fastfrank

Greasemonkey,

By the mention of the CEL event I presume you are referring to a condition of the ECU?

When I dropped my oil without crank sensor intervention I never had any issues with the oil pressure light remaining on. I made the assumption all was ok. No problems since.

F

greasemonkey

CEL stands for check engine light. I was saying that removing the crank sensor and turning the engine over on a new age car will probably cause the CEL to light up. However, as mentioned, it goes out again after five successful starts, so no big deal in itself.

Only time it might be of import would be if you had the car serviced, dealer put it on a Select Monitor, and came back with a faulty crank sensor code. Last thing you want is the dealer trying to bill you for a new sensor when there's nowt wrong with the old one.

fastfrank

Thanks Greasemonkey, useful information.

As long as the car is under warranty I have no fear of being charged for any faulty components.

Eagle7

sounds like a stupid question and it probably is but dont you need a new sump plug every time you change the oil and if so where can i get one and is there a part number etc...?

in fact while i'm at it wheres the best place to get a replacement filter?

My local dealer isnt quite so local so are there alternatives or do i just have to ring up the parts guy there?

cheers

tmo

No just change the washer

Markyboy uk

I did my 1st oil change a couple of weeks ago.
Oil filter from dealer was only £4.95 (I know!, can you believe it ) and washer was 79 pence.

p1doc

stan palmers yesterday £54 oil,filter and ecu reset spot on
martin

scoobyboy

can someone explain why it only seems to be turbo imprezas that seem to suffer with this problem and not any other subaru? despite them having pretty much the same parts?

scoobyboy1

iTrader: (16)

Thought id save a few quid and changed the oil and oil filter on my car myself ,didnt reliase it was a right ******* to get the filter of, thought i could get it off without the chain, next time ill pay someone else to do it.

kend

Showells of Stourbridge, £45 for oil and filter change last friday.

Moray

Hooray at last someone brave enough to say it and I am a qualified mechanic. Couldnt agree more mate.

Gear Head

iTrader: (2)

I dont get this whole crank sensor thing. When you change th oil and start up, there is no substantial load on the engine and the cylinders and liners will already have a film of oil on them wont they??? Just a thought

Sprint Chief

"Subaru bearings are half the width of a normal in line engine"

Hmm so an engine with two cylinder banks has bearings half the size of an engine with one cylinder bank - shock horror! Doesn't seem to cause a problem on another V - configuration of flat-configuration engine I know of, and doesn't sound like a particularly great engineering challenge to be honest. Perhaps Subaru just can't design engines

If the failure was oil pressure related wouldn't the bearing furthest from the oil pump be the most likely to fail (or show the greatest wear)? Strange how it always seems to be nos 2 and 3 though... oh yes, those are the cylinders that run most lean as well aren't they? What a coincidence!

Perhaps a more likely explanation is that the oil change results in simply bringing an existing problem to the fore, and the oil change is symptomatic rather than causal? Just conjecture...

But we humans are a superstitious bunch, so keep touching wood, throwing salt over your shoulder and cranking your impreza without sensors or plugs after each oil change - may not affect anything, but it makes us all feel better

Gear Head

iTrader: (2)

Couldnt have put it better myself!!!

billythekid

This thread has come on a bit lol.

Oil is funny stuff, I know someone who works in F1 and they even control the temp of the oil as they fill the engine. All very odd.

Any way, I cant see the harm in cranking for 10 seconds to get pressure and make sure the filter is def ok and full before you fire up,

Like I said before, I dont see any point in removing the plugs, esp in the scoob as its a PITA.

Granby

iTrader: (5)

Can anyone tell me when it's best to change from semi synthetic to fully synthetic oil.

micared

Change from semi to fully at 7500k. And for the others who still don't understand why you should spin the motor with the crank sensor disconnected during an oil change , do a search, ffs. The problems you are storing up by not doing this are well documented on here by people who either have suffered the ( expensive ) consequences of not bothering, or others who know a great deal more on the subject than the rest of us, because they've made it their business to. Do you really think that people like A.P.I David have nothing better to do than publicly condone procedures that aren't necessary?........even the dealers are supposed to have had a directive from I.M. detailing the procedure.

