Oil Change Questions
 

Is it ok just to fill the new oil filter,fit to engine, then fill up with rest of oil and start her up straight away or do you turn it over with a sensor disconnected:wonder:
If so what sensor and how?

Thanks in advance.

crank sensor, its underneath alternator, just disconnect it, turn engine over untill oil light on dash goes out. re connect and start it up

I just fill oil filter and fill the engine up, job done.

correct bud ,no fafin about with crank sensors
just fill the filter then the sump and start
you will have oil pressure asap quicker than cranking
done hundreds of these with no comebacks
geo:thumb:

Here we go again.................

Agreed!!

I cannot see why a Subaru engine would be different to any other. Especially when I think of the V8 diesel generators I work on.

lol this could prob go on forever

i put mine in to a garage today, its is a mitsubishi specialist but i think origionated from scoobs

he told me all the storeis of bottom ends going after oil changes were nonsense,

but it scares me enough into doing it as suggested, lol

like anything else on the tinternet there is a whole load of b8ll**** spouted

just have to pick through it - and tbh it usually comes with experience'

have you newage imprezas especialy 03 models do fail if you keep in touchwith the forum you would know :( i wudnt get my engine oil changed if i thought that this practice was being used:( money making machine by subaru and yourself crank sensor has gt tu be dissconnected and cranked over several times or else tradgedy and a 3k bill:thumb:

It ultimately cannot be 'proved' unless someone with a lot of money/patience undergoes testing.

But whilst it does seems to be a coincidence of engines failing either hours/days/weeks/months after an oil change, then for the 5 mins extra it takes to do it the 'anal' way, I'm, personally, not taking any chances! Weigh up the equation:-

5 mins of your time?... or... a possible related(?) big end failure and a 2.5+k rebuild + time off the road? Go figure.

But hey, we're all different.

After all, whether you're in denial about the method, or not, you CAN'T argue with the physics that says, with the engine sparking, then the big ends are being subjected to huge forces when there's combuston going on, than if there was NO combustion!

i think its a load of shat all this the tdc has to be disconnected or it's game over for the engine.

That comment comes from the experience of do hundreds and hundreds of oil changes all be it on many makes and model but that includes scoobs, never once have i seen an issue.

That said for the few seconds it takes to do it, on my own car i would disconnect it, so as not to tempt fait.

The search button will reveal all - proposed (logically sound) scientific reasons for the 'coincidental failures' from the specialists (a long-time established, well respected one at that!...).

I'm done on this subject.

I think the best cause of action is to ban all oil related threads.

Hmmm. So this chap is trying to suggest that the repeated anecdotal stories on here involving cars suffering bearing failure shortly after oil changes are... works of fiction???


Don't think you'll see many people saying that it's definitely "game over for the engine". My own preferred way of putting it is that removing the crank position sensor is a sensible step because it can effectively remove a potential cause of failure.

:)

Grief, it's always the illiterate ones... :Whatever_

You will indeed get oil pressure a little quicker if you just start it than you will via cranking. The problem with your logic is that doing it this way will likely give you combustion before oil pressure, which is where the problems seem to start.

If you crank it first, you know you will have good oil supply and pressure before exposing the engine to combustion forces.

Morfo: As Joz suggests, use the search, although you could learn a lot from the fact that there's a poster on this thread who's happy enough to write on an internet forum that this crank sensor removal thing is "sh*t", but, when it really matters, does it anyway.

Bottom line is that it costs you a few seconds, does no harm, and has the potential to save you a lot of hassle and money.

Quote:
Originally Posted by jef
he told me all the storeis of bottom ends going after oil changes were nonsense

Hmmm. So this chap is trying to suggest that the repeated anecdotal stories on here involving cars suffering bearing failure shortly after oil changes are... works of fiction???

effectivey yes tht is what he was saying

he is the owner of a fairly large. evo/subaru tuning garage - for 10+plus years, altho now more evo orientated - effectivley told me i was talking p*sh when i asked if he could do that.

however id dont belive everything tuners tells me all the time - ad like i said, when doing my own oil chaanges - ill disconnect the sensor

To Splitpin and the other like minded individuals.
I'll remove the crank position sensor as suggested.
I did search the forum and as above the method to do the oil change is split.
Theres nothing wrong with spending that little extra time on your pride and joy.
Cheers

Another question.
As I will be doing the spark plugs as well. Could I just leave these disconnected when turing the engine over after the oil change?

ideally youd turnt he engine over with no spark plugs in it, then you get even less pressure on bearings

but still disconnect the crank sensor as they will still spray feul into the cylinder if you dont

someone correct me if im wrong.

well i must say ive never bothered to crank and engine but i might well do now so whrre the hell is this crank sensor is it int he midlle of the cam belt case or to the right as you look at the block

Jef, you're right. With the plugs removed, then, even the small compression on just the starter is further alleviated through the plug holes - so even better!

