Head problems

[D22_dogg]

Ok so like 90% of all zd30 nav's, i cracked my head 6 months ago!
Changed with a brand new one, and did the turbo, water pump, drive belt and tensioner and radiator aswell.
Here we are 6 months on and the radiator is boiling and filling the expansion tank and just blew the ass out of the radiator again exact same symptoms as before so obviously cracked another head my $10g nav now owes me $20g and im getting a little upset
Any ideas why i could be cracking heads ....


Never thought ide say this but "I HATE HEAD" s

 

[jonney]

sounds unusual . what causes the cylinder head to crack is mainly due to cold water contacting the hot surface of the cylinder face, just like adding boiling water to an ice cold drinking glass or filling up the radiator when the engine has run hot without having the engine running to circulate the water properly.
maybe in your case the fault could be a blown head gasket but the only way to find out is to remove the cylinder head and have a close look at the gasket then go from there. did you replace the Thermostat when all the other parts were replaced ?

 

[D22_dogg]

Yeah i replaced the thermostat also and obviously the head gasket aswell i guess ill pull the head off and have a closer inspection but bloody hell what a pain in the ass of a job...

 

[jonney]

yes i do feel for you having to go though this again , you might have to get the cylinder head machined so its dead true at the mating surface to block but hopefully its just a tiny leak at the gasket which is causing this overheating and if no damage is done the head surface could be ok and no need to machine. the other thing is if your going this far in removing the head again you want it to be the last time you do it so maybe it could be worth your time to have the head xrayed and machined before you put it back together with a new gasket .

 

[ben85]

As you know its not uncommon for them to crack heads.
I dont really know why but they do.

I had a new head fitted at 180, 000ks after it was pumping coolant out of the overflow, 5 years and 45, 000ks later and its starting to pump coolant out sometimes on long trips.

Its pressure tested fine, so who knows, maybe it only leaks when its working hard etc.

If it gets worse ill worry about it then, but options for me would be to sell it as is cheap, fix and sell soon after or swap in a used/reco engine, i suspect if its the head again it will be likely to go again down the track so too risky to put another head on it and keep long term.

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