1992 500e Engine noise, Engine out
 

I started another thread on 500ecstasy.com

Local dealer spent 15+ hours trying to figure out engine noise, no luck. They did it all, boroscope, video scope, carbon clean, compression test, etc.

Compression is 10lbs lower than the others on cyl #2 but still in spec.

They took valve covers off, nothing. They took the engine out, turned it upside down,pulled the pan, nothing. Clean. Well cared for 187k miles.

So, as you see in the photo engine and trans are in the back of my 77 dodge power wagon going to another mechanic to have the head pulled.

The shop foreman says he thinks its a scuffed piston skirt.

Any other guesses?

The could not pull the piston out from the bottom because of the counter balance.

There is video of the noise on youtube.

http://www.youtube.com/watch?v=FIkzrqDTF2c

Oiler tubes on the heads when they crack limit flow to the cam and lifter and can make that noise. Pretty common on 400E and 500E's might look at that.

Macdrone,that is the proverbial nail you hit on it's head :P , It's just hardend oiler tubes and could have been fixed in a few hours by a mercedes mechanic .Ye gods, I wonder some times ...:D

If the MB stealership spent 15 hours and still can't figure the problem out....come on!

Any competent mechanic who has experience on MB's will know what the problem is. And it won't take 15 hours!

Most of the staff at our local stealership service departments are computer jockeys (not mechanics - technicians).Heaven forbid they get their hands oily. If the diagnosis computer won't tell ' em where a mechanical problem lies, then they are lost. :rolleyes: You need to go to an Indie with old school MB trained hands on mechanics.

Oil starvation, need engine lubrication.

Drain the oil, put fresh oil in and use one quart of Lucas Heavy Duty Oil Stabilizer or Marvel Mystery Oil as a replacement for one quart of oil.

Actually, the tubes are made in two pieces, the main body and a little cap glued in the end to close it off. The cap tends to blow off on all the ones I've seen. These tubes could have been made differently - I suspect they were intentional in their design. We still have a lot of people around with S420's and E420 that are still rolling the M119 engine (though I still like the M113 better - near bullet-proof).

The dealer says they checked the tubes as one of the first things. This dealership has treated me very well, and they have very experienced mechanics. But, we'll see if they made a mistake. I did change the oil, first thing, made no difference.

Someone mentioned 'cracked oil tube" is that different than one blowing off the plug.

If so, then I can see they'd have to pull them to determine the problem.



Michael

M119's should be cheap in the salvage yards - I'd look around for another engine before I would put much time and effort into an engine that could have piston/bore damage. Real Mercedes parts to rebuild these engines properly are not cheap, nor the labor to do it competently.

Cracked oiler tubes same difference as if they popped out. I wouldnt say there was any bore damage just lack of knowledge on the mechanics. Most rebuild parts are cheap but Im pretty sure just pulling valve covers and replacing those tubes would fix that. Its not knocking.

I have a used engine on standby. I saw the engine with oil pan off, upside down, no damage to the block. They did see a couple "shiny" spots on the top of the piston with the scope at 10 and 4 o'clock.

Well good gas will keep the top of the piston clean in those spots. Its where the valves open up at.

If you can see there was no visual bore defects.. I don't see how a piston skirt could be scuffed. mating wear surfaces have the same marks...

But used motors are plentiful- but then you'll still need to do tubes and timing chain/guides.

Michael

What does this mean - the dealer checked the oil tubes? All this talk of cracked tubes and displaced plugs would apply to plastic tubes but you have metal.