Recently with all this hot/humid weather, my car has been overheating randomly. I changed the radiator last Monday because my stock one looked a little beat. I bled the coolant and all was well until last night. I drove for about 5 mins to the store and it was at 2 bars (normal halfway point). I come back and hear the fan turned on, but the gauge is at 3 bars. So I drive off and about 10 seconds later the gauge goes back down.

So tonight I check to see if the fan motor/relay/harness is working and it is. I let the car idle for 20 mins and the temp is perfect, the fan even kicks on for about 10 seconds and turns off, but the temp doesnt change at all. So I drive to my gf's house (about 20 miles) and everything is fine. We go to mcdonalds drive thru and while idling the temp gauge shoots up to the red. I turn the car off and turn it to the 'on' position and the gauge is back at halfway. I drive another 3 miles and let it idle a bit and its fine.

Anyone know what it could be? I know the temp gauge is a dummy gauge but I wont be able to get a real temp gauge for another couple of days. I want to say the thermostat works because the bottom radiator hose is hot and the fan kicks in. Maybe its a bad ground somewhere?

 

Could be a bunch of things including....
-clogged radiator
-faulty thermostat
-headgasket (not likely)
-small leak....causing the coolant level to be low
-or it could be a wore out radiator cap which is what solved this problem for me...

good luck and let us know how it turns out.

 

I hope its not a clogged radiator cus i just bought a new one last week. Radiator cap is new as well and the coolant level doesnt seem to be dropping as ive been keeping an eye on it. I'm leaning towards the thermostat and REALLY hoping its not a headgasket (though no symptoms seem to point towards a blown headgasket). It's annoying because the problem isn't consistent, which is why im leaning towards air bubbles in the system.

I just got home from work, about 10 miles, and ran it pretty hard on the highway and let it idle once i got home. It idle'd fine and the fan even turned on after about 5 mins and stayed on for about 10 seconds. The temp gauge stayed perfectly at halfway point. Guess i'll flush out the system completely and rebleed cus i'm stumped

 

If it seems like the guage is not accurate check the engine ground that connects the chassis to the drivers side engine mount. Mine wasnt hooked up after my swap and it was causing the temp gauge to act really funny.

 

yes definately check the grounds, mine did the same thing.

 

Just looked and saw my ground wire on the valve cover to the chassis/engine mount is hooked up. I'll probably clean it up/sand the area down so its metal. Damn this heat!

 

change thermostat?

 

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gonna test it out this weekend in boiling water to make sure it works. just dont wanna go out and get one and not fix my problem

 

Not saying that your ground is the problem but even if I hooked up a 8 gauge wire from my valve cover to the chassis it still didnt work. I had to run a 4 guage from the actuall engine mount to the chassis and from the valve cover to the chassi. Really weird but thats how it worked for me. Do you fans come on?

 

when i had this problem it was my grounds so i changed them and it fixed it but if thats not it try the thermostat

 

yeah the fans come on. guess i'll switch out the ground wires with some thicker gauge wires.