still overheating

[csbuckn]

so the gaskets are on correctly now and we have the right water pump but it still is overheating. we took the therm out and bypassed the heater core and still the same. this is gonna drive me crazy. when we start the burb, Alot of pressure builds up in the upper radiator hose and it overheats(even with the therm out) and the lower radiator hose stays cold. when we open radiator cap, the pressure goes away and the temp will stay hot but not overheating. we just did head gaskets and if the gaskets are symetrical then i cant fiqure out what is wrong. so thats new radiator, therm, water pump, gaskets all around.

Now when i feel the radiator all the way up, it doesnt want to stay running. anybody want to buy this thing 700

 

[csbuckn]

I also heard something about a vapor lock?

 

[80' 427]

Did you have the heads crack checked? How about deck strightness?

 

[csbuckn]

i didnt have the heads checked and have no idea what deck strightness is but if the heads were cracked, wouldnt it overheat at all times? this thing only heats up when the radiator cap is on tight. With it off, the heat stays down until i drive it for about 5 minutes then it overheats. Also when i fill the radiator up with fluid, it doesnt want to start and the fluid jumps 2 feet in the air when i try to start it with the cap off.

 

[Jason4x4]

i didnt have the heads checked Also when i fill the radiator up with fluid, it doesnt want to start and the fluid jumps 2 feet in the air when i try to start it with the cap off.

Sounds like you got a blown head gasket, Did you get the heads checked at all when you pulled them off? A blown head gasket will push coolant out of the radiator like you described.

 

[4xcrazy]

Yup, after reading your last post, i am willing to bet the headgasket is leaking pretty good into a cylinder..

says it doesn't want to start if he fills the radiator all the way up, maybe similar to mine, where the coolant was leaking through the bad gasket, into the cylinder, and hydrolocking...

The other thing you say, it blows the coolant out while it's running, i had a 3.1 motor that are notorious for blowing #1 cylinder headgaskets, and it did this same exact thing,,,it would pressurize the radiator before the motor was even hot...majorly.

 

[fried_guy]

Checked for clogged radiator?

Pressure check the system, that'll tell you if you have a leak somewhere.