Granby

iTrader: (5)

Thanks for that, not quite there yet

Adam M

what a bunch of stupid comments!

what kind of a fool dismisses advice which can do no harm on the basis that other cars have been fine therefore it must be a waste of time to exercise caution!

How many of these others cars for which people don't bother with this procedure are famous for throwing big ends after oil changes.

Does no one recall the big end bearing thread? the research callated by bob rawle to enable us to figure out why the engien is so prone to big end failures? we never concluded anything, apart from that there seem to be a correlation bewteen failure and recent oil change.

All these people who say, I am a mechanic and it is fine, tell me, how long does it take to generate oil pressure after you have drained the oil? The answer is quite a few revs.

In that time I would rather do my best to reduce the amount of work the oil has to do as there is no guaranatee that the residual oil film from the old oil will be replenished when the pressure from the con rod pushes against the bearing and squeezes it out.

So, we disconnect the crank position sensor to stop it firing. I think the extra vigilence of loosening plugs is also a great idea. No plus = no compression which means no load until the system is full of oil to replenish the bearings.

Other boxer engines are less prone to failure as unlike subaru they didn't do their utmost to reduce bearing length. Smaller bearing length means smaller oil film area, meaning greater pressure on the oil surface squeezing it out.

The procedure doesn't bother me as I have followed pats advice and installed an oil primer pump which makes sure I have oil pressure before I turn the key everytime I start the engine.

I think it is very irresponsible for those who by the sound of it haven't given it enough thought to dismiss such precautions, just because they haven't been unlucky enough yet to suffer the fate that many others have.

pslewis

Well, maybe - as the dealers have been told to do the job like an old woman - thats why a simple Oil Change costs so much at a main dealer!!

I feel like I am getting real value for money now, no more complaining from me (in fact, I think I will buy them all a crate of beer next time, taking such a long time dedicated to my oil change)

And here's me thinking that just spinning an engine over on the starter does more damage than getting the thing moving in the way it was designed to do!

Maybe I'm just a really stupid Design Engineer but I cannot ever remember an engine design that goes BANG after an oil change just because a man has changed the oil and not an old woman

Pete

sparkykev

I asked the dealer i bought my filter from if they disconnect any sensors etc, and he said all they do is pre-fill the filter, and not to worry as they've never had any problems arise. This i might add was for a new age, i didn't ask about a classic.

Sprint Chief

Hmm, keep the toys in the pram folks, as I said, my statements were conjecture, not fact, nor were they stupid comments, although I guess you may not have been referring to my post.

As you point out later in your post, you likewise have nothing more than conjecture to claim that the procedure is necessary.

My observations are based on a little more than just comparing to "what works for other cars", it also relates to the statistics and mode of the failure specific to the Impreza.

There is no reason for the residual oil to be "squeezed out" during cranking - unless the bearing is already worn, which is my point, that the oil change "problem" could be symptomatic of another existing problem, not causal. I suspect this concept reflects the statistics of the failures more accurately as well.

Are you sure about that? Which other designs have you assessed and carried out load calculations for? Hydrodynamic action "squeezes" the oil for sure, but why should it "squeeze out" the oil in a bearing which has not been worn out of tolerance? If the oil did "squeeze out" under pressure then hydrodynamic effects would not occur at any time, cranking or running!

NB: I am not a mechanic, and no offence intended to mechanics on this forum - they do a good job and one that I couldn't do - but I would not take the advice of a mechanic in this case, I would ask an engineer.

Diesel

Hmm just did an oil service on my 99 STi V - none of that; just headed straight for the filter

Edit to say I wore an aubergine head-scarf to fill the filter with oil whilst singing an old Vera Lynn classic. It only took about 25" for the oil pressure light to go off (inclucing telling off the kids next door) I'll try a different colour headscarf next time to see if I can get pressure at 20". You lot!

micared

When there is so much conjecture and confusion about the rights and wrongs of oil change methods, why take unnecessary risks? Prefilling the filter only takes the hour that some halfwit suggested earlier if you pour in a thimblefull at a time, and aim it through the eye of a needle. If you keep topping it up as you dismantle the car and drop the oil/remove the old filter, it's ready to go on when you need it......where's the inconvenience? People only suggest doing all of this because there is evidence that if you don't bother, you'll be back on here asking advice from the very people you're calling 'old women'!

