Blown head gasket or ...

[hjnorman]

Engine has been producing a very loud chirping/hissing noise on one side that I originally thought was a cracked exhaust manifold. However, after replacing the manifold and gaskets it still made the same noise. :banghead:

Buddy of mine felt around the motor and felt hot hot gases coming from somewhere near where the head and block meet, but we couldn't see exactly where it was at on the motor. I'm hoping its just a blown head gasket but whats the chance it is a cracked engine block? Is this common ... :banghead:

 

[sven]

Yeah thats a common head gasket leak. It should be very obvious once you pull that head off.

 

[MUSKYMAN]

just had the exact same one mine at 160000

 

[bacook]

This perfectly describes my situation... I almost though I had submitted the post in my sleep until I saw the signature! I actually bought a left side manifold assuming it was cracked if anyone's interested.

When you replaced the head gasket, did you also refresh the heads? My 4.2 reads 107-137 on the compression gauge so I know it's tired, but I don't have blow-by coming out of the oil fill which I'm hoping means the rings are still workable. Will a set of rebuilt heads help bring the compression back to the targeted 150-160psi per cylinder?

 

[eliaschristeas]

bacook - when you say refresh, do you mean just polished or fully serviced?

 

[hjnorman]

I haven't gotten to do the repair yet. Unfortunately it'll probably have to wait until summer.

 

[bacook]

serviced. seals, valves and springs checked/replaced, surface planed, etc. I wasn't considering any enhancements.

 

[MUSKYMAN]

I just did cam,timing chain, heads all as one big job.

these things often need a cam just over 100k for a extra $345 for the kit why not do it when your allready in there?

 

[ptschram]

I would expect the slightly lower compression to be more likely due to rings and cam wear, rather than heads. While leaking valve seats will result in lessened compression, if they are leaking that badly, you'd have serious performance issues as well.

When you pull the heads, measure the cam before you put it back together.

 

[bacook]

Good to know.. thanks! I'm disassembling this weekend and will order whatever's necessary next week.