How bad is this engine oil leak?
 

Just bought an '82 300SD Turbo and its got a good bit of oil below the gasket. I've only had it a few days, so I don't know how much of the oil is on the outside of the engine is from years past or if the leak is a bad problem now. Here is what I do know. The oil level is low. The oil registers only on the tip of the dipstick. There are only a few droplets of oil on the floor where the vehicle has been parked for the last 5 days. The oil pressure gauge seems to fluctuate between the 2 and 3 mark while running. I've been reluctant to clean the engine because I figured if I do bring it to a mechanic for a checkout that it might be better to leave it as is for diagnosis. So does this look bad? Is this somewhat typical for this age and make?

http://www.speakeasy.org/~pjohnson/benz/engine2.jpg
http://www.speakeasy.org/~pjohnson/benz/engine2.jpg

It looks like the oil is coming from the valve cover gasket and/or the filler cap. Do you know when the valves were adjusted? If not, I would adjust the valves, which will include replacing the gasket. If the cap is leaking significantly, just replace it. In the mean time, just keep the oil level above the bottom mark.

i'd steam clean it first and watch out where the oil is coming from. a good mechanic will do the same.

Not serious as long as you keep an close eye on the oil level.

Start by cleaning it and replacing the oil cap. See what happens.

...and give it an oil change! It probably needs one...

Clean motor and change filler cap and go from there. (I had a leaky cap on my 560 when I bought it)

Jack Miller
1989 560 SEC

This car was a total gamble purchase. There was no documentation provided and the seller is dead! Yeah, so not sure about if and when the valves were last adjusted. I just assumed replacing the head gasket is really expensive? I know the gasket itself is cheap, but the labor?

I see we have a learning process before us...

Not the head gasket, merely the valve cover gasket. It's a rubber seal that fits around the valve cover...to keep oil from leaking out. A minor fix, although I see some bits attached to the top that would have to be removed.

Still, go get an oil cap and clean things up. Let us know what happens!

I'm curious as to how many miles this SD has.

You are more likely to see a drip mark under a 617 than not - they like to mark their territory.

Can you tell which side of the engine the leak is at? Personally, I would suspect a leak on the passenger side, but your pictures are from the drivers side.
Just in case you are still reluctant to get a new cap, .....yes, get a new cap, then take it from there.

You are confusing the valve cover gasket with the head gasket.

Craig was suggesting a leak on the valve cover gasket, which will take you about two hours to fix when you do it for the first time.

The head gasket will take you 25 hours to fix when you do it for the first time.

You don't have any problems with the head gasket.........as far as we currently know.

Yeah, they are correct.

The valve cover gasket is not that bad to change. The head gasket is much mre serious. This does not appear to be your problem.

Absolutely correct. I know some stuff about motorcycles, but car maintenance is a whole different ballgame. Thank you guys for the info. Good to know i'm dealing with a valve cover gasket, NOT a head gasket. Thanks!!

Odometer is not functional, but according to carfax it had 193K in 1997, so i'm guessing about 250K now. According to the last owner, its been sitting in a garage since 2003.


Tough to say. I can't see the passenger's side very well, but on inital glance it looks to be the corner closest to the driver.

New cap is happening for sure. Thanks everyone for the advice.

I'd work from the top down, the oil filler gasket +valve cover gaskets+crush washers for it are cheap. Personally, I wouldn't do pressure washing an engine, although with a diesel, there's less electrical stuff to go intermittent or bad. Unless you are planning on showing it, I'd just use an old toothbrush,rags, and some engine cleaner. Once I got rid of the source of my leaks (the above), I cleaned the engine that way and the rest of the crud burned off eventually.