Sprint Chief

Umm conjecture is a natural part of the engineering process, it is all about learning how things work and making them more efficient. Of course we could stop questioning things and all just follow the herd like sheep, although I suspect that if we were all like that we would still probably be living in caves hitting animals over the head for a living.

In addition filling the filter prior to fitting is a sensible idea. I never said it wasn't. Funnily enough, it probably offers little or no additional protection to your big end bearings as the big end bearings are capable of generating their own pressure. However, filling the filter will afford additional protection to many other components in the engine that are not capable of generating their own oil pressure.

However I am yet to be convinced that it is necessary to remove the spark plugs or crank the engine with disconnected sensors. I'm just discussing it in an open forum and giving my opinions - perhaps I was mistaken, I thought that is what scoobynet is all about?

If you are happy to be in the dark, as I mentioned earlier, just go ahead and do it, and if you like touching wood after pointing out something hasn't happened then go ahead and do that too - it is easy to do and not doing it might just be an "unnecessary risk". But for the rest of us, we will continue to ask questions.

micared

And while you're asking questions, which is a byproduct of not yet knowing whether you're right or not, you still don't take the suggested precautions? And you still choose to belittle those who do? Think you'll find, if you bother to do a search, as I suggested earlier, that there are a couple of respected engineers on here who have posted their findings. You must just like asking questions, because people like Bob Rawle, A.P.I. David and Greasemonkey are all known to have specific experience of Subaru engines shortcomings. Clearly, you haven't read about these. By all means, do what you want with your own engine, it's your risk, but suggesting that others don't practice the suggested 'safe' oil change procedure before you've proven it to be overkill is a bit previous.
I know the advantages of pre-filling the filter, thanks...that's why I condone it. I've also stated on here in a previous thread that I don't remove the plugs on my own car, as I believe that it's more ' safety ' than I require.....however, others do this, and I understand why. I also think there is merit in spinning the engine over with the crank sensor disconnected. That's my decision, based on information gathered from this forum from respected members, who, I suspect, are likely to have more experience of the Subaru engine, and hence more relevant info on the subject at hand, than you.
Don't recall ever suggesting that it wasn't an open forum, and that you shouldn't post your opinions, btw.......doesn't mean I'm going to agree with you though!

billythekid

My 5ps worth, the cranking, IMHO is to ensure that the air in the filter is removed from the system and that anyone who forgets to fill the filter will not have a problem.

If you drop the oil out of your sump, then re-fill and start up the effect on the bearings will be no different to starting the car after its sat idle overnight.

All IMHO of course.

micared

.......except, of course that by draining the oil, you've also drained the oil pick up pipe, which would not be drained by just leaving the car stood overnight. Therefore, less immediate oil pressure, therefore more stress on the bearings when you've done an oil change.
The cranking is to ensure oil pressure is there when you do actually start the car.......nothing to do with purging the air from the filter. You pre-fill the filter to do that.

Sprint Chief

I own a UK car and let the dealer handle it. I don't need to worry myself.

My posts contain a degree of banter, but I didn't describe anybody's comments as stupid or the posters as fools, which are contained in Adam M's post. To be fair, I don't know if they were directed at me, but I would say my posts are far more moderate than either yours or Adams. (I, for example, have yet to call anyone a halfwit)

Actually, it is evidence from API Davids post on another thread that leads me to believe that the oil change is more symptomatic than causal. I have been on here a while, as you will see from my post count. Secondly, I would value these people replying to my comments if they are interested in exploring my opinions; if they don't, then that is fine too.

What, let Subaru work on it

I didn't tell people not to practice the suggested procedure, I am questioning the engineering rationale behind it. Don't confuse the two. Anybody who takes a strangers advice on an internet forum deserves everything they get. Anyone who is willing to listen and stimulate intellectual debate on the subject can only do good surely? Why are you so defensive about preventing a qualified engineer adding his opinions on the topic?

Ummm... so you're opinions are the same as mine then... (although we have different engineering rationale leading us to these conclusions). What was your point again?

I understand why as well - they don't understand the engineering principles and are erring on safety. But if the oil change is symptomatic and not causal wouldn't it be *a good thing* to understand the cause? Just a hypothesis.

