Why do Diesel engines get so grungy and messy?
 

I finished putting back my 85 300D Diesel engine back in my car this weekend (My indy had plucked the engine from an old lady's car with 160K that he serviced that had been hit in the rear and front.) But not before spending two days chipping and scraping and spraying degreaser over it to get some twenty years and Thirty pounds of sludge off of it.
It dawned on me that when I changed the engine on an 83 Volvo there wasnt even as much as 20 % of this Cr_p.
The worst area is always the big oil pan where crud esconses itself in the 2 sq inch grids of the lattice work of the casting where it meets the transmission. Another place is the crank pulley, which I actually removed to get to the sludge.
Another place is the interior side of the injection pump and of course the engine face. I wanted my engine to look New, like it came off of the assembly line.
It gleamed like aluminum and black jewelry when I was done. I woke up and had my coffee and actually went out to stare at it in disbelief. I dont know how long it will last.

Please post a picture:) I wanna see.

Carrameow It's nice when they are clean. Just did the 300SD yesterday, steam clean, scrub brushes, sailor language. Of course you might see my thread "can get my lights to turn off" - but the bay is looking good. Little mothers on the valve cover, high speed - like chrome. The person I bought it from delivered the title last night and asked my son if we had put a new motor in it :D Of course the 350 pistons comming back from shop laying in the garage probably fed that fire.

Diesels are OIL engines.

They burn fuel oil.

They circulate mass quantities around inside the engine.

Their exhaust can contain traces of soot, black and unburned oil, blue.

Any, and all of the above can leak, and deposit on any surface under the hood. After a while, the volatiles in the oils evaporate, leaving the black, gooey sludge you have found.

Only way to combat this is to start with a clean engine, keep it clean, and plug every leak, no matter how small.

A small fuel leak might just clean off the goo, and not lead to a fire like a gasser... :D

Best Regards,
Jim

Replace some gaskets while the engine is out or it probably won't last long.

Now that it is clean you can find and seal the oil leaks.

My engine is extremly clean, diesels or any engine get dirty if you don't clean them and seal up the leaks.

:D :D :D :D :D I'll shut-up now.

But remember all that oily grunge is keeping the engine corrosion free and shiny underneath it all! If you get it all off you'll have to keep polishing that aluminum or it'll oxidize :P

Mercedes sells or sold a spray-on preservative to prevent oxidation on your engine after you clean it. There is such a thing as too clean.

A diesel's engine oil has a tendancy to be very thick and dense with soot. That's why you can get the grease off your hands easier after working on a gas car.

While a gas car may leak the same amount of oil, it is likely to just drip right off and onto the ground and not "cake" on the motor.. while a diesel's oil leak will cake right onto the motor and make a real mess.. diesel engine oil is some really nasty stuff.