Oil from my tailpipes - help!
Discussion
Hi guys
I've just started up and the S3 is running very rough - oil coming from the tailpipes!!!
I know my rocker cover gasket is on it's way out, however, not being any sort of mechanical expert (although I am learning) would this be the cause.
If not, please can someone point me in the right direction - don't want to go on a run and damage anything as my dip-stick level appears to have dropped as well.
By the way - have checked under the car in the garage for signs of obvious leaks but nothing on the floor.
Awaiting your advises...
Many thanks
Cheers
Jaye
I've just started up and the S3 is running very rough - oil coming from the tailpipes!!!
I know my rocker cover gasket is on it's way out, however, not being any sort of mechanical expert (although I am learning) would this be the cause.
If not, please can someone point me in the right direction - don't want to go on a run and damage anything as my dip-stick level appears to have dropped as well.
By the way - have checked under the car in the garage for signs of obvious leaks but nothing on the floor.
Awaiting your advises...
Many thanks
Cheers
Jaye
How long has the car been standing since you last used it?
Are you sure it's oil?
Is it smoky (as opposed to steam?)
Cars can build up a fair amount of condensation in the exhaust which is then blown out when you start it - it washes carbon of the inside of the pipes so can come out quite black-looking. If that's all it is then nothing to worry about.
If it's oil or it smells of antifreeze, then it's time to start worrying!
Are you sure it's oil?
Is it smoky (as opposed to steam?)
Cars can build up a fair amount of condensation in the exhaust which is then blown out when you start it - it washes carbon of the inside of the pipes so can come out quite black-looking. If that's all it is then nothing to worry about.
If it's oil or it smells of antifreeze, then it's time to start worrying!
Hi.
When you say oil from the exhaust, do you mean there is actually oil dipping from your exhaust tail pipes, or piles of smoke billowing from the car.
A few questions that may help you find the problem;
1. How much oil is the car using / 1000 miles.
2. Does the problem only occur after a long period of lay up.
3. If there is burning oil (smoke), is it worse on the over run, or worse under load.
4. Are there any obvious signs of oil dripping under the engine.
5. Describe any other symptoms including strange noises and running.
I very much doubt the rocker cover gasket leak will cause your engine to burn more oil, but oil may seep into / over the exhaust. Is the rocker cover leaking because of a blocked breather, this may force oil out of the gasket due to a build up of pressure. Running would also be effected, and I guess you may increase the likely hood of forcing oil past the valve stems in to the exhaust.
I hope that helps,
Z
When you say oil from the exhaust, do you mean there is actually oil dipping from your exhaust tail pipes, or piles of smoke billowing from the car.
A few questions that may help you find the problem;
1. How much oil is the car using / 1000 miles.
2. Does the problem only occur after a long period of lay up.
3. If there is burning oil (smoke), is it worse on the over run, or worse under load.
4. Are there any obvious signs of oil dripping under the engine.
5. Describe any other symptoms including strange noises and running.
I very much doubt the rocker cover gasket leak will cause your engine to burn more oil, but oil may seep into / over the exhaust. Is the rocker cover leaking because of a blocked breather, this may force oil out of the gasket due to a build up of pressure. Running would also be effected, and I guess you may increase the likely hood of forcing oil past the valve stems in to the exhaust.
I hope that helps,
Z
Oil is getting into the combustion chamber(s). It could be getting in from above, in which case possibly (1) a head gasket has gone, so that oil from the feed up to the rockers is now escaping sideways into a cylinder. Alternatively (2) it could be a valve guide letting oil into the inlet tract before the petrol is burnt.
Third option is that the oil is getting in from below the piston. There are various reasons for that, including a broken piston ring, badly worn bores, or a holed piston.
You need to isolate this down.
If you can take the spark plugs out, and keep them in order, you should be able to isolate the one that is soaked in oil. If the cause is (1) above then only one side of the engine will be affected (2 separate head gaskets see?) Maybe only one cylinder will be affected.
Again, if (2) or (3) then probably only one cylinder affected.
