Radiator Fan Problem

[ATLaccord]

Hi all,

I believe there's something wrong with my radiator fan/Temp sensor/Fan timing unit.

My car overheated (blown radiator) in the summer of last year. Before that, my radiator fan came on frequently and was also running for a while once I parked the car.

The radiator and thermostat were replaced by a shop at the time and since then I've learned to do a lot of repairs by myself (Thanks mainly to a lot of help from this forum).

I've never heard the fan come on with the car parked since the overheating. So I'm thinking something's wrong. Here's what I've tried so far:

- When I jump the thermo switch plug (thermostat housing) the radiator fan comes on

- I changed the relay with the power window one, and it is OK

- I changed the thermo switch in thermostat housing to no avail.

- When I idle the car for 15 mins, the radiator fan comes on briefly twice, but it does not stay on

- I'm pretty sure there's no air in the system, I've bled it thoroughly

- The temp gauge does not ever seem to go beyond mid point (except once this summer, when it overheated because of a blown hose)

My feeling is that the rad. fan should be running after shutdown and doesn't. I'm also not sure about the temp gauge. Could it be that the sending unit it malfunctioning? How do you test that? Could it be that the Fan timing unit is not working correctly and that's why the fan is not running with the engine shut off?

Thanks for your ideas

[07BLKNINJA]

first is your car overheating? (from what i read no) , to test the fans, warm the engine up by holding the rpms at 2k or drive around till its warmed up, then park and let it idle, with out the blower fan on or the A/C. after a few min. the fans should kick on and control the temp of the car. if you gauge goes up, and up with no fan function turn it off and let it cool. this way u "know" the fans are not operating as they should. then u can look into things such as air pocket in cooling system, or fan control not working. or something to go off of but unless u know it isnt operating correctly your chasing your tail.

i know on mine the fans usually are not on when i shut the car down. but about 5-10 min after they will come on for about 2 mins and then shut off. so to me urs sounds like its working like it should

[Potatoswatter]

Maybe it's on but you don't hear it? Perhaps the garage put oil on it?

One of my fans used to be really noisy, and recently it started running quietly so I can't hear it from inside the car. So maybe close the fan switch to make it run, and check that you hear it inside.

[IridiumCore]

Check you fuse in the engine compartment. Several of us are actually having this issue. With me my fans just cut out after state inspection. I'm not going back to any pepboys.
I put in the right place and they are both working. This is after replacing the thermostat and ECT sensor. My temp gauge was jump all they way to hot.

In your case I hope its this simple but before you do anything major check the fuses. You may need to replace the temp sending unit also.

[ATLaccord]

I've confirmed now the fans are running after some Atlanta rush hour traffic, if I let the car idle. Both fans came on, but they don't kept running, it was more like they run for 1 min, shut down then they came back on, run for a min, etc.

Is this normal, or should they run continiously?

Immediately after, I shut the car down and waited for 10 mins, but the fan did not come on.

Should it have come on, given that the engine was clearly hot?

Also, I'm still wondering if my temp gauge is correct. It normally never reaches even 50% of the scale:


Does this seem normal?

[07BLKNINJA]

yes thats normal. they only come on to regulate the temp when your not moving and air is not moving across the rad. and ur gauge looks perfectly normal.