Found in my oil pump - what the heck is it?
 

As posted earlier, I experienced a catastrophic and sudden loss of oil pressure in my 1990 300E, 103 engine.

Today, whilst performing an autopsy on my oil pump, I found this inside (see pics below).

As you can see, it locked/ruined the pump instantly. The gear and bolt on the front of the pump ripped right off. There was a small tear in the pump screen that allowed the little part to pass into the pump.

By some incredible miracle, the engine is not harmed. I inspected several main and rod bearings and they are fine. They show 250,000 miles of wear, but no trauma. :D :D :D

My guess (and it's only a guess) is that this little culprit is from a valve lifter. It's flat on one side. There's a tiny hole in the middle. The other side is cup-like and polished, like where a pushrod might sit. However, I've never seen a MB valve lifter, so what do I know?

It may have been floating around in the engine for years after being dropped into the engine after a lifter failure/replacement? Or maybe it arrived in the sump recently, although I've heard no lifter noise.

What do you think it is?

BTW, about 250,000 miles and not a bit of sludge in that engine!

Thanks

well
 

i dont know either. but your guess looks plausible. it is a great good fortune that you dont have major bearing damage. i guess until someone identifies it for you i might be tempted to pull the valve cover and take a look.

tom w

Have you every had a valve stem seal job?

The part looks like a ball socket that must be carefully removed with a pencil magnet when a rocker arm is removed. I think they are small enough to go thru one of the oil drain holes in the head.

I don't remember whether or not the ball sockets have a hole in the middle, like yours appears to have. If they do have a hole then it's a ball socket and it may have got there just like I described above.

Edited
I'm almost positive that's a ball socket. And if you know who did the valve stem seal job or other valvetrain work on your car you know who to show that part to.

The next step would be to look at your lifters/rockers/pushrods.

Yeah, it's definitely a ball socket. I can't say how it got loose though. Over the years I've done lots of top end work on 103's and I've NEVER seen one just fall out. This reminds me of something I saw in the early 90's. I had a car in the shop with ZERO oil pressure. When I took it apart I found a "woodruff key/keyway" had beat it's way through the oil pump screen and broken the pump, exactly as in brewtoo's case. The car (I think it was a 140) was only two years old, with about 25K on the clock. It never had any kind of engine work done previously, so the piece must've been in there since the engine was built.

wow
 

you wouldnt expect that from the factory.

but nobody is perfect.

tom w

Years ago I was a Service Manager and we used to find stuff like that right from the factory all the time .. disgruntled, wise guy employees ..

Found a guys lunch inside a seat once and a rattle complaint that tooks weeks to find wound up being a coke bottle in a door panel...

Well, at least my "spare part" looks like a used part, so it probably excuses the factory from the table.

What is a ball socket, where does it go and what does it do?

And I guess my lifter theory is shot. There are no pushrods in an OHC engine. Duh!

Thanks

Goes on top of the valve collets spring seat ...for rocker arm slack adjuster to ride in.

Most like, a mech' lost one and installed another to finish the job...they will just fit down the oil drain back bore or fall though the timing chain chest.

If it was missing from a rocker, you'd hear a noisy lifter.

.

Yes, you are correct in identifying the part.

Looks like I have an extra ball socket if anybody needs one. :rolleyes:

Thanks