OM603 Valve Guide Seals - Page 3 - PeachParts Mercedes-Benz Forum

phlfly · #31 01-16-2018, 09:33 PM

what is involve to remove turbo on this cars?
Also place to rebuild turbo? any suggestions?

JHZR2 · #32 06-21-2024, 06:12 PM

Bringing this one back from the dead with the hopes of reviving one of my 350 SD cars. It’s the low mileage one which had a slowly seeping (oil into coolant) head gasket, but ran beautifully and very strong. I proactively had the head gasket done, and afterwards I now have low compression, and what my mechanic calls a misfire.

My mechanic is rather old, and just informed me that he is shutting down his shop, and will be unable to remediate the engine which he has had for a number of years now. So it’s on me to diagnose and figure out how to fix, if I can.

He had a job done, and the information he provided shows that they replaced the valve seals. It would be my suspicion that if there are two different diameters, and the small one was installed on the wrong valve, it might get stuck and not seal properly.

Is this plausible? When you had incorrect seals on the valves did you have a rough running engine? It will take me a few days to get to the car and get it running again. I don’t know what I’ll find, I don’t know how much time I’ll have to diagnose it right away. I’m hoping that it is something stupid like this, because it does seem like my mechanic was pretty rigorous otherwise in terms of trying to investigate. Granted, I don’t have the compression numbers available.

Diseasel300 · #33 06-23-2024, 10:41 AM

Leaky valve guide seals have no impact on mixture or running characteristics in a diesel engine. They can lead to excessive crankcase blowby when under boost and dribble oil down the stems when idling/parked both leading to excessive oil consumption or smoke, but not poor running.

Low compression after head work that was not present before would lead me to suspect either a botched head gasket job or valves not sealing. If you didn't replace the valve guides and have the valves lapped when the head was off, you did yourself a massive disservice. The original iron guides wear and let the valves flop around leading to tuliping and poor sealing with mileage. The replacement phosphor bronze guides that are available should last the life of the engine.

JHZR2 · #34 06-23-2024, 10:57 AM

Quote:

Originally Posted by Diseasel300

Leaky valve guide seals have no impact on mixture or running characteristics in a diesel engine. They can lead to excessive crankcase blowby when under boost and dribble oil down the stems when idling/parked both leading to excessive oil consumption or smoke, but not poor running.

Low compression after head work that was not present before would lead me to suspect either a botched head gasket job or valves not sealing. If you didn't replace the valve guides and have the valves lapped when the head was off, you did yourself a massive disservice. The original iron guides wear and let the valves flop around leading to tuliping and poor sealing with mileage. The replacement phosphor bronze guides that are available should last the life of the engine.

TBH I don’t know what the machine shop or mechanic did.

This disaster has been like five or more years in the making. I don’t even remember when I dropped my car off.

Now the mechanic is retiring and can’t fix it. So I’m trying to rectify the situation. The mechanic knows these cars well. I can ask him when I see/talk to him again. I’m pretty sure that was all done though.

What queued me into this thread was the possibility that the valve seals, which seem to have two different sizes and diameters, could possibly cause a valve to hang up.

It seems that human error for such a thing would be far more likely than other things, if this can happen.

Right now I have two cars that I’m chasing issues on. And zero time. Very frustrating.

Diseasel300 · #35 06-23-2024, 11:26 AM

Quote:

Originally Posted by JHZR2

What queued me into this thread was the possibility that the valve seals, which seem to have two different sizes and diameters, could possibly cause a valve to hang up.

It seems that human error for such a thing would be far more likely than other things, if this can happen.

The size differences aren't very large and the lips are held in place by a spring ring. With the oil splashed on them, the chances of a valve guide seal causing a valve to bind are zero. The return springs are EXTREMELY strong and would overpower any binding caused by a tight seal. If nothing else, if the seal seized on the shaft for some reason (which I don't see how that would even be possible), the valve spring would yank the seal right up off the guide or tear the rubber out from the return force. If the seals went on without hammering them in place with some sort of driver, you can be rest assured they're not causing a valve to hang up.

JHZR2 · #36 06-23-2024, 11:48 AM

Quote:

Originally Posted by Diseasel300

The size differences aren't very large and the lips are held in place by a spring ring. With the oil splashed on them, the chances of a valve guide seal causing a valve to bind are zero. The return springs are EXTREMELY strong and would overpower any binding caused by a tight seal. If nothing else, if the seal seized on the shaft for some reason (which I don't see how that would even be possible), the valve spring would yank the seal right up off the guide or tear the rubber out from the return force. If the seals went on without hammering them in place with some sort of driver, you can be rest assured they're not causing a valve to hang up.

Thank you.

My plan is to compression test and then do a leak down to try to listen for what is leaking.

I’ll make another thread when I start to get data. I’d sure appreciate your thoughts on that when I make it.

Thanks!