AMC 150 I4 - cracked head???

[stockCJ7]

I recently purchased a 1986 CJ7 with the AMC 150 I4 which is overheating. PO replaced water pump so it's brand new, I pulled and checked the thermostat - it's fine, the fan runs very strong so I assume the fan clutch is OK, but it's overheating with water pouring out of the overflow tube after about 15 minutes at idle. Got scared I had a cracked head. Drained oil and it's not milky. Would oil definitely be milky if the head was cracked? What about if it had a blown head gasket and not a cracked head? I'm no mechanic (unfortunately) so looking for help diagnosing my problem. Thanks!!!

 

[caveman]

It depends on where the head is cracked or the gasket has failed. It sounds like whatever the problem it is, it's between the combustion chamber and the cooling ports. If you had water in the oil, it would be between the water and oil ports. If you realy think thats the problem, You need to pull the head. It sounds to me that you might be right.

 

[mstar]

If it where a crack or gasket failure that was leaking into cooling system you could test with a Stant Cooling System Tester.You just attach tester to radiator and then power brake engine to simulate a load.If pressure rises
rapidly you will know there is a problem.The Stant testers are about $100.00 ,but I have seen them on E-bay for a fourth of that.Very handy tool to have.It also has a pump to pressure test for leaks as I was doing in the photo. mike

 

[stockCJ7]

Thanks. I drained the oil last night and it looks fine. I have ordered a combustion leak tester on Amazon for about $50. (Pour the liquid in to see if it turns colors.) Waiting for it to show up. Hoping this radiator just clogged. I'll know when the tester arrives.

 

[mtnwhlr]

Are you sure you don't have a pluged radatior? I would looking at the cooling system instead of the head.

 

[mstar]

I guess he didn't like my idea. He could have just sent me the $50.00
it would have the same result. mike

 

[stockCJ7]

I guess he didn't like my idea. He could have just sent me the $50.00
it would have the same result. mike

How's that? u gonna lend me yours?