[Turk 182]

Engine overheating at low RPMs

I have a 2003 - 2.3 liter Mazda6. When I am driving, or anytime the RPMs are about 2,000 or above for that matter, everything is fine. However, when I idle, I get 2 problems. For about ten minutes everything is fine, but after ten minutes, warm air starts to come out of the A/C even when it is set to the coldest setting, and much more importantly, the engine temperature starts to rise. The temperature gauge starts climbing and even goes into the red. The funny thing is, when I'm in park and this happens, if I press the gas to bring the RPMs up to about 2,000 and hold for a minute, the engine temp goes back to normal and the A/C becomes cool again. If I take my foot off the gas and let the RPMs go back to idle at 900 RPMs, the same problem occurs after about 5 minutes.

Any ideas what could cause this?

 

[thanh]

I am curious weather if it's a thermostat issue. It's odd because it only happens at low rpm. Quite possibly the increase pressure of the water at higher rpm might be forcing beyond a bad thermostat.


Remove the thermostat and see if it keeps the car cool for a long time. If it does then it might definitely be it. Not hard to remove and replace at all.

 

[DiscoBerry]

I would check the easy things first, make sure that the cooling fan comes on and that the radiator isnt clogged with grass, dirt or mcdonalds wrappers.

 

[MrTea]

lol, wtf do you do to your radiator man??

 

[MonoxideChild]

sounds like you REALLY need to check your radiator fluid.

 

[Egierda]

I'm saying that your water pump is on it's way out. Is the water pump on the i4 driven off the accessory belt? If so, that would explain why it's still providing adequate cooling but only at higher RPMs.

 

[DiscoBerry]

you can find some interesting things in peoples radiators last time i changed one on a 1997 chevy pickup i found a dead bird

 

[MonoxideChild]

i did a waterpump on a GM 3.1 a few years ago. and when i pulled the waterpump, there was a big dead worm wrapped up in the impeller. lol. i brought it with to the parts store just to show them. they had never even seen such a thing.

 

[e4w]

i'd def get the radiator flushed+replace the thermostat from your symptoms.

 

[Egierda]

It has to be an RPM-dependent issue based on the symptoms describing in the OP. He can even be bloody STOPPED and hold the RPMs up and the temp comes back down. I'm still going with water pump, slipping belt on the water pump pulley or something regarding the efficiency of coolant circulation...100%.

 

[e4w]

hmm, a 7yr old car without posting miles, maintenance on cooling system, and other details besides the high rpm for temp gauge to drop. from my past experience with such problems, i'd go with my 1st comment. he didn't say anything about a belt squeal, water pump leak, etc.. when the water pump is considered bad is when the seal leaks and/or the bearings go bad.

this aint no right or wrong competition, im just posting from experience POTNA! get it together E! LMAO

 

[Turk 182]

Thanks for the replies. The car has 83,000 miles on it. I checked the radiator fluid level and its fine, the fan is turning even when the engine is getting hot at lower RPMs, and there isn't anything blocking the radiator that I can see - no dead birds. I'll keep you posted on what it turns out to be.