240 DL Oil Leak

I have a 1990 240 DL wagon which has developed an oil leak. It seems
to be dripping and smoking on the exhast manifold toward the
front-right of the engine. I installed an IPD flame trap kit thinking
that it was just building up pressure and leaking out the cap. Going
up a steep hill on the way to the Oregon coast it got very hot and
started POURING out smoke. I pulled over for fear of fire but once it
finished smoking and cooled off I was back on the road. I took it to
the dealership and they replaced the right side valve cover gasket,
"fixed" my oil cap, and gave my flame trap system the thumbs-up. They
said the engine had so much oil on it that they couldn't be sure where
the leak was coming from. This didn't fix the problem. I don't fault
the dealership but would feel more comfortable diagnosing, if not
fixing, this myself. I have read over other group postings on this
subject but would still appreciate some input.

Thanks for any input!

 

Take your car to a DIY carwash, cover the distributor, then spray the
engine with engine degreaser. Let it soak for five or ten minutes,
then wash it all off.

Then, when you have a clean engine, you'll have no trouble finding the
area it is leaking from; then fix it.

 

check the oil pressure switch behind the oilfilter

 

I've had a similar problem in the past on my '89 240 wagon... the engine was
clean enough to determine the oil was coming from the oil filler cap, so I
replaced the rubber gasket in it and it fixed the problem for a year or so.
When it re-occured, I smeared some silicon sealant on both sides of the
rubber gasket, put the cap back on, and have never had any problem since,
even after removing the cap to add or change oil. Each time, I check the
sealant to be sure pieces aren't breaking off, but so far no problem. Seems
like it just "wants" a slightly thicker rubber gasket than stock....

 

Front oilseal failure seams most likely. If so it could be a symptom of
crankcase pressure. i.e., combustion gas passing piston through the cylinder
or through valveguides into rockerbox. It seems to be a common failure on
240 here (England) after about 200,000 miles. M.....

 

Thanks for all the great replies! I have cleaned the engine, siliconed
the oil cap, checked the pressure gauge, and crossed my fingers. If a
definitive solution manifests itself I will be sure to reiterate my
gratitude.