I have a problem with my evo7....the engine fan isn't turning on when the engine reaches its normal operating temp....thus resulting in above normal temps... But when i turn on the Aircon both fans are working (good and strong air flow) and temp stays normal. So that eliminates a defective engine fan.

I've chaeck connectors and all is intact. Check water level....its good. replaced the thermosat with a new one.

Im now thinking of replacing the thermo sensor located on the elbow...i think its already defective....i think its the one sending signal to the ECU to turn on the aux fans...right?

Do i have to check for anything else......?

Btw, im running an Apexi FC commander on the car....is there a temp setting that controls the fans that i might need to set?

Sorry for the long post

Anyway inputs will help....

thanks guys

 

Check your grounds. Also, check to make sure the fan switch is working properly.

 

I had a similar problem with my 7. The culprit = Engine cooling sensor module problem. There is a recall in this item on the Evo 8 models.

This sensor is located behind the engine cooling fan.

 

fan switch relay like nrcooled mentioned ..

square black box behind the fan near the tranny side..

 

Sir..

I just observed the car awhile ago....the engine fan is working but it only at a very LOW LOW speed.--->note Aircon is not turned on.

Is fan swith relay (like gunzo and nrcooled is reffering) and Engine cooling sensor (gunzo metioned) the same....???

So if the sensor is defective....the fan will NOT turn on automatically.....and will jst turn on when Aircon is activated


Onie

 

bump...

 

just make sure not to drive it until you get it sorted out...
overheating can be your worst enemy.


and if the fan is working but at a very low speed..then there could be something wrong with the fan itself and not the sensor.

hook up the fan directly to a power source and see if it is operating how it should. then you would know if it's the fan or the module

 

I removed the fan and tested directly to a 12V source....it spins fast and airflow is strong.

Im gonna replace module located at the fan...and post the results later.

Onie

 

Well it looks like you found the culprit. Good luck with everything. I dont think you have to worry about it overheating now.

 

Changed the module on the fan....but its still the same.

here's what i observed....when i turned on the engine and let it idle for a few minutes. After awhile... Engine fan turns on (low speed) and turns off automatically. after a few minutes fan turns on again. But this time temp reading is at 3/4 already. After awhile temp gauge is normal again...in short i get erractic/ irregular reading on the temp gauge. One more thing i observed when i turn-on the aircon from normal reading the temp gauge immediately shots up to full high then slowly goes down.

Could it be it be a defective temp sending unit?

One more thing i observed...when temp gauge is above normal....temp on the radiator seems normal not even a spill out of the radiator cap. So no sign of overheat.

Sorry again for the long post.

 

is the temperature going up while the car is in motion?
or just at a standstill?


check the overflow bottle......is the water level in it higher than usual?
also..check for any sign of oil in the radiator....

 

^ why?

 

Because those are signs of a blown headgasket.

 

how come the radiator res is higher than normal?

 

here's a few other check areas then..

if you can get a water temp gauge for comparison.. that checks out your temp sending unit

lastly.. it could be a defective thermostat not opening when it needs to..