overheating when crusing.. please help
 

My car keeps overheating even when not boosting, just cruising on the highway at 2500 rpm. I just replaced the rad cap and thermostat and bled system. I noticed that the lower rad hose is usually cold, but sometimes it gets warm. Upper hose is hot. I didn't see any coolant in the oil or oil in coolant. The fan works and sometimes my heat gets cooler and then gets hot again. Also the temp gauge goes full hot and then drops back down sometimes. Will usally cool down if i just put the car in neutral for alittle. I have a cometic headgasket and arp head studs with about 4000 miles on the engine. I boost about 8 psi. Has been overheating for a few weeks. Any help is greatly appreciated.

Re:overheating when crusing.. please help
 

You might have finally lost your water pump. If one hose is cold it sounds like you arn't getting circulation.

Re:overheating when crusing.. please help
 

I would hope its not the pump. Its got less than 5000 miles on it.

Re:overheating when crusing.. please help
 

Have you ever had your system flushed? Maybe you have some blockage? Might want to flush the radiator too.

Re:overheating when crusing.. please help
 

you thermostat is probly goin out on you. just change it and see if it keeps happening

Re:overheating when crusing.. please help
 

crx2fast- I just replaced the thermostat and rad cap before I posted. I thought it was the thermostat, but replacing it didn't help. Do you think this one is bad also?

95RedEX- I've never actually had it flushed with a machine or anything but when I built the engine and installed it about 5000 miles ago I made sure everything was clean but I don't remember flushing the radiator. I'm gonna do that now.

Thanks for the help guys. Keep it coming

Re:overheating when crusing.. please help
 

mgiht be the radiator, check the bottom hose for any leaks, if not, i'd put money on the water pump, maybe the timing is off and its making the pump act weird

Re:overheating when crusing.. please help
 

i got 5 bucks on the headgasket is shot

ive been there a few times

Re:overheating when crusing.. please help
 

would bad rings be another culprit?

I am about to rip apart my b16, and it does the occasional heat up thing.

Re:overheating when crusing.. please help
 

Well I'm gonna cancel out the radiator as being a cause. Just flushed it and it flows great. Took the car out for 10 mins, boosted once for like 3 seconds got off the gas and cruised and it overheated again. Pulled over, lost my heat. Lower rad hose was cold. I let my car cool down, then drove home and didn't boost. The temp was about 3/4 on the gauge by the time I got home. I love it! I'm thinking its the pump, but I don't know how its not pumping.