You can isolate this down further. Disconnect the coil so that there are no ignition sparks, then put your thumb over the spark plug hole you think is affected and get somebody to turn the engine over slowly. You should be able to feel the cylinder compression. Do the same on a cylinder that looks "healthy" on the spark plug examination. If there is a big difference then it's not (2), it's (1) or (3). If there is no compression then it's probably (3).
How fatal this is depends on your view. I wouldn't be particularly fazed by (1) or (2) - they are repairable in a day, with the engine in the car. If (3) I would change the whole engine - again I did my first one of those 30 years ago so it's not the end of the world - expecially as somebody offered me a spare engine last weekend (must get back to him on that!).
It's very difficult to tell without seeing and hearing the engine - experience tells you when an engine is about to claim its pension. I've tried to give you some pointers but if you're not very mechanically-minded, you would really be better to have somebody look at it and tell you the worst.
Third option is that the oil is getting in from below the piston. There are various reasons for that, including a broken piston ring, badly worn bores, or a holed piston.
You need to isolate this down.
If you can take the spark plugs out, and keep them in order, you should be able to isolate the one that is soaked in oil. If the cause is (1) above then only one side of the engine will be affected (2 separate head gaskets see?) Maybe only one cylinder will be affected.
Again, if (2) or (3) then probably only one cylinder affected.
You can isolate this down further. Disconnect the coil so that there are no ignition sparks, then put your thumb over the spark plug hole you think is affected and get somebody to turn the engine over slowly. You should be able to feel the cylinder compression. Do the same on a cylinder that looks "healthy" on the spark plug examination. If there is a big difference then it's not (2), it's (1) or (3). If there is no compression then it's probably (3).
How fatal this is depends on your view. I wouldn't be particularly fazed by (1) or (2) - they are repairable in a day, with the engine in the car. If (3) I would change the whole engine - again I did my first one of those 30 years ago so it's not the end of the world - expecially as somebody offered me a spare engine last weekend (must get back to him on that!).
It's very difficult to tell without seeing and hearing the engine - experience tells you when an engine is about to claim its pension. I've tried to give you some pointers but if you're not very mechanically-minded, you would really be better to have somebody look at it and tell you the worst.
If it is coming from the combustion chambers I'd expect James Bond style massive clouds of blue smoke once it has warmed up a bit.
Are you getting smoke or just black filth out the exhaust?
If you've done some sprinting you could have dislodged some long standing crud if it has had a relatively gentle life till now
If you take the oil filler cap off with it running are you getting smoke out of there or is there any pressure build up?
I'm thinking possibly a blocker breather or something - anyone else any ideas along this line?
As Andrew (TVRGIT) says its not easy to diagnose.
It might not be all that serious - the V6 is a pretty tough old bird.
How about making a video with your camera & putting it on youtube & posting the link here?
Are you getting smoke or just black filth out the exhaust?
If you've done some sprinting you could have dislodged some long standing crud if it has had a relatively gentle life till now
If you take the oil filler cap off with it running are you getting smoke out of there or is there any pressure build up?
I'm thinking possibly a blocker breather or something - anyone else any ideas along this line?
As Andrew (TVRGIT) says its not easy to diagnose.
It might not be all that serious - the V6 is a pretty tough old bird.
How about making a video with your camera & putting it on youtube & posting the link here?
Guys
Many thanks for your input - looks like some investigative work to be undertaken.
Answers to some questions that are known are:
1) Historically has used no oil - only got 36K on the clock.
2) Only been laid up for a week since last used - long run to Curborough (100 miles), then took part in the sprint, then home. Only started playing up when next started a week later.
3) Have to check on that one
4) Definately not - only oil is actually coming out of the tailpipe (spray mist of oil)
5) Struggles on idle & sounds very rough on over run - fine under load.
Hope this helps.
Look forward to receiving any further thoughts - won't be able to get to work on anything until weekend after next now - will keep a note of all comments and let you know how I get on.
Don't suppose anyone's in the Wakefield area on weekend of 9th August are they - might need a bit of help????
Cheers
Jaye
Thanks again
Many thanks for your input - looks like some investigative work to be undertaken.
Answers to some questions that are known are:
1) Historically has used no oil - only got 36K on the clock.
