Overheating at idle/Fine when driving

boitano928 · #1 (**permalink**) 08-12-2008, 08:54 PM

I searched the forum and couln't find any post with the problem i'm having but apolagize in advance if it's posted somewere. Any way - every once in awhile while i'm driving and stopped at a traffic light or in traffic my temp. gauge will move all the way to hot. When i start moving again it drops right back down to the normal temp. My coolant level is fine and I can't figure out why this would happen. The only light on is my check engine but that on probally cause I have headers installed. It doesn't happen all the time which makes it weirder to me. I was thinking it could be my headers creating a lot of heat and while the car idles the cooling system isn't cooling the engine enough but don't know if that would be it. Can anyone help me out with this problem. Any suggestions would be a help. Thanks.

**jserrano** · #2 (**permalink**) 08-12-2008, 11:02 PM

Be careful driving around like that. If the engine is really heating up then the radiator fans should be kicking ON. Check them when the problem reoccurs. If they don't come on then turn the AC to ON in the meantime to get the radiator fans cooling the system. If that still doesn't cause the fans to come ON then you're in deep shit.

bradb · #3 (**permalink**) 08-18-2008, 04:37 PM

why whould he be in deep shit? if the fans cut on and it still over heating more then likey its the thermostat and that only takes like 15 minutes to put iton an the part is like 15 bucks.

**jserrano** · #4 (**permalink**) 08-18-2008, 09:10 PM

Quote:

Originally Posted by bradb

why whould he be in deep shit? if the fans cut on and it still over heating more then likey its the thermostat and that only takes like 15 minutes to put iton an the part is like 15 bucks.

Re-read what OP is saying. His temp gauge is showing the engine overheating while idling but good while driving. What does that mean? That coolant must be circulating through the radiator and is getting cooled down by the headwind. If the thermostat was indeed stuck shut then your engine will not be cooling down at any time - except when the cooling fans were running. In which case you'll have what is called an "engine running too hot" condition.

Now keep in mind that our temp gauge does not work linearly. It will sit in the midrange point even while the engine is burning up. Luckily an engine coolant temperature sensor is sensing the actual coolant temperature and feeding that over to the ECU. If the ECU senses about 203 degrees F it should turn on the cooling fans while the water temp gauge remains at midrange. So, are the fans kicking ON? If not, then either the water temp gauge is lying or the cooling fan circuit has a problem. One way to test that, and to also keep the engine cooled off some, is to turn the AC switch ON. And if that still hasn't caused the fans to come ON then he is indeed in deep caca. I'm more inclined to think though that the temp gauge is lying. But OP hasn't responded to confirm.

bradb · #5 (**permalink**) 08-18-2008, 11:44 PM

well on my cavalier it did he same thing and it was the thermostat thats why i said that but i get what your saying.

Asleep · #6 (**permalink**) 08-19-2008, 12:17 AM

could be a blocked radiator as well.
no airflow at a stop will be magnified by a clogged rad.
could be something as simple as leaves and debris or clogged internally.
either way, a coolant system flush and checkup sounds like its in order.

boitano928 · #7 (**permalink**) 08-19-2008, 02:22 AM

Thanks for the help guys. I'm going to check to see if the radiator is clogged,a nd those sensers. Probally flush the radiator to.

cwhit122 · #8 (**permalink**) 08-19-2008, 07:18 PM

i had the same problem with my altima it was a bad radiator and my fans were not turning on when the ac was on, so i got those replaced as well with a dedicated switch for them to turn on at all times. Make sure also that you dont have a coolant leak, that could also cause your car to overheat at idle. Hope this helps

vipervic · #9 (**permalink**) 08-19-2008, 08:45 PM

Quote:

Originally Posted by boitano928

I searched the forum and couln't find any post with the problem i'm having but apolagize in advance if it's posted somewere. Any way - every once in awhile while i'm driving and stopped at a traffic light or in traffic my temp. gauge will move all the way to hot. When i start moving again it drops right back down to the normal temp. My coolant level is fine and I can't figure out why this would happen. The only light on is my check engine but that on probally cause I have headers installed. It doesn't happen all the time which makes it weirder to me. I was thinking it could be my headers creating a lot of heat and while the car idles the cooling system isn't cooling the engine enough but don't know if that would be it. Can anyone help me out with this problem. Any suggestions would be a help. Thanks.

sounds like something clogged in the radiator for that to do that