Weird m20 head damage. Repair or replace?

[pandaboo911]

Hey guys, looking to see if anyone has seen damage like this to an m20 head.





It’s strange localized corrosion. The head was resurfaced and head gasket was replaced 1 year ago. It failed a couple weeks ago and these pieces are missing from the head.

Is it worth welding these up or just get another head?

Cheers

[Zambuzan]

what happened?

[justinpirie]

what happened?

No anti freeze?


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[Joegreen02]

Looks like you might have been running too much water in the coolant causing some boiling and cavitation. Get a machine shop to fix it up. Looks repairable


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[zaq123]

Looks like you might have been running too much water in the coolant causing some boiling and cavitation. Get a machine shop to fix it up. Looks repairable


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look more like a galvanic corrosion to me, pretty bad one too. I wouldn't reuse that head. M20 heads can be found cheap

[Joegreen02]

look more like a galvanic corrosion to me, pretty bad one too. I wouldn't reuse that head. M20 heads can be found cheap

Yeah you might be right there. It's probably repairable though. I wouldn't repair it myself but...


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[digger]

the sealing surface is fixable but the issue is what about the corrosion you cant see......

[Andre3127]

the sealing surface is fixable but the issue is what about the corrosion you cant see......

I'd try and fix it if you know a guy who can do the work for cheap, but it's a gamble because there are other coolant passages that could also be corroded.

[Joegreen02]

I'd try and fix it if you know a guy who can do the work for cheap, but it's a gamble because there are other coolant passages that could also be corroded.

Valid point


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[Northern]

The corrosion should be the most advanced at some crevice (Where it meets the head gasket, heater core fitting, thermostat). Probably isn't quite as bad on the inside

[ADEN]

Looks very repairable machine shop fill these missing gaps

[nrubenstein]

Did you grab a bottle of acid instead of distilled water? :p

[pandaboo911]

Prior to this happening I replaced the headgasket, filled it with anti-freeze and water. Then it started to lose coolant quickly, and pressurize the cooling system, overheating at idle.

I imagine it's corrosion but its so localized, I can't see that happening in one year. The rest of the coolant passages look ok. Why would it corrode on just 3 / 6 cylinders?

Is it possible that hot combustion gas was leaking past the headgasket and the cavitation or pressure was eroding the aluminum away?

[zaq123]

Prior to this happening I replaced the headgasket, filled it with anti-freeze and water. Then it started to lose coolant quickly, and pressurize the cooling system, overheating at idle.

I imagine it's corrosion but its so localized, I can't see that happening in one year. The rest of the coolant passages look ok. Why would it corrode on just 3 / 6 cylinders?

Is it possible that hot combustion gas was leaking past the headgasket and the cavitation or pressure was eroding the aluminum away?

last picture has some signs of some combustion leakage, the others look like HG was still holding. This is most likely to the extremely poor coolant maintenance over the years. Coolant looses its properties faster than some think.

Like I said before, I would not reuse this head. There is a high change that there is more corrosion inside the head and one can't tell if there aren't any paper thin spots.

Save your money and time, invest in another head.

[e30davie]

The corrosion should be the most advanced at some crevice (Where it meets the head gasket, heater core fitting, thermostat). Probably isn't quite as bad on the inside

I will agree with this and put a vote in for repair and re-use. but I would get the opinion of a cylinder head re conditioner before doing anything. Everyone has "their guy" and the guy i use has done some decent repairs for me over the years and has also given me the "mate she's stuffed, bin it" as well.