S4 - White smoke from the exhaust

[Obliquegeek]

I've recently picked up a 2003 S4 - 101k, On the way home from work this evening, with the windows open,I noticed the car smelt a bit 'hot'. It wasn't - sat at 90 the whole time. A few minutes later I noticed a bit of white smoke from the exhaust, disappeared quickly. About 5 mins late, again while it slowish moving traffic another puff of white smoke.

I'm new to all this - any thoughts? Suggestions on what to do?

 

[neil ratcliffe]

did it go near the red as the white smoke indicates it may have head gasket on its way out. take the car to a garage they can do a sniff test, which will tell if any combustion gases are getting into the cooling system.

 

[Obliquegeek]

No real 'spirited' driving - was just coming home from work, traffic most of the was along dual carriage way, then stop start through town. Only had it a couple of days... Guess I'll get it to the garage next week then, little disappointing so soon after buying it. Anything I can do to check things in the meantime?

Head gasket - big job?

 

[Mike.M]

Look for mayo in the oil cap, water levels, the oil on the dip stick being oil and not with moisture, fuel or water leaks but these can be difficult unless the leak I see old and has left some kind of staining etc.

 

[Obliquegeek]

Oil cap, dip stick all look fine. Will keep an eye on the coolant.

Had the missus drive the car so I could see the smoke and it's not as white as I first thought. Definitely a blue/grey and smells of engine...

Appears some times when pulling away. Sometimes when choosing to a stop at traffic lights. Doesn't seem very consistent.

 

[Mike.M]

Blue grey means you are burning oil....piston rings possibly, cams possibly

White is more of a coolant leak.

 

[Mike B]

Try letting it idle when hot and rev it hard when stood up outside and able to see better if it gives any smoke from the exhaust.Do you know when it was last serviced and what oil was used?

 

[Obliquegeek]

I think I preferred the sound of it being the head gasket!

It was last serviced about 5000mile ago, not sure on the oil used, will check the receipt.

Couple of questions, apart from the embarrassment of my new car smoking, is it safe to drive carefully for a few days? My wife's car has literally just gone into the garage for some work? Which just leaves the Z4 to transport 3 of us, which obviously ain't going to work!

And, seeing as I've literally just bought it, is there anyway someone could have covered this up to sell it? There was no sign of this while looking at the car, or the next day.

 

[Mike B]

Checking for smoke as I said is a standard part of my car buying.Easy and impossible to hide.If you see any it raises questions and lots is a no no.Depends what yours is doing.We all had Old Smokers years ago when no one worried and you still find them now.Quite safe to drive unless really bad but it might fail MOT

 

[Obliquegeek]

Cheers, I checked for smoke before buying, spent a few hours with the car before parting with any money, hence my last question. I didn't see any sign of it until 2 days later.

It's not lots, but noticeable.

 

[Mike B]

You could try a full oil service .Hard to see why 2days would make any diff

 

[rjm180]

B6 S4's don't really have head gasket problems. We have plenty of other issues, ha ha, but not head gasket failures, under normal use anyway.

 

[Obliquegeek]

Car's going into the garage towards the end of the week to get things checked, I'm useless at these things so I'll leave it to the professionals.

I've noticed the smoke is mainly at low speeds if that makes an difference - pulling away, cruising to a stop and edging forward in traffic. If I rev it hard or put my foot down while driving, it fades away pretty quickly. Ticking along in traffic there is a constant supply of blue haze then if I pull away there's a small cloud.

 

[Mike B]

Not good.The cloud is just what you would see revving after a short idle when hot.It also happens on an over run pulling away after coasting downhill.The engine sucks some oil in and then blows it out when you rev.Usually a sign of wear somewhere but hopefully something else

 

[Obliquegeek]

Oh crap...

 

[monodude]

I wouldnt worry too much, the car is running ok and passed its MOT so emissions cant be that bad..

Check all the obvious things, like is it overfilled with oil, it could be the last owner used 0W30 oil (bit thin for a V8) or similar, I use 5W40 in mine. check/ change the air filter this could be overdue, Check the spark plugs this is a good indication of what is happening with the combustion side (do this after run out). clean the breather system pipes & check the PCV valve (could cause back pressure)
Give the car a good check over/ service and a good run out. The S4's use a fair bit of oil and as they age things wear like the valve guide seal etc.
Main thing is use it, keep an eye on the levels see if they drop or not.
Cheers

Al

 

[Obliquegeek]

Unfortunately I'm pretty concerned already!

Will be doing an oil change, spark plugs, air filter - just haven't found the time yet (and to be honest, the engine scares me!).

No idea what breather system pipes and PCV valve are, but will google it.

Can't really check much else, as I've no idea what I'm doing... Usually rely on the garage.

 

[Obliquegeek]

I've been to a couple of local garages and neither seems too concerned. Just suggested to keep an eye on the level to see how bad it is. I've had it just over 4 weeks now and I've already gone through 3 litres of oil and done about 2000 miles. Seems to drink oil on longer runs, not so bad between work and back (20 mils each way).

The car has de-cats on it, so they've suggested just putting some cats back on to cover the smoking up. They also said it's not worth trying to do anything to sort the engine out internally.

The car has some minor issues that I was aware of, and a few I wasn't - I was intended to slowly get everything done and bring it back to a good condition - but if the engines on it's way out, doesn't' seem much point. Only other option I guess is replacing the engine...

Is there a definitive way to find out what the problem is?

 

[Mike B]

Obviously not good and still points to wear somewhere.Not so bad if the usage is stable and doesnt worsen.Then you could try to live with it rather than look for the cause which is bound to be a costly fix.Replacing the engine would be the worst option cos its bound to be big money

 

[Obliquegeek]

Yeah - I'm resigned to the fact that it's wear and probably not fixable. Would just like to locate the issue for my piece of mind - I'm assuming probably cylinders/piston rings. Checked PCV/breather system and all looks pretty new and shiny, so I'm guessing the owner before me did the same in the hope that it was that.

I could probably live with it if I put some cats on to hide the embarrassing smoking issue, but it's not ideal. (plus I'll miss the sound of the de-cat pipes!) I'll be keeping a close eye on the oil for a while longer to see what happens.

I really wanted to keep the car - hence mentioning replacing the engine. Found a few that are reasonably low mileage and have got someone that can fit it for me without costing an arm and a leg. But obviously there may well be other work that needs doing to any used engine...

 

[Mike B]

You take a risk with shand engines and it might get you nowhere .Why not get a simple compression test?Thats a good way to see if the bores and rings are good.If they are my guess would be that the valve guides are worn which would explain it.A top end overhaul is manageable..My son has an S3 about the same age and miles and that uses a steady amount of oil which he says is down to the guides but he lives with it.His girlfriend has a Mini Cooper which uses a lot more than the S3 but he says they all do cos they are Peugeot based.We have had several 205s and they all used oil cos they are like that

 

[hooblah]

Never heard of valve guides causing it, but perished stem seals will definitely give you smoke on overrun.

 

[Obliquegeek]

I'm obviously no mechanic, but I thought seals would lead to smoke on start up? Don't get anything much until it's up to temp.

Will try compression test, see what that shows. Anyone know what it should ideally be reading?

 

[Mike B]

The oil will be sucked in more as it gets hotter depending on its spec.The tester will know the right readings which should all be the same and hopefully good