2) Only been laid up for a week since last used - long run to Curborough (100 miles), then took part in the sprint, then home. Only started playing up when next started a week later.
3) Have to check on that one
4) Definately not - only oil is actually coming out of the tailpipe (spray mist of oil)
5) Struggles on idle & sounds very rough on over run - fine under load.
Hope this helps.
Look forward to receiving any further thoughts - won't be able to get to work on anything until weekend after next now - will keep a note of all comments and let you know how I get on.
Don't suppose anyone's in the Wakefield area on weekend of 9th August are they - might need a bit of help????
Cheers
Jaye
Thanks again
Jaye R said:
4) Definately not - only oil is actually coming out of the tailpipe (spray mist of oil)
It's exceptionally unlikely that you actually have oil spray coming out of the exhaust. The only significant source of oil is the engine, and the only route out of the engine is via the combustion chamber, and any oil coming out of there will be burned and come out as blue smoke rather than liquid oil.It's been suggested earlier that what you're seeing is water and soot. You seem to have decided it is oil and not water, but I suggest you have another think about it because water is hugely more likely.
I suggest you hold a white kitchen towel in front of the tail pipes and let it collect some of the fluid, then leave it to dry. If it dries and leaves a black/grey/brown stain on the paper, it was water. If it stays wet and gooey maybe you really do have oil coming out. The only way I can see you getting liquid oil out is via a blown exhaust valve stem seal allowing oil straight into the manifold. This would burn in the exhaust if it was hot, but on a dead cold engine could get carried downstream far enough to escape the heat. This is pretty unlikely though and I think it's far more unlikely that all you're seeing is perfectly normal condensation mixed with soot.
All, if it was a misfire would it throw enough fuel through when it misfired to give these symptoms?
I'm not sure it would, but then I guess an injector could be stuck open but not sure how likely this is.
Well worth taking the spark plugs out if it is down to a single cylinder I reckon this will tell you which one.
Do the kitchen towel test and see if you can set fire to it - preferably away from the car!
If all else fails take it out and give it a damn good thrashing (John Cleese style if you like!)
It won't fix it but you'll feel better
I'm not sure it would, but then I guess an injector could be stuck open but not sure how likely this is.
Well worth taking the spark plugs out if it is down to a single cylinder I reckon this will tell you which one.
Do the kitchen towel test and see if you can set fire to it - preferably away from the car!
If all else fails take it out and give it a damn good thrashing (John Cleese style if you like!)
It won't fix it but you'll feel better
Edited by Barkychoc on Friday 25th July 16:31
Barkychoc said:
All, if it was a misfire would it throw enough fuel through when it misfired to give these symptoms?
If it's throwing unburnt fuel out the back you'll smell it and be in no doubt what it is. It's almost certainly water imo. If you were throwing any oil out the back you'd also be producing a thick blue smokescreen because at least some of it would certainly burn, but you can rule out the remote possibility that it really is oil with the paper towel.GreenV8S said:
Barkychoc said:
All, if it was a misfire would it throw enough fuel through when it misfired to give these symptoms?
If it's throwing unburnt fuel out the back you'll smell it and be in no doubt what it is. It's almost certainly water imo. If you were throwing any oil out the back you'd also be producing a thick blue smokescreen because at least some of it would certainly burn, but you can rule out the remote possibility that it really is oil with the paper towel.If it's water, of course, the next question is "does it smell of antifreeze"?
No wait tvrgit, calm down, calm down... step at a time boy!
tvrgit said:
GreenV8S said:
Barkychoc said:
All, if it was a misfire would it throw enough fuel through when it misfired to give these symptoms?
If it's throwing unburnt fuel out the back you'll smell it and be in no doubt what it is. It's almost certainly water imo. If you were throwing any oil out the back you'd also be producing a thick blue smokescreen because at least some of it would certainly burn, but you can rule out the remote possibility that it really is oil with the paper towel.If it's water, of course, the next question is "does it smell of antifreeze"?
No wait tvrgit, calm down, calm down... step at a time boy!
Go with Peter's paper towel test as your next step, and then the plugs one by one and taking care not to mix up the order.
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