OM603 can cylinder head erosion be repair? - PeachParts Mercedes-Benz Forum

Actros617 · #1 08-05-2019, 01:18 PM

I've removed my cylinder head suspecting coolant consumption thinking might be a head gasket or a cracked head (#18 cylinder head) but this is diffrent, it's erosion of the cylinder head on cylinder #5, and there's a few spots of light erosion/rust where (at factory) plugged up the not used cooling holes on the head, the rest of the cylinder head looks in intact with no cracks surprisingly.

Is it possible to repair this erosions? I've seen some machinist would use remove the all of the erosion problem and use a TIG welder and fill the area then finally machine it down to smooth it out

Heres the erosion on cylinder #5

dieselbenz1 · #2 08-05-2019, 01:29 PM

I've had similar repaired with epoxy at a machine shop since it is not in the combustion area. Hardest part was pulling the prechambers.

bsmuwk · #3 08-05-2019, 02:01 PM

Short answer: yes

My machinist and I do this all the time to 603 heads. We're even welding #14 heads with awesome success.

Actros617 · #4 08-05-2019, 02:28 PM

Quote:

Originally Posted by dieselbenz1

I've had similar repaired with epoxy at a machine shop since it is not in the combustion area. Hardest part was pulling the prechambers.

Yeah the prechambers are going to be challenging to remove, but not harder than removing the cylinder head it self.

Quote:

Originally Posted by bsmuwk

Short answer: yes

My machinist and I do this all the time to 603 heads. We're even welding #14 heads with awesome success.

Wow welding a #14 head that's good to know, do you have a recommendations on who to send for welding repair, there's not a lot of options around where i live most wants an exchange and don't want to fix them.

bsmuwk · #5 08-05-2019, 04:04 PM

Quote:

Originally Posted by Actros617

Yeah the prechambers are going to be challenging to remove, but not harder than removing the cylinder head it self.

Wow welding a #14 head that's good to know, do you have a recommendations on who to send for welding repair, there's not a lot of options around where i live most wants an exchange and don't want to fix them.

No one other than the guy's I use in Chicago. He doesn't deal with heads being shipped in though - it's an in person, cash only shop. Old school guys lol

97 SL320 · #6 08-05-2019, 06:23 PM

It looks like something was bouncing around in the combustion chamber. ( Light areas , left lower from the pre chamber )

In any event I would not be concerned about leaving the dents

BillGrissom · #7 08-06-2019, 01:05 AM

Are you referring to the slight corrosion and pitting around the coolant holes? I don't see evidence of coolant leaking past the head gasket passages. You could clean-up the head yourself by abrading it with sandpaper spray-glued to a thick flat sheet of glass. See "Old Skool" (or such) on youtube. He fixes warped aluminum heads that way. Cast-iron would be much slower but you aren't trying to remove much metal.

Look real close at the gasket. Often some ports are supposed to be blocked off by the gasket. Those openings are where sand was shaken out of the casting. When young and dumb, I didn't know that and drilled a hole to "fix" a gasket on a Dodge slant six engine. It started over-heating after 10 min idling, which informed me that passage was supposed to be blocked.

ah-kay · #8 08-06-2019, 12:17 PM

As long as there is no corrosion where the gasket mates with the head then it should be ok. Clean the head up and check. I have seen worse. The combustion is in the prechamber not where the valves are.

Actros617 · #9 08-06-2019, 12:30 PM

Quote:

Originally Posted by 97 SL320

It looks like something was bouncing around in the combustion chamber. ( Light areas , left lower from the pre chamber )

In any event I would not be concerned about leaving the dents

Quote:

Originally Posted by BillGrissom

Are you referring to the slight corrosion and pitting around the coolant holes? I don't see evidence of coolant leaking past the head gasket passages. You could clean-up the head yourself by abrading it with sandpaper spray-glued to a thick flat sheet of glass. See "Old Skool" (or such) on youtube. He fixes warped aluminum heads that way. Cast-iron would be much slower but you aren't trying to remove much metal.

Look real close at the gasket. Often some ports are supposed to be blocked off by the gasket. Those openings are where sand was shaken out of the casting. When young and dumb, I didn't know that and drilled a hole to "fix" a gasket on a Dodge slant six engine. It started over-heating after 10 min idling, which informed me that passage was supposed to be blocked.

Here's cylinder #5 wall has some coolant splash stains/deposits which i find it strange because its very smooth to the touch. Few spins with a ball hone should clean that up nicely. Also (not pictured) when removing the exhaust manifold, the exhaust port #5 had some water lingering in there in it and was consuming a whole coolant reservoir in 3 weeks.

The rest of the cylinder walls looks fantastic still has the hash mark and no cylinder play. Though I find there's a lot of crud buildup around the coolant ducts on the cylinder block.

97 SL320 · #10 08-06-2019, 05:40 PM

This engine sat for a while with a leaking head gasket, you can see where the piston rings were corroded to the cylinder wall. What is the history of this car?

