OM602 Head Gasket Failure? Investigation - Page 4 - PeachParts Mercedes-Benz Forum

jay_bob · #46 06-27-2014, 09:20 AM

#2 cylinder looks suspect, I see damage on the edge of the piston and bare metal instead of the soot.

What's up with the scratch mark on #1 cylinder piston?

A couple of the other pistons I can see pock marks - cavitation?

On the head, the cylinders 1-4 all show normal soot deposits, except on a couple it has gotten pulled off, probably when the seal was broken between the head and head gasket.

However, on cylinder #5 the head looks oily and I see droplets in the oil film.

ichris93 · #47 06-27-2014, 10:30 AM

Quote:

Originally Posted by jay_bob

#2 cylinder looks suspect, I see damage on the edge of the piston and bare metal instead of the soot.

I will have to give it a closer look. I think there is minimum damage on the edge but I did not see any bare metal.

Quote:

What's up with the scratch mark on #1 cylinder piston?

If you look at the picture with the whole block the scratch is not there so I do not think there is actually a scratch on the piston.

Quote:

A couple of the other pistons I can see pock marks - cavitation?

Pock marks? Where?

Quote:

On the head, the cylinders 1-4 all show normal soot deposits, except on a couple it has gotten pulled off, probably when the seal was broken between the head and head gasket.

However, on cylinder #5 the head looks oily and I see droplets in the oil film.

If you look at the picture of the whole head it is not like that. That was from sitting over night before I got close up pictures.

Are you guys trying to get me to pull the block now and do a bigger rebuild?

I hope it is not necessary.

vstech · #48 07-15-2014, 05:35 PM

I would clean the #2 cylinder totally, then spray in some crack finder and look over the entire cylinder... Possibly need to pull the piston...

ichris93 · #49 07-31-2014, 07:57 AM

Quote:

Originally Posted by vstech

I would clean the #2 cylinder totally, then spray in some crack finder and look over the entire cylinder... Possibly need to pull the piston...

What is the best way to clean the cylinder?

Sorry for the late response. I just got back in town from a vacation.

ichris93 · #50 07-31-2014, 08:26 AM

I did a little cleaning and think I got a pretty good picture...

or pretty bad...

vstech · #51 07-31-2014, 06:45 PM

Wow, that looks bad. It looks like a previous head gasket or intake open left water in that cylinder for a year, and it rusted badly... You might have a bent rod also...

vstech · #52 07-31-2014, 06:48 PM

What kind of money can you come up with? I think I can get you an engine.

ichris93 · #53 07-31-2014, 09:15 PM

Quote:

Originally Posted by vstech

Wow, that looks bad. It looks like a previous head gasket or intake open left water in that cylinder for a year, and it rusted badly... You might have a bent rod also...

Rust would leave a weird design like that? Not sure about the rod or how to check that short of removing it.

Quote:

Originally Posted by vstech

What kind of money can you come up with? I think I can get you an engine.

I do not know if I would spend the money on an engine for it. I think this has been more than I've bargained for. Would that cause a problem anymore? I just felt the sleeve and it seems like the rings have honed it to the same size.

vstech · #54 07-31-2014, 09:21 PM

If the sleeve is letting water in, it's gotta come out, replaced and be honed to size, and likely the piston needs replacement. If the rod is bent, it'll need to go as well...

ichris93 · #55 07-31-2014, 09:23 PM

Quote:

Originally Posted by vstech

If the sleeve is letting water in, it's gotta come out, replaced and be honed to size, and likely the piston needs replacement. If the rod is bent, it'll need to go as well...

Why do you think the sleeve is letting water in?

vstech · #56 07-31-2014, 09:44 PM

all the water cavitation damage to the piston, and the original cooling system problems you were having that caused you to pull the head off.

ichris93 · #57 07-31-2014, 09:52 PM

Quote:

Originally Posted by vstech

all the water cavitation damage to the piston, and the original cooling system problems you were having that caused you to pull the head off.

I think the cylinder looks like it has cavitation damage, smoothed down now, but I thought the edge of the piston was just chipping and not cavitation damage. You would know better than I would though.

How does a sleeve allow water in?

ichris93 · #58 08-03-2014, 12:31 PM

So what should I do?

Car over heated. Bubbling in coolant. Compression okay. Pulled head. Piston two looks like the edges are chipped. Cylinder 2 sleeve has weird markings.

Mxfrank · #59 08-03-2014, 02:31 PM

You're going to have to make a choice. The bottom end will need work...at the very least, one new piston and sleeve. The head needs to be cleaned up by a machine shop, where they may find additional problems. If you have the cash and the will, do it. Next best choice would be a used replacement motor. And finally, you can scrap the car.

This damage was probably due to some sort of abuse: allowing water into the intake, flooding, some idiot playing with water injection, badly contaminated fuel, or running pure water or a weak glycol solution for an extended period. Once a pinhole in the liner allows coolant into the chamber, cavitation damage multiplies. It's not going to get better without help. The nature of this problem suggests that there may be similar damage forming in other liners...the only way to tell would be to pull them all. It's bad news.

ichris93 · #60 08-03-2014, 02:45 PM

Quote:

Originally Posted by Mxfrank

You're going to have to make a choice. The bottom end will need work...at the very least, one new piston and sleeve. The head needs to be cleaned up by a machine shop, where they may find additional problems. If you have the cash and the will, do it. Next best choice would be a used replacement motor. And finally, you can scrap the car.

This damage was probably due to some sort of abuse: allowing water into the intake, flooding, some idiot playing with water injection, badly contaminated fuel, or running pure water or a weak glycol solution for an extended period. Once a pinhole in the liner allows coolant into the chamber, cavitation damage multiplies. It's not going to get better without help. The nature of this problem suggests that there may be similar damage forming in other liners...the only way to tell would be to pull them all. It's bad news.

I am trying to decide which choice to make.

What is the main concern here? The damage to the piston or the design on the sleeve? The sleeve feels smooth. There are no groves that I can feel with my fingers so I am not sure how it could let coolant in.

The head I was expecting to do work on. Valve seals replaced, relapped and seated. Also have the pre chambers resealed. The bottom end is where I do not really want to mess with. My neighbor, a BMW mechanic, says if the head checks out to put it back together. He thinks the picture makes it look worse than it actually is.