c4 overheat @idle
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Intermediate
Joined: Jan 2005
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From: ville platte Louisiana
c4 overheat @idle
Morning all.. Question..94 c4 overheating at idle.Fan not coming on except with ac.Fuses good.coolant full.Cools down some when driving.I'm guessing coolant fan sensor or relay?Can you help with locations? Thanks! Steve
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From: Rolla Missouri
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Originally Posted by scbmcglynn
Morning all.. Question..94 c4 overheating at idle.Fan not coming on except with ac.Fuses good.coolant full.Cools down some when driving.I'm guessing coolant fan sensor or relay?Can you help with locations? Thanks! Steve
By overheating, what temps do you mean? I ask this because I thought I had the same problem. I was afraid to let it idle very long without the a/c on. I didn't think my fans were working. Turns out everything is working just like it is supposed too. The fans will not come on until around 227 or so. I have learned through reading this forum that these are normal temps at idle for these cars.
Now if you are really seeing temps way above this, then yes it needs to be looked into. I believe the fan relays are right there on the drivers side of the radiator shroud.
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From: Rolla Missouri
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Yes, the anolog gauge will be almost to the end by the time the fans come on. More Important, what is the actual temp? What does the digital gauge read?
Melting Slicks
Joined: Oct 2004
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From: Austin Texas
Originally Posted by scbmcglynn
Thanks for the tip on looking at the digital guage.You're right.Fan comes on at 228,but the analog guage shows almost 260.I guess digtal is more acurate.
260 is a bit too HOT! Check for debris which gets sucked up between your condensor and radiator.
Safety Car
Joined: Feb 2002
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From: Sun City West Az
Originally Posted by scbmcglynn
Thanks for the tip on looking at the digital guage.You're right.Fan comes on at 228,but the analog guage shows almost 260.I guess digtal is more acurate.
Your engine could very well be getting hot as shown by the analog as the sensor for that is screwed into the pass side head. Your coolant, as sensed by the CTS in the water pump, may be "cooler" than your head temps. Since the ECM is turning on the fan(s) when the CTS is @226-228, the engine itself can be hotter. 260 is to hot and you may have something going on here.
Last edited by ittlfly; Nov 26, 2005 at 06:01 PM.
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I'm pretty sure primary for the '94 is 217 and secondary is 226 (a/c off)and since the fans are coming on with a/c, the Relays are good (as well as the driver circuitry back to the ECM. I'd check it with a scanner to verify that the ECM is grounding the relays at these temps, speed below 35 to 40 mph. With that confirmed, and if it's overheating (most should be close to the thermostat at cruise so with the scanner hooked up, you can verify what the gages are or aren't telling you). If the fans are within specs but it's overheating then look for: a bum thermostat, dirty coolant or a plugged up radiator, restricted air flow, (or high a/c condensor pressure if the problem is worse with the a/c on). If the fans aren't coming on within specs, then suspect the ECM. Changing the programming or adding a manual fan switch isn't going to do you much good until you know if it's working as designed.
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Joined: Apr 2003
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From: VA
Stock fan temps on my 94 were 219 and 228 oF
If you are not getting any fans until 228 then you have a problem with the primary fan. Do both fans come on with the AC or just one?
I suspect you have a faulty sender for the analog guage.
If it's really at 260 I think you'll hear some boiling in the header tank.
As mentioned you can get the fans reprogrammed to come on sooner.
What's the temp on the highway?
If you are not getting any fans until 228 then you have a problem with the primary fan. Do both fans come on with the AC or just one?
I suspect you have a faulty sender for the analog guage.
If it's really at 260 I think you'll hear some boiling in the header tank.
As mentioned you can get the fans reprogrammed to come on sooner.
What's the temp on the highway?
