Shop said my heads are not cracked, just warped. I am weary of the diagnosis though

[4flyer]

This is a follow-up to this thread:

https://www.toyota-4runner.org/3rd-...f-these-compression-readings.html#post3853378

Hi guys,

For this slow running project, I finally got word from the machine shop what they found.

They said, to my surprise, they did not find a crack in the heads but the passenger side head (where I had low compression and coolant in the cyl #3) was warped. They were able to resurface the head and they also said two valves needed work. I did not have them look at the head gaskets but I did not find any issues and it is a metal gasket so cracks are not common.

So a warped head was able to dump enough coolant in the cylinder to let it pool in the cylinder?

I am just worried that the head is not okay. The idea of a warped block seems unlikely. I did not overheat the engine. Any overheating here would have been local.

I am having the machine shop do a submerged pressure test now. What else should I look for? I don't want to put all this money and effort into this to only miss the issue.

Thanks!

 

[3bears]

I was told that there is also a 2 part chemical system for looking for cracks. Im not sure how they really do it. I had a head that had a crack in an exhaust valve area not in the combustion chamber, I dont know how they found it and I did not ask.

 

[Pyral]

A warped head can cause it to leak oil/coolant/pressure, it's why there are specifications in the service manual for it.

But I don't understand why the heads would warp for no reason. It's possible at some point in the engines life it was over heated and it had been just barely holding on, maybe it barely met specification new. I've heard of head gaskets on 100 series failing from age.

Machine shops have several tests to find cracks. They can put a magnet on the engine and sift magnetic dust over it, and the dust will stick unevenly around the cracks.

I think they have very fine powder that falls into the cracks and remains after you blow it off. Then there is the pressurized submerging method.

I'd check the block for warpage just in case.