Hope I am posting in the right area as I am new to the forum.
My wifes Z3 2.2 2001 with 86000 miles on the clock which we have had for over 6 years has started to use a lot more oil than usual and I noticed when I topped it up that there was the old yellow gunge on the oil filler cap. Wife does 2, 15 mile journeys a day at present so it could be lack of warm up in the cold weather we have had recently.
The engine is not losing water so dont think its cylinder head gasket but after topping up oil there is a lot of oil smoke on start up, which leads me to think its valve stem oil seals.
question is can they be changed in situ with the head on and the camshaft off or do I have to take off the head, looking at the techy stuff it mentions air compressors and all sorts. I do all jobs but dont want to tackle something that is going to leave me up S*** creek.
Anybody got any ideas.
valve stem oil seal replacement
-
Guest
Seals
The valve stem seals should last for ages - I would not suspect anything really amiss with the engine.
What type and grade of oil are you using? A very thin oil such as 0-30 (particualrly if not fully stnthetic) will tend to burn off if the engine is run cold for most of its use - as is witnessed by the 'mayonnaise' inside the filler cap.
I would change to a 10-40 and see if there is any difference.
What type and grade of oil are you using? A very thin oil such as 0-30 (particualrly if not fully stnthetic) will tend to burn off if the engine is run cold for most of its use - as is witnessed by the 'mayonnaise' inside the filler cap.
I would change to a 10-40 and see if there is any difference.
Don't strip the head off yet, either buy a compression tester (approx £25) or get a garage to do it for you.
Do the test then repeat again with a teaspoon of oil in each cylinder (down sprak plug hole). Record results both times and come back here with your findings so we can advise further.
Do the test then repeat again with a teaspoon of oil in each cylinder (down sprak plug hole). Record results both times and come back here with your findings so we can advise further.
Sapphire Black 02 S54 M Roadster
Yea I wouldn't touch the valve stem seals as they shouldn't be "worn out" at that mileage. However, what does kill them is lack of oil changes which makes them brittle so it could be that if it's had loads of short journies (otherwise they should last the lifetime of the engine).
Might be worth as suggested above, putting a thicker oil in it.
Might be worth as suggested above, putting a thicker oil in it.
-
Guest
Breather
Check your crankcase breather pipe too - it comes out just behind the inlet VANOS solenoid, and should go into the front bottom of the inlet manifold via a solenoid valve.
If the hose is leaking, air will be drawn into the crankcase, which will then be pressurised, and pass oily vapour past the piston rings and valve seals.
I woud still suspect the oil, though - what grade is it, and when was it last changed?
If the hose is leaking, air will be drawn into the crankcase, which will then be pressurised, and pass oily vapour past the piston rings and valve seals.
I woud still suspect the oil, though - what grade is it, and when was it last changed?
This just about sums it up (lift from web)...
Generally, engines burn oil due to a few reasons.
Bad valve seals
Worn valve guides
Pressurized crankcase (oil pan) due to a clogged PCV valve or breather system
Blow-by from worn piston rings
Bad valve seals: The valves are located in the cylinder head above the combustion chamber. Oil is pumped at 50 to 80 psi of pressure into the top of the head, lubricating the valve-train; the valves have seals on them to stop the flow of oil down into the engine when the valve is open. If the seals fail, oil is allowed to flow down into the combustion chamber and is burned.
Worn valve guides: The valves are guided by a small cylindrical chamber called a valve guide. These guides wear over time causing eccentricity (or slop); the excess gap allows the flow of oil down the valve stem into the combustion chamber to be burned.
Pressurized crankcase due to clogged PCV or breather system:The car's engine is a giant pump, consequently it must breathe. The PCV (Positive Crankcase Ventilation) system does just this, allows the engine to exhaust the excess pressure build-up (which is a natural phenomenon of the internal combustion engine). Carbon build-up is a by-product of an engine and can build up in the PCV system, clogging the breathing passages. This in turn pressurizes the oil pan and pushes oil up into the fuel delivery system, where it is fed into the engine and burned.
Blow-by from worn piston rings: The pistons in your car's engine have seals around them in the form of rings. These rings do two things:
1. Seal the combustion chamber so the precious power developed from the firing of the cylinder is not lost.
2. Provide vital lubrication to the cylinder walls.
When the rings wear out, the pressure from combustion reverses down into the oil pan, pressurizing it and forcing oil into the valve covers, through the breather system, back into the fuel delivery system, and into the engine to be burned.
Generally, engines burn oil due to a few reasons.
Bad valve seals
Worn valve guides
Pressurized crankcase (oil pan) due to a clogged PCV valve or breather system
Blow-by from worn piston rings
Bad valve seals: The valves are located in the cylinder head above the combustion chamber. Oil is pumped at 50 to 80 psi of pressure into the top of the head, lubricating the valve-train; the valves have seals on them to stop the flow of oil down into the engine when the valve is open. If the seals fail, oil is allowed to flow down into the combustion chamber and is burned.
Worn valve guides: The valves are guided by a small cylindrical chamber called a valve guide. These guides wear over time causing eccentricity (or slop); the excess gap allows the flow of oil down the valve stem into the combustion chamber to be burned.
Pressurized crankcase due to clogged PCV or breather system:The car's engine is a giant pump, consequently it must breathe. The PCV (Positive Crankcase Ventilation) system does just this, allows the engine to exhaust the excess pressure build-up (which is a natural phenomenon of the internal combustion engine). Carbon build-up is a by-product of an engine and can build up in the PCV system, clogging the breathing passages. This in turn pressurizes the oil pan and pushes oil up into the fuel delivery system, where it is fed into the engine and burned.
Blow-by from worn piston rings: The pistons in your car's engine have seals around them in the form of rings. These rings do two things:
1. Seal the combustion chamber so the precious power developed from the firing of the cylinder is not lost.
2. Provide vital lubrication to the cylinder walls.
When the rings wear out, the pressure from combustion reverses down into the oil pan, pressurizing it and forcing oil into the valve covers, through the breather system, back into the fuel delivery system, and into the engine to be burned.
Sapphire Black 02 S54 M Roadster
Of course, the other possibility is that it is not being burned at all but is simply leaking somewhere. You'd generally always notice this on your driveway though.
I don't think a simple change of oil grade will help a great deal with the amount of oil you are going through.
I don't think a simple change of oil grade will help a great deal with the amount of oil you are going through.
Sapphire Black 02 S54 M Roadster
Thanks for all the ideas, I'd never thought about breather pipes being clogged so will check that out at the weekend.
I use 5W-30 fully synthetic and did wonder about using a 10w-40 in case it was too thin now that there is a reasonable mileage. ( I had to change to 10w-40 in my Porsche). Oil changes have been done like all the servicing by myself, as and when the service lights get down to 2 greens.
I will have the cylinders compression tested to see if they are all the same.
Definitely havent got an oil leak, that only happened after the first service we had done by a dealer when we got the car in 2002.
I use 5W-30 fully synthetic and did wonder about using a 10w-40 in case it was too thin now that there is a reasonable mileage. ( I had to change to 10w-40 in my Porsche). Oil changes have been done like all the servicing by myself, as and when the service lights get down to 2 greens.
I will have the cylinders compression tested to see if they are all the same.
Definitely havent got an oil leak, that only happened after the first service we had done by a dealer when we got the car in 2002.
..very easy test for you - remove the dipstick and start the engine. Cover the dipstick hole with your thumb and see if there is any positive pressure there. If there is lots, you have a blocked breather.Thanks for all the ideas, I'd never thought about breather pipes being clogged so will check that out at the weekend.
Sapphire Black 02 S54 M Roadster
You mention 'yellow gunge' on the oil filler cap. Are you sure the engine is getting up to temperature and that you don't have a faulty thermostat?
Unless the temperature gauge quickly goes to the centre position or just above then I would strongly suspect the thermostat. Cold running can play havoc with performance and oil degrades very quickly.
I now realise that when I was looking for my Z3 nearly all the 6 cylinder cars I looked at had thermostat problems.
fairly easy DIY job though but part quite expensive for a thermostat.
Unless the temperature gauge quickly goes to the centre position or just above then I would strongly suspect the thermostat. Cold running can play havoc with performance and oil degrades very quickly.
I now realise that when I was looking for my Z3 nearly all the 6 cylinder cars I looked at had thermostat problems.
fairly easy DIY job though but part quite expensive for a thermostat.
