Radiator fan only turns on with AC

[_-Night-Shade-_]

Hey guys, just recently I noticed that my cooling fan (the bigger radiator fan) is never on, even when I reach optimum operating temperature. The smaller fan on the left is never on also but that's the AC fan that goes on only when the AC is on. But here's the interesting part: when I turn on my AC BOTH fans go on! What's going on here?

[Mad Cow]

If it's at operating temp. the the air from movement could just be enough to keep it cool. What if you let it idle without moving for a while?

[_-Night-Shade-_]

Lol how do you think I can see if it's moving or not? Obviously the car was idling when I checked

[Evo_Spec]

wut? i thought you were hardcore and checked it when you had the hood popped while driving 100 down the highway

in all seriousness, i think he ment leaving it idle for a little while (like 10 min or 20) and see if the fan turned on

[_-Night-Shade-_]

Well I drove around for a while with sound off and everything so I could hear if it turns on cause it's loud enough to hear even from inside, and still nothing. I don't see the point of letting it idle for 20 mins unless you're suggesting that every mx3 is like this. I've heard for some it turns on the moment they start the car

[Mad Cow]

With alot of cars, just movement pushes enough air through to keep it cool. Just let it idle for 10 mins of so and see if they turn on.

[_-Night-Shade-_]

Okay I guess it's worth a shot, I'll give it a try today and let you know how it goes.

[_-Night-Shade-_]

Hey guys sorry for taking so long to get back on this. So after topping off my coolant (I realized I was low) and getting a new rad cap just in case, I decided to do the idle test. After 5 mins with the hood up, and then 3 mins with the hood down, I was about to give up when the fan kicked in on the 8th minute of idling Phew, I was starting to think that I had a bad coolant sensor or that the relay wiring had been changed before I got this car. I'm surprised it takes it so long to start heating up, this is the first time I've seen the cooling fan turn on by itself, though I've never had overheating issues, it was always at normal temperature even with low coolant and the fan not operating (needle is a hair above the midway point, but I guess that's where the normal is on my car). Thanks for all the help guys!

[Mad Cow]

Yea I've noticed these motors take a while to heat up, my ZE reaches the middle on the gauge after at least 10 minutes.

[Whisper]

I've heard for some it turns on the moment they start the car

Yeah, it does for some, but it's usually a result of faulty or missing temp sensor or wrong ECU, mostly when people swap in ZEs. That's not normal, though. So technically if your temp sensor was bad, your fan would run all the time.

[MX-3-Tom]

Hi guys, I just pick up the topi.
I have a KLZE too.
My temperature gauge is constant a bit under the middle.
But I also didn't hear the radiator fan yet.
When I switch on the A/C, both fans start working.

@NightShade:
It took 8 minutes with warm engine to start the radiator fan?
I like to do the idle test too.
Do I have to warm up the engine before starting the test?
I want to control the temperature be using a thermometer. What should be the maximum temperature?

[_-Night-Shade-_]

Yeah I did it on a warm engine, so it took 8 minutes for it to get that much warmer that the rad fan had to kick in.

[Nd4SpdSe]

Ya, I don't think my rad fan ever turned on while moving. Basically it's only there to move air when your not moving, cause when you're not moving, there's nothing to push air across a fan

BTW; "a watched pot never boils"

[MX-3-Tom]

Hi, thanks for answering.

Tomorrow, I'll check the GND+TEN-Bridge:
- ignition on, gas-pedal not pushed down --> radiator fan kick in for a short time
- ignition on, gas-pedal pushed down a bit --> both fans kick in

Is that right?


And then I'll heat it up and then I'll idle it for a while.
I'll control the temperature with a thermometer which I put into the hole, where you can fill the system (betwenn the heads).

[Mad Cow]

I'm not sure about the AC fan because I don't have AC, but the rad fan should only kick in if you press the gas pedal in test mode.