My 116 300SD has a strange oil leak. I have looked and looked for it. It seems to be comeing from the front of the injector pump. It runs down to the oil pan. It is not diesel fuel because it is black. I cannot spot this leak and it is driving me crazy. I am taking it to the dealer next friday for its 15,000 mile valve adjustment and motor mounts. How hard are the motor mounts to change? I have heard putting a block under the oil pan to jack up the engine but this worries me. I could save alot of money if I could do it myself.

Thanks.
Dieselman

Dieselman,

Before you take your car for a valve adjustment at 15,000 miles, check the valve clearances. You may not need any valves adjusted. I checked the clearance on the valves in my 300SD after 25,000 and not one needed adjustment. I believe a valve adjustment after only 15,000 miles is excessive. This may be OK for new engines but not older higher mileage engines.

The hardest part of changing the engine mounts is getting at them which translates to much time and high cost. You will need some allen metric wrenches but you should be able to do this job yourself. Putting a block of wood under the steel lower oil pan to raise the engine is no problem, what do you think the dealer is going to do?

If you are interested in maintaining you vehicle yourself, now is the time to start. People here will help you.

P E H

Dieselman,
My 617 engine had the same leak. It was the gasket between the pump and the block. To change it, if its the same or similar engine, you need to remove the oil filter housing, then the pump. Its a long, but doable job. I think I have more info in my "oil leak location?" thread.
Paul

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Paul
2004 E500 4matic; 72,000mi

Motor mounts are not bad to change. Some DIYers have done it once and said "never again" but the key is patience. You'll need a 6mm allen socket for the mount retaining bolts and a long 8mm allen for the thru bolt which goes through the mount and into the engine arm from the bottom. Probably the toughest part of the whole job is lining the arm up and starting the 8mm allen straight without cross threading it. You may need a helper to pry the engine over slightly with a pry bar while you line up the 8mm thru bolt. Sometimes though you get lucky and the bolt goes in straight without any fuss.

As for lifting the engine, place a block of wood on the saddle of your jack (the wood needs to span the width of the oil pan to evenly distribute force) and just lift a little at a time and only do one mount at a time.

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Regards,
Aaron

Thanks for the replies. I plan on posting some pics of this car I am always talking about soon. The thing has had this annoying shake at idle since I got it. I recently changed the rack damper and diesel purged the engine. These things helped some but not enough to satisfy me. I think the mounts will solve it.
Thanks,
Dieselman

Dieselman,

You sound like you have some experience working on your car. I can't understand why you would take it to a dealer for a valve adjustment. Its a very doable DYI job.

The only caution is the get the lock nut very tight so it doesn't loosen and feed the engine a valve.

P E H

The oil leak sure sounds like the pump-to-block gasket. This will be a very tedious job to fix, for the reasons Paul mentioned in his post. Not fun. Perhaps the OM61x engines used a flat gasket here? The later OM60x series have an O-ring that, AFAIK, rarely fails (leaks).

The motor mount job is quite unpleasant and tedious as well. If you attempt this yourself, the FIRST step is a trip to the coin-op car wash with a can or two of engine degreaser. Soak the entire area, both sides, from top AND bottom, and blast it as clean as possible. Otherwise it's straightforward, just no fun. This is one thing that Mercedes fixed on the newer cars, they now have one-piece hydraulic mounts that are a piece of cake to replace - with no silly engine shocks and multi-piece mounting hardware.

I hope the mounts cure your idle shake. My '84 has a shake that I don't like, and is still there after new mounts, valve adjust, new rack damper, injector pop testing, and 2 cans of Diesel Purge. I gave up at that point!


Regards,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Does this oil leak get worse! I have learned a considerable amount from this forum. I changed the dreaded oil filter housing gasket, I have changed the alternator and bracket. One of the most annoying things I ever had to do to it was a window regulator. All thanks to help from the forum. When you guys see the pics of it you are not going to believe I got it for 2300 dollars. It had 129,000 when I got it and now it is at 213,000. I would drive it from now on if it would last.