What is your coolant to water ratio? If not properly mixed such that there is a lot of coolant, it will actually reverse the effects you are going for and may cause overheating.

 

Only thing I can think of is maybe your surpentine belt is slipping instead of turning the water pump? Perhaps the pump bearing is starting to seize causing it to slip instead of turn? I would assume your belt wouldn't last long doing this so this is totally a stab in the dark lol

 

His water pump is drivin by timing belt not serpentine belt. It sounds to me like a fan or pump problem. Im not sure if your temp guage and fans share a coolant temp sensor but if not then it could be at fault.

 

What is your coolant to water ratio? If not properly mixed such that there is a lot of coolant, it will actually reverse the effects you are going for and may cause overheating.

I'm using pre-mixed coolant, so that shouldn't be an issue.

Only thing I can think of is maybe your surpentine belt is slipping instead of turning the water pump? Perhaps the pump bearing is starting to seize causing it to slip instead of turn? I would assume your belt wouldn't last long doing this so this is totally a stab in the dark lol

So you think it's cool enough while I'm driving without the water pump working properly but the heat becomes an issue while idling?

 

So you think it's cool enough while I'm driving without the water pump working properly but the heat becomes an issue while idling?

This could be the case because as you drive you are pushing more air into the engine bay through the front grills. Coming to a stop you stop that air flow. i would have your radiator, radiator fan, and water pump inspected. Have you done the 60K maintenance? I just had it done on my car and they said my water pump was seized and had to replace it. I was having similar issues to you.

 

Do your rad fans turn on?

 

Take off the little engine plastic piece over the rad and make sure it's not cracked. My 03 had a 9" crack on the thing 3 months ago. Also check your heater hoses *they go from the back of the engine to your firewall* and make sure there's no leaks.

Also, is your coolant nice and clear/clean? Not at all milky?

 

Could be air in the cooling system, your fans could be parts of the problem, depending on you miles may be in need of timing belt and new water pump.

 

Ok, so I haven't noticed anything leaking or cracked, although I honestly haven't done too rigorous testing, just looking around after I ran it for awhile. Reading on here, your replies, and talking some friends it would seem the most likely culprit is the water pump. Is there an easy way to test that being the case? Also, how hard is it to replace one if I get the part myself? I'm no expert, but I've done some things like this before (replaced the thermostat, my exhaust, etc). Thanks!

 

Make sure you bleed air out of coolant system before buying a water pump since it's free. How many miles on your car?

 

Ahh, I just noticed no one has mentioned fuses. Check your fuse box for your Rad Fans and make sure that you don't have a blown fuse/relay. Probably not the issue, but if the car is heating up while you're idling that could be a cause.

As for the water pump, it's not a quick change. Costly to have it replaced at a shop, as its basically like doing a timing belt job. Before that, i would do what dlanes recommends and burp the system (run the car when cold for about 10 - 15 minutes with the rad cap off)

 

Turn your A/C on. If your fans kick in, you at least know the fans still work. The fan temp sensor may be faulty, but as other's have said, check your fuses first. It definitely sounds like the fans to me.

 

have your guys tired using coolant?

 

The op talks about that in his post if you didnt read it

 

I have 87k miles on my car. I bought it at 67k and I'm not sure if the 60k maintenance was done no it, although it was kept in pretty good condition. Tomorrow morning I'll try burping it and check on the fans and fuses. Thanks and I'll keep ya posted!

 

"Burping" the cooling system is a thing of the past or a fallacy on modern cars. Most newer thermostats already have a bleed hole incorporated into them. The only cars I've ever known where you intentionally had to burp the system was some of the very old inline sixes. But even there, burping them can be eliminated by drilling a 1/8ths inch hole in the thermostat.

I still think it's the fans/relay/sensor/fuse due to the fact that it DOESN'T cool when not moving and DOES when moving. That to me says that the only problem is lack of airflow.

 

sounds like a bad coolant temp sensor to me

 

Hey, thanks for all the suggestions and sorry I forgot to reply back. I just wanted to post what the problem was for posterity's sake: it just needed to be burped. After burping it and adding a little more coolant, everything was kosher. Thanks again!