I'd be pulling the piston from # 5 , the rings are very likely corroded in the piston lands. Get this under a high load and the piston will expand but corrosion built up behind the ring will cause the ring to be pressed very hard against the cylinder wall. This will lead to a catastrophic failure. This would be a similar effect to " Piston ring end gap butting "

At minimum the rings won't be holding tension against the cylinder walls when cold.

Diseasel300 · #11 08-06-2019, 06:06 PM

What kind of coolant was this engine running? Salt water? Sheesh!

Actros617 · #12 08-06-2019, 07:10 PM

Quote:

Originally Posted by 97 SL320

This engine sat for a while with a leaking head gasket, you can see where the piston rings were corroded to the cylinder wall. What is the history of this car?

I'd be pulling the piston from # 5 , the rings are very likely corroded in the piston lands. Get this under a high load and the piston will expand but corrosion built up behind the ring will cause the ring to be pressed very hard against the cylinder wall. This will lead to a catastrophic failure. This would be a similar effect to " Piston ring end gap butting "

At minimum the rings won't be holding tension against the cylinder walls when cold.

Overall Unknown of engine actual mileage or its history, as stated previous owner said engine was replaced as sometime before he bought it, the current mileage shows 357k miles on the chassis so its history is a mystery itself.

The owner bought this vehicle in 2015 drove it for 2 years before losing power, then sat for 2 years till i purchased it. I eventually identified power loss due to turbo wastegate transducer leaking and the turbo itself was the culprit (turbine shaft was binding). I have yet to do a compression test due to lacking adequate adapters for testing.

I wish i could pull this engine out and remove the cylinder for inspection but i don't quite have the equipments or knowledge. Tearing into cylinder heads is at my limitations unfortunately.

Quote:

Originally Posted by Diseasel300

What kind of coolant was this engine running? Salt water? Sheesh!

Unfortunately green stuff with and unknown water (tap or distilled) done by previous owners.

Quote:

Originally Posted by ah-kay

As long as there is no corrosion where the gasket mates with the head then it should be ok. Clean the head up and check. I have seen worse. The combustion is in the prechamber not where the valves are.

The headgasket it self looks really good, no tears/blowouts or corrosions on but there's a few areas that has some crystalline build up on the coolant passages

Cylinder 5 looks gasket looks well, (At 6 o'clock position is just stains on the wall not part of headgasket)

97 SL320 · #13 08-06-2019, 09:11 PM

Quote:

Originally Posted by Actros617

Overall Unknown of engine actual mileage or its history, as stated previous owner said engine was replaced as sometime before he bought it, the current mileage shows 357k miles on the chassis so its history is a mystery itself.

The owner bought this vehicle in 2015 drove it for 2 years before losing power, then sat for 2 years till i purchased it. I eventually identified power loss due to turbo wastegate transducer leaking and the turbo itself was the culprit (turbine shaft was binding). I have yet to do a compression test due to lacking adequate adapters for testing.

I'm thinking: The " used " engine head gasket leak / overheating is why he actually stopped driving it not loss / reduction of power.

Can you find a name on the head gasket? Red RTV beads are usually Fel Pro ( aftermarket ) but it could be another brand.

Quote:

Originally Posted by Actros617

I wish i could pull this engine out and remove the cylinder for inspection but i don't quite have the equipments or knowledge. Tearing into cylinder heads is at my limitations unfortunately.

Going farther into the engine isn't any more complicated that lifting a head. This engine isn't going to last as is.

Quote:

Originally Posted by Actros617

The headgasket it self looks really good, no tears/blowouts or corrosions on but there's a few areas that has some crystalline build up on the coolant passages

The steel fire ring 5 to 9 area of cyl 5 looks to have been passing some combustion pressure to the cooling system. The early stages of a gasket failure are very subtle. I've built / repaired countless engines and have seen lots of failure modes.

Doing a cylinder leak down before head removal is always a must when diagnosing compression issues or coolant loss that isn't external to the engine.

You could do a comparative cylinder leak down with the head off by taking a 1/2" thick aluminum plate, rubber sheet and making a single cylinder blocking plate. Just be sure to manually turn the engine so the test piston is fully down so you don't damage the timing chain as the crankshaft rotated under air pressure.

This plate can also be used to test cylinder heads as well.

Diesel911 · #14 08-07-2019, 12:56 PM

For someone who has read the Mercedes Factory Service Manual. Is there anything in the Mercedes Factory Service Manual that tells you can have a crack in the Cylinder head and as long it is X in size you can reuse it like that.

I know on my Volvo diesel that is the case. And when I rebuilt the block I reused the cracked head that was considered within spec with no issues.

If the Mercedes FSM allows some cracking why would you worry about a few pits. Unless the pits are in the sealing area of the gasket.

t walgamuth · #15 08-07-2019, 02:03 PM

Repair on an aluminum head works. We did it on my old Ferrari bout 20 years ago. My machinist welded up the void and milled the gasket seal area. There was a blob hanging into the Hemi combustion chamber. I trimmed that down with a dremel.