i noticed that my car would overheat at idle about a month or two ago. it would cool down after a minute of driving though. now it seems to do it more, especially if i push the motor hard. i figured it was the thermostat, which i replaced today, but the car still overheats. the weird thing is that as soon as the temp. guage goes past the halfway point(usually) 3 or 4 bars, i will turn the car off and if i imediatly restart the car, the guage will stay at the halfway mark. i would think that if the car was overheating before i turned it off, it should still be hot when i restart it 5 or 10 seconds later. the only mods that i have are cai and exhaust which i know are not the cause of overheating. i am on a tight budget, i am thinking about getting my radiator cleaned out, maybe that might help. both of the fans work also and the coolant is full. i do not leak any coolant either, and the coolant isnt tainted with oil. sorry that this is so long. any help will be greatly appreciated!!!!

 

year model of car.

did you bleed the coolant system of air through the bleeder valve??

 

my bad!!! its a 96 prelude s. as far as bleeding the cooling system, i drained about 1/8 of a gallon out of the radiator draincock, but i read my repair manual right now and and it says there is a bleeder valve on therm. housing. i will try that today. do air pockets really make that much of a differance? i asked my dad and he said no?

 

Try replacing the radiator cap.

Sounds trivial and stupid, i know... but I was having the exact same problem with my eclipse. At a stoplight, or just idle, the car would begin to overheat, but it would quickly subside as soon as I revved it or began to move.

Turns out... the radiator cap was leaky, and the cooling system was losing pressure and some fluid. Easy do-it-yourself'er, or 20 bucks at pepboys. Worst case scenario, it isn't it, and you have a pretty new cap.

yeah... air pockets will definitley make that difference... screws up the pressure gradient needed to keep the fluid moving..

 

ACTUALLY, I WAS THINKING ABOUT GETTING A NEW CAP. THE CAP LOOKS PRETTY OLD, PROBABLY FACTORY ORIGINAL.

I BLED THE COOLING SYSTEM YESTERDAY, RAN FINE FOR ABOUT 45 MIN. I WAS STUCK AT A LONG LIGHT AND THE GUAGE ROSE A NOTCH HIGHER THAN HALFWAY. BUT I RAN INTO A DIFFERANT PROBLEM LAST NIGHT, THE TEMP. SKYROCKETED AFTER ABOUT 5 MINUTES OF DRIVING. THERMOSTSAT PROBLEM I GUESS, THE RADIATOR HOSE THAT CONNECTS TO IT WAS LUKE WARM BUT THE UPPER RADIATOR HOSE WAS BOILING. I JUST REPLACED THE THERMOSTAT TOO. THANKS FOR THE ADVICE, I WILL BE SPENDING ALL DAY TODAY FIXING MY CAR!!!!!

 

Is the thermostat "aftermarket"?I put in an aftermarket one in my car when it was overheateing and it lasted for 3 days!!!!After that I put in a Honda one and haven't had a problem since and that was 2 years ago.Talk about frustrating though.:madfawk:

 

WOW, I BEAT YOU BY ABOUT 2 DAYS! I PUT IN A CHECKER AUTO PARTS POS, AND I HAD TO TAKE IT OUT BECAUSE MY CAR WAS BURNING UP LAST NIGHT.IT LASTED FOR ONE DAY. I WAS JUST GONNA RUN WITHOUT A THERMOSTAT UNTIL NEXT PAYDAY, I LIVE IN PHOENIX AND ITS HOT AS HELL SO I FIGURED IT WOULD B OKAY. I STILL HAVE TIME TO RUN TO HONDA TODAY AND PICK ONE UP, SHOULD I? THANKS FOR THE HELP.

 

i cut out the middle of my stock thermostat =)

 

im gonna just buy another thermostat next week, but if my car still overheats, i may have to try that. the wierd thing is, after i took the thermostat out, i drove the hell out of my car trying to get it to overheat, it was mid afternoon and boiling hot. i even drove around in third gear for 3 miles, and went to mcdonalds and waited in the drive thru. my guage didnt budge. i went out later that night, and my guage went up a notch, wtf! im gonna get a new rad. cap soon, thats probably part of the problem. anyways, thanks for all of the advice everbody!!!

 

My car also overheats. Took it to a mechanic and he cleaned my radiator, replaced the thermostat (after-market) and topped off the coolant. Still overheats. Could my engine block be clogged with deposits/gunk? Any advice?