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Overheating during extended idle

30638 Views 28 Replies 16 Participants Last post by  Sunline Fan
Cruze has 42k miles on it. The last 3 days in a row my car overheats while idling in heavy traffic. It did this with a/c off. Car went back to normal operating temp once I was moving. Any thought to what part is going bad?
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What's meant by Overheating? You mean the radiator fan came on? Indicator lights?

Check the coolant and add to bottle, you may have an air bubble in the coolant system, or you may have a leak.

Drips on the ground?

Is this a 1.4L or 1.8L?

Sorry for all the questions, but we need more information to help you.
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A few possibilities here, thermostat, water pump, cooling fans not operating or operating when they should...low coolant level...radiator blockage (odd at this age however)....
Cruze has 42k miles on it. The last 3 days in a row my car overheats while idling in heavy traffic. It did this with a/c off. Car went back to normal operating temp once I was moving. Any thought to what part is going bad?
Hello Farmer,

Have you had the chance to take your Cruze into then dealership for diagnosis? They will be in the best position to look into this further for you. If you need any additional assistance, please feel free to send me a private message here including your VIN, current mileage, contact information and a preferred dealership. Looking forward to hearing from you!

Patsy G
Chevrolet Customer Care
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Definitely check the coolant level, but the description makes me think it's a bad fan.

But first: Make sure it's really overheating. It's possible with the A/C off the computer will allow the car to warm up a little more before kicking in the fan. My old car would sit rock steady at 1/2 if the A/C was on, but if it was off it would go up to 3/4 before the fan would kick in and cool it back down to 1/2. I haven't turned off the A/C in my Cruze long enough to see what it does.
Definitely check the coolant level, but the description makes me think it's a bad fan.

But first: Make sure it's really overheating. It's possible with the A/C off the computer will allow the car to warm up a little more before kicking in the fan. My old car would sit rock steady at 1/2 if the A/C was on, but if it was off it would go up to 3/4 before the fan would kick in and cool it back down to 1/2. I haven't turned off the A/C in my Cruze long enough to see what it does.
From what I've seen, it does allow the engine to warm up a little more...but only from just below the last hash before middle to on top of the last has before middle.


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A/c off warning light and idle engine warning light.
Coolant level is normal; no leaks.
1.4 engine
No engine fan running when temp peaks.
A/C off due to high temp sounds like T Stat. What year are you? if 11-12 you can see the digital temps.
A/C off due to high temp sounds like T Stat. What year are you? if 11-12 you can see the digital temps.
Except it cools off when he gets moving again.

I'd check to make sure the fan spins freely and nothing is jamming it. Otherwise it needs to get checked out. Looking at my service manual (2013), it's a 3-speed fan. The control system has 5 relays (KR20C, KR20D, KR20E, K20F, KR20P) and 3 fuses (F42, F45, F46). Given the complexity, it must have been designed by a intern as it seems needlessly complex.
The fan spins by hand but I haven't seen it move otherwise
Except it cools off when he gets moving again.

I'd check to make sure the fan spins freely and nothing is jamming it. Otherwise it needs to get checked out. Looking at my service manual (2013), it's a 3-speed fan. The control system has 5 relays (KR20C, KR20D, KR20E, K20F, KR20P) and 3 fuses (F42, F45, F46). Given the complexity, it must have been designed by a intern as it seems needlessly complex.
The fan spins by hand but I haven't seen it move otherwise
I also agree on the fan.
Does the fan come on with the AC? You might want to check the under hood fuse box for fuse 46 and relays 7, 9 and 13.
If none of the relays are bad, it's more than likely the fan. I miss my good 'ol e34 BMW which didn't have an electric fan. The fan was attached to the water pump, so it was always running.
The fan spins by hand but I haven't seen it move otherwise
As i think someone else said, turn on the A/C and pop the hood to check to see if the fan is running. If not, I'm thinking its your engine fan. Only other thing it could be with those symptoms is low coolant but you checked that already.
I'm not sure how the fan works internally, but given all the different relays, fuses, and 3-speed, it seems like it should be running at some speed. I think I'd inspect wiring to make sure something hasn't popped out, or has shorted out.

Personally, I'd troubleshoot it rather than throw parts at it and hope I'm right.
I tried running A/C with the hood up. Fan still isn't moving.
OK, there's a problem. I'm not sure what to suggest other than checking fuses under the hood. The circuit is complex enough that you'd need a wiring diagram and a test light to trace anything.
Auto part Engine Pipe Vehicle
I tested 46 fuse; it's still working. I tried running A/C again and the engine fan is running now. I took a pic of the coolant tank. Is this full or do I need to put it to the top line? There is an up arrow at the top line. My coolant is the middle line.
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Your Coolant reservior is Fine where IT is at !
Nice name, BTW, Farmer.
This sounds like an air bubble. There is more than one temperature sensor. One may be wet and reading correctly while another is dry and reading cool. I had a similar issue, except fan was running 24/7 at high RPM while temps were stable. This continued for a month, until temp started to spike.
Why didn't I put it in the shop? Because warranty is out and and was addressing a different issue (irrelevant info, sorry).
However, coolant level seemed fine, but had reached a level thresh hold when cool that allowed it to suck in air.
It is a sealed system, but "sealed" should be a term used loosely.

I was able to correct the issue by adding fluid and bleeding air.
When the car is cool, check and add fluid as necessary. leave cap off while car warms up to allow vapor to escape. fill to minimum when hot, if needed. Then, replace cap tightly.
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