Ok the whole story: B18c runs normal temp unless i really beat on the car. Then the car will stay cool until i let the rpm drop. After that I turn on the heater trying to keep it from over heating, but the heater blows cold. Then the gauge starts doing this crazy thing going from reg temp to 3/4 gauge, then back up. When i stop and check it the hoses are hard and i blew coolant out of the resivior. I have ARP's and a cometic. The head was decked. I have tryed gutting the thermostat, it still does the same thing but just not as hot. I have tried my friends radiator, same issue.I have replaced the water pump, nothing. I am running a dual core with slim fan and shroud. The car is on e85 with a/f under boost in the 10.8-11.2 area. We have done a chem test for carbons in the coolant, and none so it doesnt look like a HG but im open to any suggestions.

 

Is the valve on the heater core line working propery? Have you flushed the heater core?

 

I have not flushed the heater core, but if i dont beat on it and let it warm up normaly the heater works fine. Also after a while of the gauge saying its hot then cold then hot again then the heater will start blowing hot like normal. Do you think i should bypass the heater core then see what happens?

 

I might be way off, but when my head gasket was slighty blown my heater would stop heating for a bit. Im guessing air was getting in the line or something, so are you losing water too?

 

I had a similar situation in which the problem was a very small failure in the head gasket. I replaced it and resolved the problem.

 

def air in the cooling system to make the gauge jump around..

 

stupid question, but when you "bled" the cooling system, you had the heater on, right?

 

I'm with him. It does sound like air is in the system. Remember to cut your heat on full when adding/bleeding the cooling system. Keep adding coolant while the relief valve on the thermostat housing (depending on motor) is open. Let it bleed out air until the car is 100% warmed up, or when the rad. fan cuts on.

 

rev engine and squeeze hoses to force air out. usually 3 fan cycles or 15 mins should do ya

 

You are exactly correct it should, but it doesnt. I have bleed the system till the fan cycles but it takes alot longer due to a gutted thermostat. I do let the fan cycle several times. You are not reading the whole story. I AM PUSHING COOLANT OUT OF MY RESIVIOR! This doesnt happen with out the introduction of something else like air. I am wondering what else it could be other than a head gasket. I HAVE DONE A CHEM TEST FOR CARBONS IN THE COOLANT AND THERE ARE NONE. I just want to make sure that i dont pull the head for no reason. I have also checked the Intake manifold gasket and replaced it twice but that doesnt seem to be the issue.

 

damn man, i cant think of anything.. jeez u did alot of replacing. sorry dood.

 

Im kinda thinking GOD hates me for making that much power on corn and stock bottom end

 

its just the little demons that surface when u mod cars.. we all get em sooner or later

 

Any one else have any suggestions? Or should i just pull the head and do a new gasket

 

well im not sure how much this is relevant, but this was happening in my eclipse, the heater blowing cold air, sort of overheating. all we did was take the hose out of the heater core and loop it back into the system just elimating the heater core all together. I never drove it in the winter so I could give a **** about the heat, and it solved the probs for me.