I have 2005 Malibu LS and I recently noticed my engine temp was going up when my car is idle and goes down when driving searched a bit and found out it is most likely cause fans I checked my car got 2 radiator fans and they both don’t work right now but the thing is when I run my car’s AC (air conditioning) my car’s temp doesn’t go up no matter if I idle or not so I don’t know if it means some special case but maybe someone might point out why AC fixes the problem.
Mainly I was wondering why my both fans have stopped like are they connected to the same motor because them failing at the same time makes me think it might be a fuse ? some electrical issue ? or is it just 1 radiator fan motor running 2 fans ? Thanks to everyone who try to help to this case.
Turn on your a/c and open the hood. If your fans are running, there is nothing wrong with your fans. You fans are supposed to come on when the a/c is on or when the engine temp reaches a certain point.
There is something wrong with the system that turn on your fans because of engine temp.
I am not familiar with GM cars, so I don’t know what controls yours but it could be a temperature sensor, relay, fan controller (if used) or rarely the computer.
Yes I think you are right, if turning on AC supposed to turn on fans then it explains me running AC fixing the problem,as you said fans are not getting activated based on the engine temperature then whatever makes my car’s fans activate on a certain temp is broken, I will look it up thank you for the insight 
First, check the coolant level in the reservoir AND the radiator, too (When the vehicle is cold so you are not burned.).
Low coolant can cause those symptoms and could become catastrophic.
If the level is fine then proceed with diagnosing the fans/fan controls. If it’s not fine then fill and proceed to find out what caused it to become low. Consuming or leaking (externally or internally) is not normal.
Let us know what you find, please.
CSA
Coolant levels are fine and water pump and thermostat was replaced a year ago.
Overheating can be caused by a variety of things. So as long as the fans are spinning when they should be (i.e.e when the engine is showing signs of overheating) don’t just assume the problem is the fans. If you definitely narrow it down to the fans, on some vehicles the fans can be programmed by the computer to spin at different speeds. From what I’m seeing this is the case w/your Malibu. The power train control module controls relay 28 29 and 30 to select the fan speed. It’s either selected to be hi or lo speed, just two fan speed possibilities (besides “off”) in your case. So there could be something wrong w/all that.
Common sense says to first inspect the coolant level (in the radiator, not just the plastic overflow bottle) and to make sure the radiator grill isn’t clogged w/bugs etc.
I’d look at the relays and the coolant temp sensor. I have an 05 Sierra and went through an ordeal where the fans wouldn’t come on (with or without ac). From what I remember, the coolant temp sensor sends the signal to turn the fans on. It also comes on when the AC is turned on.
I’m fairly certain if you unplug the coolant temp sensor the fans will come on by default. So try that first (with AC off). If the fans come on, replace the temp sensor. If they do not come on with the temp sensor unplugged, swap like relays with the fan relays. If all of the relays are good and the fans are still not working with the temp sensor unplugged and AC off, the problem would be either with the wiring or the pcm (probably less likely).
I never figured my issue out. All relays were good, and the fans came on with the coolant temp sensor unplugged (if I recall correctly). The fans also worked when wired direct to 12 volts. I finally gave up and took it to a shop. They never found the issue either really. They reset the pcm and the fans started functioning. Luckily, I haven’t had an issue again. So as a last resort, reset the pcm by disconnecting the battery for a few minutes. Good luck.
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No low coolant etc there is no leaks fans also work both of them so I don’t know what the problem can be .
I checked exact degree of the coolant it looks like it goes to like 220 and stays there for a while and goes back down I think it is just how this car works I read 240 and higher is overheating so I assume 220 is still ok because it goes around 195-220 degrees but doesn’t go higher. I assume fans starts to work when it reaches over 220 degrees goes I was waiting for my car to reach the top highest idle temp it went around 65% again but it went back down to 50% quickly after.
Hope it helps to people out there with the same issue maybe it is just how the car works.
On every vehicle I’ve owned the coolant stays at a pretty constant temperature once the engine is warmed up. This presumes there’s no unusual driving situation, like going up a steep hill pulling a trailer on the hottest day of the year. There is a little upward deflection of the dash gauge on my Corolla if the engine is in a long idle, but not much, certainly not much over half-scale, and that temperature rise is halted immediately when the radiator fan turns on. When my vehicles have failed to hold a steady coolant temperature it is usually one of these
- faulty thermostat
- cooling system not holding its designed pressure
Yes, I believe the electric fans don’t come on until 220 degrees (or the AC is turned on). After the engine temp drops from 220 (to what exact temp, I don’t know), the fans will cut off again.
It sounds like there may be a problem with your thermostat (yes, I know it was replaced a year ago). remove your thermostat and place it in a pan of water. you can use a kitchen thermometer, but in your case ,as long as it fully opens before the water boils, it is ok.