Engine trouble

[proxses]

I'm working on an inline 6 Jeep for a friend. But I have a problem. The symtoms are high temperatures and smoking while driving. It also likes to rev up at start every once and a while and will stall at lights.
I did a compression test, and all the cylinders were good.
What else do I look for? I'm not that great at diagnosing this problem.
Can a blown head gasket still have good compression in the cylinders?
What other test do I perform? Also, how do I check the cooling system for problems and leaks?
Thanks for any input you have.

 

[QBstang87]

cracked head? we just had one in the shop, showed good compressoin across all cylinders, pulled the valve cover and found the crack. check into that. blown head gasket may do it too, how does the coolant and oil look?

 

[proxses]

Not checked the coolant or oil yet. Going to soon.
Where should I look for a crack? What part of the head would it likely occur?
I also heard the exhaust manifold like to crack. But I'm sure that's unrelated.

 

[QBstang87]

the exhaust manifold studs definately like to crack, and we do replace a good few manifolds themselves too, so i guess you could say that. the head on the jeep we did was just cracked across the casting in between two cylinders, i think 3 and 4. it had built up grime and **** and made it pretty easy to spot. the jeep had came from a gas station who mis diagnosed it 3 times. once, said it was overheating, put radiator in. 2nd time, same thing, another new radiator. 3rd time, new radiator cap. then they finally brought it to one of our techs as a side job.

 

[QBstang87]

jeeps are speed density vechicles as well...so a cracked head could cause a vaccum leak and throw the idle off.