how do u know if ur thermostat is goin bad cause when i am driving my da its stays on cold then when i sit at a light for a few mins or so it will start to heat up but then when i am driving it wants to get cold again so i was wondering how do u know if its bad.

 

check see if your cooling fans working...could be your temp switch...or thermostat...

 

my da does the same thing too, i havnt figured it out yet but it does it if my fans are running as well. i hooked them up to run with the switch on just to eliminate that and it still heats up

 

Agreed, but it's unlikely that the fan switch is bad unless there is a clearly visible sign like the fans staying on all the time or never turning on at all. In your case a bad fan temp switch should be very easy to spot because the fans will be running pretty much all the time. The usual failure mode is that they don't turn the fans on at all and the engine overheats.

A stuck (open) thermostat is the likely cause. It should eventually come up to temp if you drive it around and then let it idle in your driveway for while, and the fans shouldn't come on until it comes up to temp. If they do, I'd look instead at the temp gauge sending unit. The engine might come up to temp fine but the gauge might be telling you otherwise.

I think my car has a slightly stuck open thermostat, it takes a long time to warm up but regulates temp perfectly fine once it does.. It was -6 degF here today in CO, so I didn't have very much heat for a looong time. Bigass Koyo aluminum radiator isn't helping the damn engine warm up any faster with a slightly stuck thermostat, that's for sure.

 

just replace the thermostat. it doesn't cost much and is easy to do. i had an integra that never seemed to warm up consistently and this was the problem.