Engine help needed...

[jing]

My father's '99 Odyssey developed a coolant leak awhile ago that eventually progressed to the point where it would overheat leaving the car unable to be used. Car was parked for about half a year, and a couple days ago him and a couple of his friends tore the head off thinking it was just a head gasket issue.

I am unsure of some of the terminology as my dad spoke to me regarding this issue entirely in Chinese which I myself am not great at so bear with me.. I did take a bunch of pictures though.

This is what they found..
There is a very visible "scratch" near one of the water channels...


Friend A who is a former dealer mechanic advised my father that the engine is still OK to use but later changed his mind when friend B came along insisting that it was actually NOT OK.

Here are pictures of the head gasket and the head.. you can clearly see where the gasket was no longer sealing allowing the coolant to run loose.




Here is a picture of the entire affected cylinder head just for good measure



It is worth mentioning that my dad told me that when they were taking the head off, one of the heads on one of the 16 head studs broke off while they were trying to remove it. One of the head studs were also not torqued down and took barely any effort to remove. Another of the head studs was damaged like so:




What my dad would like to know is the following:

1. Which of his friends is right? Friend A said that the engine is still OK to use. Friend B says otherwise.

2. Has the head been previously machined before? (Suggesting a past repair)

3. Why would the head studs be damaged? Why would one be loose?

[Impreza]

That loose bolt is it stripped on the block side? I've see many Honda engine where after it overheat the head bolt will come loose and the block side of the thread would be stripped. You can fix this but it is only a temp fix as the aluminum becomes brittle (I think that is what someone told me).
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[Puck Luck]

was this coolant leaking extenaly where you could see it outside the engine or actually burning coolant?
in the first picture, where that scratch is, did you guys use sandpaper or something simular to clean off that area or was it lilke that when you pulled off the head?

[jing]

I was not the one that performed the work so I am unsure of the specifics but will ask my dad to confirm.

I do know that it was burning coolant, and thus the coolant leak was not externally visible.

I believe the scratched area on the head was like that already but will have to confirm.

[Phil@rise]

Excessive heat is what fucked it all up. Heat warps the head and causes the bolts to become rather tight or loose depending on how the head warped. Sometimes the block can warp as well causing the same thing. It was not safe for the engine to be run like that. Have the head machined or at least checked for warpage before reassembling.

[godwin]

1. It depends on your definition of OK and what is the engine, the bottom end is probably fine. Did they do a leak down test on all 6 cylinders before disassembly? Also is the whole engine out? or just the head?

2. You probably can't tell without measuring it on a mill or at least on a deck.

3. The head looks like it has been warped. To be warped, the head has to be distorted / twist enough to bend the bolts out of shape. If your dad is hoping to imply that the engine had been wrecked due to poor previous ownership or mechanical work, I think it will be hard to proof, but chances are the bolts that are loose are the ones that are the furthest bolts from cylinder #2.

Originally Posted by jing

What my dad would like to know is the following:

1. Which of his friends is right? Friend A said that the engine is still OK to use. Friend B says otherwise.

2. Has the head been previously machined before? (Suggesting a past repair)

3. Why would the head studs be damaged? Why would one be loose?