Greetings from Croatia 626 GE 2.5 V6

[JokeCro]

Guys, question, it happens that the engine cooling fans turn on late. So, the temperature needle moves quite far from the middle, and then the fans turn on and the needle slowly returns to the middle.
This was not the case before!
Before, the needle was stationary in the middle, and if it moved a little forward, the fans would turn on.

Is it possible that it is the radiator fan thermal switch sensor?





I tried to check if both fans were working. I started the car (cold engine) and turned on the air conditioning and both fans started.

[Kampfkuchen]

In my opinion the ECU switches the radiator fan on, dependent on the ECU thermal sensor. I'm not 100% sure anymore, but I think there are 2 thermistors and one switch for whatever. One thermistor for ECU (gasoline correction factor and fans), one for the needle.

I think what happend here is, that the NTC for the ECU has driftet a bit or the analog input has some issue. I would try to change the NTC or at least measure the resistance at cold and hot motor.

[JokeCro]

I also noticed a slight leak of coolant under this cap.



Does that cap hold the pressure at 1.1? Since the expansion tank on the radiator says 0.9?

[JokeCro]

In my opinion the ECU switches the radiator fan on, dependent on the ECU thermal sensor. I'm not 100% sure anymore, but I think there are 2 thermistors and one switch for whatever. One thermistor for ECU (gasoline correction factor and fans), one for the needle.

I think what happend here is, that the NTC for the ECU has driftet a bit or the analog input has some issue. I would try to change the NTC or at least measure the resistance at cold and hot motor.

I think you should buy this new green sensor.

[JokeCro]

A little update, I had come from the city and left the car alone to run for a while. When the temperature gauge started to climb above half to a certain level when the fans turned on, not both were working, but only one.

[commander_keen]

The second fan is for the air conditioning condenser.

The motor cooling fan in the V6 has two fan speeds (low-speed and high-speed),
while the 4-cylinder cooling fan has only one speed.

[JokeCro]

The second fan is for the air conditioning condenser.

The motor cooling fan in the V6 has two fan speeds (low-speed and high-speed),
while the 4-cylinder cooling fan has only one speed.

Now when the radiator fan turns on (when the temperature gauge goes further well past halfway), there's a really loud noise, as if the fan is running at 100% speed.

This is where the fan turns on.
And then he returns to the boat.
The fan doesn't always turn on when the needle reaches the same level, sometimes a little earlier, sometimes like in the picture

[JokeCro]

Relay no. 1

[Kampfkuchen]

Okay I think I checked what's wrong:

Your low-speed is not working and when the ECU turns on the high-speed, you have a higher temperature as normal.

I also think that both fans should ran at low speed, when the temperature reaches the threshold. But not 100% sure.

You can try to go into diagnostic mode by bridging TEN to GND and then open the throttle (without engine running). The fan has to start if you open the throttle.

But I think you have a problem with your relay no 1, if it has a crack, maybe it's corrosion. You can open it and have a look. Or open it, plug it in and turn on manually. If the fan starts, this should be your problem.