often is just as bad as not doing it often enough".
Last edited by Splitpin; 23 February 2010 at 10:24 PM.
23 February 2010, 10:31 PM
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Possibly. Question is, what set that chain of failure up?
With respect, you're guessing. You may well be right, but without modelling or instrumenting the engine, you can't say so with 100% confidence exactly what happens to the oil flow in half second or so it takes for the engine to fire and establish.
You're talking theoretically here, and while what you say satisfies a level of internal logic, you're placing a lot of weight on the distinction you're drawing between "good" and "excessive" bearing clearances.
Or, for example, the cumulative effect of similar transient oil starvation causing metal to metal contact subsequent to previous dealer oil changes that were performed without any form of re-priming being attempted?
Hopper's car, having been dealer serviced and fitted only with the importer-warranted PPP, should have gone on to a ripe old age. Its early failure is, as you say, a suggestion that something was wrong, but if we rule out starvation due to oil level, or visible det damage elsewhere in the engine, what do you suggest as causal factors?
Hopper - if you're reading this, do you know what sort of evidence David found when he disassembled yours, and would you be willing for him to discuss it openly here so as to add some extra substance to the thread? Was the oil pump checked for scoring/wear/sticky PRV etc?
I don't think anyone here's suggesting it should take 20 seconds for the oil pressure light to extinguish - I've never seen it take anywhere near that long. However, if you want an explanation of why it takes longer, it should be reasonably obvious.
The reason why your oil light goes out within 1 second of the engine being started is that it's spinning at 1500rpm or so. On the starter it's running at less than a tenth of that speed - so it'll take at least 10 times as long to establish the same level of oil flow. Cranking the engine for 20 seconds is an insurance policy, no more or less.
Incidentally, while this is again as anecdotal, I change the oil in my own cars every three months - or occasionally more frequently, depending on usage, and always establish oil pressure prior to starting. Touching wood, I'm yet to experience a bearing failure while I've stripped two of my own engines in that time (for upgrades) and found them absolutely pristine internally. One of them would have undergone something like 30 oil changes at the time it was stripped.
This tends to work against the suggestion gallois made earlier that "changing the oil too often is just as bad as not doing it often enough".
With respect, you're guessing. You may well be right, but without modelling or instrumenting the engine, you can't say so with 100% confidence exactly what happens to the oil flow in half second or so it takes for the engine to fire and establish.
You're talking theoretically here, and while what you say satisfies a level of internal logic, you're placing a lot of weight on the distinction you're drawing between "good" and "excessive" bearing clearances.
Or, for example, the cumulative effect of similar transient oil starvation causing metal to metal contact subsequent to previous dealer oil changes that were performed without any form of re-priming being attempted?
Hopper's car, having been dealer serviced and fitted only with the importer-warranted PPP, should have gone on to a ripe old age. Its early failure is, as you say, a suggestion that something was wrong, but if we rule out starvation due to oil level, or visible det damage elsewhere in the engine, what do you suggest as causal factors?
Hopper - if you're reading this, do you know what sort of evidence David found when he disassembled yours, and would you be willing for him to discuss it openly here so as to add some extra substance to the thread? Was the oil pump checked for scoring/wear/sticky PRV etc?
I don't think anyone here's suggesting it should take 20 seconds for the oil pressure light to extinguish - I've never seen it take anywhere near that long. However, if you want an explanation of why it takes longer, it should be reasonably obvious.
The reason why your oil light goes out within 1 second of the engine being started is that it's spinning at 1500rpm or so. On the starter it's running at less than a tenth of that speed - so it'll take at least 10 times as long to establish the same level of oil flow. Cranking the engine for 20 seconds is an insurance policy, no more or less.
Incidentally, while this is again as anecdotal, I change the oil in my own cars every three months - or occasionally more frequently, depending on usage, and always establish oil pressure prior to starting. Touching wood, I'm yet to experience a bearing failure while I've stripped two of my own engines in that time (for upgrades) and found them absolutely pristine internally. One of them would have undergone something like 30 oil changes at the time it was stripped.
This tends to work against the suggestion gallois made earlier that "changing the oil too often is just as bad as not doing it often enough".
23 February 2010, 10:42 PM
#83
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I can see that my bearings may have been worn prior to failure and that the oil change and even running the car low on fuel could have contributed to that, but the oil level has never been run low... That is what scares me still, and is what makes me think that Subaru (IM) need to do some more investigating and far less playing the three wise monkeys.
You've only got to look at Toyota's current travails to see why the consequences of even a trifling little production error can cost many millions. Why go out of your way to look for something you don't want to find?
It wouldn't be too difficult to instrument an EJ20 out with a couple of dozen pressure transducers in various critical parts of its oil system and do some proper research as to what happens when the sump and filter are emptied, but someone'd still have to front up the costs involved in that research. FHI and IM have no pressing reason to do so as it's a no-win situation for them.
23 February 2010, 10:53 PM
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It's clearly not a myth. It stands to reason that any interruption in fuel flow/pressure while the engine is under boost is going to cause transient leaning of the mixture and could cause det. Ditto driving round with a failing airflow sensor.
As Ali says it's one of a range of potential contributing factors, and it's usually pretty difficult for anyone to tell, in a roadcar environment, precisely what chain of factors is responsible for an engine failure after the fact.
As Ali says it's one of a range of potential contributing factors, and it's usually pretty difficult for anyone to tell, in a roadcar environment, precisely what chain of factors is responsible for an engine failure after the fact.