Your decision is yours and that is fine. If you disagree with my opinion that is fine too. If you disagree with my opinion and have sound engineering reasons why I would love to hear them. If someone else disagrees with my opinion please let them speak for themselves. These people may have specific experience with Subaru engines, which is valuable, but a common aspect I have found in engineering is people working close to the coal face often can't see the wood for the trees and an independent outside view can introduce new ideas.

Engineers on the board will sympathise with this point even if you don't.

MGJohn

What an interesting thread .... and quite a long one too ...Oh er Matron..

One comment I really found of interest and it will serve as a possible warning to the over zealous engine oil drainer such as myself on one particular occasion.

That comment:

>>.......except, of course that by draining the oil, you've also drained the oil pick up pipe<<

Not necessarily so. If this was the case, you'd have an air lock in the pick up which would then not pick up the oil! However, on one occasion, this air-lock in the pickup DID happen to my MG Montego Turbo following a DIY oil flush and change.

Oh yes, and I ALWAYS prime the new oil filter fully by topping up until no more will enter - doesn't take very long if as someone already suggested, you top up in between other parts of the oil change process.

On the recommendation of someone far more experienced than me on such matters, I ran my 17 year old MG Montego Turbo for 7-800 miles using Diesel Turbo engine oil instead of say a Wynns type engine flush. This to enable the longer slower acting detergents present in turbo diesel oil to give the aged engine internals a thorough flushing. Here I add that this turbo diesel engine flush treatment was REALLY effective in my turbo cars as I've used the treatment on other cars since.

However, on that first 'flushing' occasion, zealously anxious to rid my engine of every last drop of turbo diesel after the rest was already drained, I turned the engine over without plugs for a few seconds to pump out the last remnants of the now contaminated (after all those slow acting detergents had done the job well) turbo diesel lubricant. This worked a treat but, big mistake, it also cleared the oil pick up pipe of oil. So when the fresh and expensive 10-40 went in, the oil pressure light would NOT extinguish on engine start up with the new stuff. The pump was NOT picking up via the pick up....

Big Problem. Pushed car back into garage and used another car for a few days whilst pondering the best course of action. Even put up a thread about it on Rovertech.net and MGcars.org MG BBS. Lots of suggestions how to deal from partial engine strip to pack oil pump with Vaseline to standing car on steep slope at an angle to allow oil to make some entry into the pickup and thus enter the oil pump. Didn't try any of this stuff. After a couple of days of thought, had a brainwave.... tried to start car and started immediately but soon switched off as oil pressure warning light would still not extinguish! So, removed oil filler cap and placed upsidedown on top of the oil filler tube a clean empty 6 pint plastic supermarket milk bottle. Lowered the drivers window, reached through and switched on. Allowed a second or two for the fuel pump to prime the system and then started car watching oil pressure warning light like a hawk - still stayed on so two seconds later, moved smartly to front of car and clapped both hands hard on either side of the plastic milk bottle. The idea being to send a 'pulse' of higher air pressure down into the sump and force fresh oil up the pick up pipe. Soon after I peered in through the drivers open window to observe the warning lights on the instrument panel. The oil pressure warning light was no longer on .....

Apart from that minor fiasco, my car really benefitted from that 7-800 miles with the diesel turbo engine oil in it. The filth that came out on that first drain was proof enough but there were other benefits too. After 2-3000 miles with the fresh 10-40 following the treatment, the engine oil was still relatively clean and clear thus free of contaminents. I've not observed this with any car before except new ones during the first few oil changes and then only occasionally. Additionally, the engine appeared to make less mechanical noises on cold start and these would almost disappear once fully warmed up. Engine was smoother with better throttle response too. Plus, the car recorded the highest indicated speed I've seen on it and it gets up there more quickly too.

Delighted with the results of this first engine flush using Diesel Turbo engine oil, I did the same for my Tomcat turbo and other Montego Turbo with similar pleasing outcome.

Please don't take this as a panacea for any Turbo charged car with a few miles on the clock thus having plenty of muck residue lurking inside that engine. It certainly worked for my MGs and Rover turbos but, possibly for many reasons, may not do so for the more highly stressed Subaru Turbos, unless others more experienced than I know otherwise.