So morfo, if you're doing the plugs at the same time, defo whip 'em out first, before disconnecting the crank sensor and spinning the engine.


happydude - yep as you face the front of the car, just below the alternator on the block's top surface, obviously right in line with the central crank pully. It's a little sensor plug held in place with, I think, a small hex bolt...

ok cheers dude ive just been outside thou and its that cold i think i may wait till next week end, brass monkeys, the wind is blowing down my drive way like its a wind tunnel

There are two separate points there.

First of all, if you are doing the plugs anyway, the best time to do the cranking is exactly as Joz said - while the plugs are out, as you'll take even more load off the bearings (and the starter motor).

The second point though is that even with the plugs disconnected or out completely you should still disconnect the crank sensor. The reason for this is that without unplugging it, as Jef says the ECU will still inject fuel into the cylinders and will still try and fire the coils, which is less than ideal. Unplug the sensor and you'll stop both happening.

Thanks again to Joz and Splitpin.
If in doubt ask. I did.
Cheers

a statement made from many years experience working as a master technician.It was aimed at the people on here who claim it must be done(and there are many of them) or engine damage will be caused.

This simply isn't true.

However i do agree that as it does no harm disconnecting the tdc sensor and because its so easy to do then why not. if this sensor wasn't so easily accessible then i wouldn't bother.

A bold statement. How can you be 100% sure that's the case?

i have been a qualified mechanic for nearly 20 years and now work on dropps/bedfords and land rovers etc in the army and have always just chucked the oil in and away you go but for the sake of a few seconds i disconnect the crank sesnor when doing my scoob as you never know.

experience fella.

i don't think it's a bold statement.

I'm not saying that bad workmanship has never caused problems after a oil and filter change

what i am saying is if you don't disconnect the tdc you are not guaranteed that your big ends will fail

Oh I agree with that - after all there would hardly be any Scoobs on the road! :lol1:


But there certainly have been many cases where, coincidenatlly, bottom ends have failed soon after the oil change where the crank sensor has NOT been disconnected. Now it could be pure coincidence and the big end would have gone anyway... But I, and many others, think that it's too coincidental for it not to be a factor in these failures...

With no slight to yourself intended, I've met a few master technicians who are as thick as the proverbial two short lengths of wood. The chap at my local Subaru dealership is a case in point. Nice bloke, and on the case for most normal jobs, but a bit useless when it comes to anything that isn't directly covered in a service manual or update bulletin. Common sense obviously an optional extra.

One of the difficulties with "occasional" problems like this is that it's highly likely that individual dealers will see enough of them, or think about the circumstances enough to notice patterns. Online forums like this are probably the most likely method by which common denominators will start to make themselves obvious, thanks to the large user base.

Even if some dealers are privately noting it, and even if they tell IM, it's a pretty major thing for a manufacturer or importer to acknowledge and make a significant change to the service procedure on an engine family two decades old. It could (especially in the USA) open the floodgates to all sorts of legal consequences as it could be interpreted as an admission of the existence of a fault. Cue class actions and feck nose what else.

I dare say that if you could wind the clock back a couple of years and ask a typical Toyota master tech whether they'd be recalling several million cars across the world to fix a sticking accelerator pedal, you'd be laughed at in no uncertain terms.

Toyota have been dragged kicking and screaming into that recall, and it's a relatively simple fix. Even then, it's posing them a serious financial problem. It's not difficult to see circumstances in which Subaru might be reluctant to admit any oiling problems, even if they knew about them.

Can't you just pull the green ecu/fuel pump fuse in the engine bay to achieve the same effect? On an really old classic like mine better to pull a fuse than to break a bolt or sensor on removal as these things get old and also the crank sensor on mine has an elongated wire which connects somewhere under the inlet.

+1 :confused: