White smoke from exhaust, burning oil

[ArizonaDAK]

My 1990 560 SEL is burning white smoke out the exhaust once the engine is warmed up. This happens after being idle (at a stop light, for instance). Upon acceleration, a big cloud of white smoke puffs out of the exhaust pipe. One more thing, since this has started, I've used 19 quarts of oil (Mobil 1) in just 4200 miles. The transmission fluid is fine. Something's going on here and it appears expensive to fix! I suppose this is a valve job, but I'd like to know for sure before spending all that money. Is there anything short of a valve job that can be done? (I tried SeaFoam without success.) It's taken four weeks advance booking to get the car into the mechanic so I need an answer before Monday May 6th or else the wallet gets sucked dry.

You may have a leak, where your motor oil is leaking into the engine, probably into the combustion chambers.

White smoke is generally the sign of either a faulty head gasket, cracked cylinder head. White smoke is generally a sign that there is water coming into the combustion chamber.
Oil will produce blue smoke.
You said you added 19qt. of oil in 4,200mi.. This is really bad.
Must be a leak somewhere.
That kind of oil consumption is probaly not a valve problem. Most likely a broken piston ring, or broken piston.
Fist thing I would do is check for leaks, second, take a compression test. With that kind of oil consumption, your spark plugs must be clogged with oil. Check this when taking the compression test. One or a few spark plugs will show you where the problem come from.
Keep us posted on your findings.
JackD

[Jim Anderson]

Switch to dino oil before your wallet goes dry.

Check your coolant level, could be water.

Hows the engine temp?

Could just be the head gasket, just thinking of the cheepest most likely thing.
The very cheepest but unlikely, but possible, is youre sucking oil through the crank vent.

Did happen suddently or gradually.

Do a compression check.

Good luck.

[JimSmith]

Burning that kind of oil volume can generate white smoke. If the white stuff lingers for a while and smells like oil, it is oil. Oil burns blue when it is actually being burned pretty thoroughly. Lots of oil will quench the combustion and leave the engine as white, heated oil smoke/mist. You might want to take care of this quickly as your catalytic converter is not going to be happy with the quantity of oil you have put through it.

A dry and wet (squirt some engine oil in the cylinder before the test is done) compression check will give you a good indication of what kind of event you are dealing with - the dry test will tell you the relative condition of your internal engine parts, while the wet test will identify where the faults lie in the weak cylinders. If the wet results are the same as the dry ones, the problem is likely valves. If it gets better wet, you probably have a ring or cylinder wall problem. The head will be expensive but the cylinder and piston repair will be much more expensive. The compression check will be cheap.

Good luck, Jim

[albert champion]

been here. as i have both a 560SEL & SEC.
it is valves and valve guides, i think.

i don't think that you mentioned the mileage on your horse, but it may not matter. my SEL which was driven daily and hard, didn't start consuming excessive oil and smoking until it had gone beyond 220,000 miles[14 years].

on the other hand, my 560SEC, which was driven by a woman who never drove it hard, never got it hot, needed to have the top end renovated at 60,000 miles[14 years].

the SEC was the most amazing case. no smoking most of the time, but if you put your foot into it while decelerating[red light turning green, for example] it would leave the most astonishing cloud of white smoke.

and by the way, when you pull the head, replace the cams and the roller chain. no reason not to.

unless you are going to stop driving the car.

[ArizonaDAK]

I took my 560 into the shop and, as suspected, it was in need of the dreaded valve job. I'm having the other suggested stuff done as well. The mechanic said that the rest of the engine is clean and in good shape for another 200,000 miles. That's good news. The bad news is the hit to my wallet.

[stevebfl]

Always the valve guide/seals on V8s. Never piston or rings. There is probably no greater mechanical certainty in all of auto repair.