400E smoking from the tailpipe and now lazy
Normally heavier oil cannot mask a severe engine problem, since the "heavier" oil when under hot conditions becomes "light" anyway. Older oil tends to be "lighter" also. The question is whether the blueish smoke was present before the mechanic went in. On the other hand he could not damage the engine that bad now you have extensive (oil)smoke released. Can it be just condensate in the muffler systemevaporating? Which shall be just white and disappears as soon as the air desolves it. And that the car now appears "lazy" I cannot relate to the oil type.
Best would be to monitor the oil comsuption over a perilde of time, because if the release is extensive you will see the oil level dropping quick. Another recommendation is to have the compression of the cylinders tested. This would be shedding light on the conditions the cylinders and piston rings are. If this seems to be okay there are still the valve stem seals which can cause oil "flowing" into the cylinders, fouling the spark plugs and reduce the responsiveness of the engine since the mixture is spoiled by engine oil.
Hope it's nothing serious, since those cars are reliable and not receptive to those problems. Mine (inline 6) have both well over 180,000 miles on, and never let me down.
So if the dealership tells you things that don't seem to ad up, or simply seem too expensive, get another opnion! What I describe above is not uncommon and is why many refer to the dealership as the STEALERship!
The other option are the valve stem seals, but they normally dont fail in an instand rather slowly and gradually. It can cause the blueish smoke. But also this seems far fetched. Generally heavy blue (oil moke) are broken piston rings or just worn piston/cylinder surfaces, but normally not at 111,000 mils.
Have the comprossion test done again, but somewhere else, and try to obtain the original protocol of the first compression test, then you may see a clue if there were differences between the two tests.
1) Too much oil in the car
2) Not enough coolant
The mechanic said its a possibity that the excess oil is causing oil to touch the plugs. Also, he said for the 1993 400E i should be using a 20 50 oil, not a 10 40 oil.
So this weekend, I'll drain the oil and replace the plugs. Can't be bothered to clean the old plugs. Also, add more coolant. I will get the compression test redone.
The oil story is another thing. The recommendation to use 20W50 is not bad, depending where you live. If you live in "Normal" climate it seems ok. As I said in my first post, dont use synthetic oil it is to light for older engines. On the other hand overfilling may not cause that severe oil smoke, unless something else comes with it, like the valve stem seals, which allow oil leaking into the upper part of the engine and burn there. So maybe the overfilling increases the oilpressure which then helps the oil to "break" through the valve stem seals and burn and foul the plugs. Under normal oil levels this may still be doing it, but with only little amounts which dont show visibly. this can also be the reason for the sluggish response of the engine since the extra oil is ruining the gasoline/air mixture.
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I have had the same experience changing to synthetic oil on cars with only 10 or 20K. If the car isn't brand new, don't use it.
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