[rhartman52]

I own a 2015 Chevy Malibu and I've noticed the cooling fans run from the moment I start the car and keep running for 3-5 after shutting the car off. I replaced the coolant temperature sensor and that didn't fix the problem. But let me backup a bit. This problem seems to have started one day when I started the car and the display on the instrument panel said engine was overheating and to let it idle or something to that effect. But I knew the engine wasn't overheating because it was cold when I started it and the message appeared right away, before the engine was even warmed up. This "overheated engine" display went on for the next hour or so as I drove from place to place trying to find someone to work on it. Then it just stopped. However, I noticed the temp gauge wasn't working, I had no a/c, and my check engine light was now on. After a few days, I disconnected the ground from the battery and reconnected it and this when routine started over again. Next I replaced the coolant temperature sensor and that didn't change anything. Any ideas/advice on how to fix this issue?

 

[DrivenDaily]

Step 1: Scan for codes.

Your symptoms sound a lot like a failed ECT sensor.

If the computer expects the reported temp to be in a certain range and it's not, it acts like the ECT sensor has failed (and it might have), and turns the fans on continuously to ensure that the engine has the best chance of not overheating.

But scan the codes before lighting off the parts cannon. It could be a wire or a plug.

 

[rhartman52]

I actually took the car in to the auto repair shop and they ran a diagnostic check. Here's their finding:

Coolant housing on rear of cylinder head is leaking causing coolant level to be low and making cooling fans to run constantly.

I don't think this is the problem. Before I took the car to the shop, I checked the coolant level and it looked fine. After leaving the shop, I checked it again, noting it was full. I've checked numerous times since then and the level of the coolant in the coolant reservoir has not moved.

 

[rhartman52]

I should add that there was no work done on the car other than the diagnostic check. Although the shop said I had a coolant leak, I didn't have them fix it. In my opinion, it wasn't and still isn't leaking.