23 February 2010, 10:57 PM
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It may also be worth mentioning that with the flat four engine, the crankshaft does not get any "splash" or immersion from the oil in the sump to assist with lubrication as most upright types of engine do.
23 February 2010, 11:22 PM
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It's clearly not a myth. It stands to reason that any interruption in fuel flow/pressure while the engine is under boost is going to cause transient leaning of the mixture and could cause det. Ditto driving round with a failing airflow sensor.
As Ali says it's one of a range of potential contributing factors, and it's usually pretty difficult for anyone to tell, in a roadcar environment, precisely what chain of factors is responsible for an engine failure after the fact.
As Ali says it's one of a range of potential contributing factors, and it's usually pretty difficult for anyone to tell, in a roadcar environment, precisely what chain of factors is responsible for an engine failure after the fact.
got a forge dv on it and a prodrive backbox find it very hard tu get the dumpvalve to work when puttin in gear 3rd dont hear the turbo spool up either regularly either is it because the ecu has put me in economy mode sorry old timer
23 February 2010, 11:57 PM
#88
eggy and ste, I'm going to APi on Sat to have a few things done inc. oil/filter (GULP!) and new front discs.
I requested that Dave leave me the oil change procedure, etc bumph for me to take away with me. If I remember to come away with it lol, then I'll scan it in and send you a multi-page PDF file of it........
I requested that Dave leave me the oil change procedure, etc bumph for me to take away with me. If I remember to come away with it lol, then I'll scan it in and send you a multi-page PDF file of it........
Last edited by joz8968; 24 February 2010 at 12:00 AM.
24 February 2010, 12:02 AM
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find it very hard tu get the dumpvalve to work when puttin in gear 3rd dont hear the turbo spool up either regularly either is it because the ecu has put me in economy mode sorry old timer
24 February 2010, 12:13 AM
#90
Of course, it goes without saying. Bear in mind that it may be just one contributary factor, or a number of seperate factors that when combined lead to a failure.
On that premise, you're guessing as well. We can both guess all day long, yet both our conclusions no matter how well thought out or justified will be discredited by IM and Subaru because of that.
Simple logic would say a good bearing is within manufacturer's given tolerances, a bad or or excessive clearance is one outside of that. Having personally stripped down apparent "good" engines that didn't knock or rattle, yet found them to have bearing wear well outside of tolerance does suggest to me that its quite plausible to drive the car daily and the driver not be aware of the engine's worn condition.
Of course, assuming the problem is there from new. But it could be something that arises part way through the car's life, where oil changes from that point onwards causes oil starvation issues.
Say for a theoretical example; A dodgy o-ring on the oil pickup. The first five oil changes it was ok, but on the sixth oil change it fails, so upon start-up it sucks up air, the pump cavitates and take longer to prime, and it does this for every subsequent oil change, bearing clearances get larger and larger, the oil pump struggles more and more to restore supply until the engine eventually fails. What is the prime fault? - the oil change or the o-ring?
Either way its plausible but still not proven fact. As you say, it needs to be shown under laboratory test conditions to be conclusive
Here's an anecdote you might like: I know of a car that sometimes takes up to 10 seconds of running to build up oil pressure. Its a 15 year old BMW 528 with a leaky filter housing anti-drain valve. After standing over the weekend it has to completely fill up the oil filter housing on start up. The sound it makes is obvious that there is no oil supply. Its not my car (If it were I'd have fixed it by now ). But despite being in this state for years, its still running. I'm amazed; I've even got a audio clip of it starting cold after being left for one night (about 5 seconds of knocking before oil pressure starts to build) - it does this every morning: http://www.nataz.pwp.blueyonder.co.u...28%20knock.mp3
I can imagine that this engine will eventually fail - probably shortly after being serviced (on the bright side, the Vanos doesn't rattle).
With respect, you're guessing. You may well be right, but without modelling or instrumenting the engine, you can't say so with 100% confidence exactly what happens to the oil flow in half second or so it takes for the engine to fire and establish.
You're talking theoretically here, and while what you say satisfies a level of internal logic, you're placing a lot of weight on the distinction you're drawing between "good" and "excessive" bearing clearances.
Or, for example, the cumulative effect of similar transient oil starvation causing metal to metal contact subsequent to previous dealer oil changes that were performed without any form of re-priming being attempted?
Say for a theoretical example; A dodgy o-ring on the oil pickup. The first five oil changes it was ok, but on the sixth oil change it fails, so upon start-up it sucks up air, the pump cavitates and take longer to prime, and it does this for every subsequent oil change, bearing clearances get larger and larger, the oil pump struggles more and more to restore supply until the engine eventually fails. What is the prime fault? - the oil change or the o-ring?
Either way its plausible but still not proven fact. As you say, it needs to be shown under laboratory test conditions to be conclusive
I don't think anyone here's suggesting it should take 20 seconds for the oil pressure light to extinguish - I've never seen it take anywhere near that long. However, if you want an explanation of why it takes longer, it should be reasonably obvious.
). But despite being in this state for years, its still running. I'm amazed; I've even got a audio clip of it starting cold after being left for one night (about 5 seconds of knocking before oil pressure starts to build) - it does this every morning: http://www.nataz.pwp.blueyonder.co.u...28%20knock.mp3I can imagine that this engine will eventually fail - probably shortly after being serviced (on the bright side, the Vanos doesn't rattle).
Last edited by ALi-B; 24 February 2010 at 12:16 AM.