Cooling fan continues to run while engine is off

Hi all,

I'm new to the forum so please be gentle
My Mrs got a low mileage 2015 C3 handed down from her dad last year as he is no longer able to drive. The car ran relatively well until around last October when the internal blower (heating and cooling) stopped working. We took it into the dealer who said the whole unit needed to be replaced, so we decided to live with it as we didn't use the car that often at the time. Then a few months ago the engine cooling fan started coming on at full power almost immediately after start, and continues intermittently while driving, but will also continue running for quite a long time after the engine is turned off.

The System did not show any warnings on the dashboard or on the in car diagnostic system (I will run a diagnostic when I can find my OBD reader) until last week when the service light came on in the dashboard.

I did a few google searches and the coolant level sensor does seem to come up as a common issue, but unlike a lot of other models, our C3 does not seem to have the sensor next to the reservoir tank, so am unable to do a quick replacement and test it.
Is there a chance that the two (blower and engine fan) issues are related? Seems unlikely to me.
Anyone else have this issue? Any ideas what I should be looking for or checking next?

Aside from the fans and a squeeking/griding sound from the brakes, the car seems to run ok.

whatuser wrote: ↑Wed Oct 06, 2021 9:20 am Hi all,

I'm new to the forum so please be gentle
My Mrs got a low mileage 2015 C3 handed down from her dad last year as he is no longer able to drive.

Then a few months ago the engine cooling fan started coming on at full power almost immediately after start, and continues intermittently while driving, but will also continue running for quite a long time after the engine is turned off.

The System did not show any warnings on the dashboard or on the in car diagnostic system (I will run a diagnostic when I can find my OBD reader) until last week when the service light came on in the dashboard.

I did a few google searches and the coolant level sensor does seem to come up as a common issue, but unlike a lot of other models, our C3 does not seem to have the sensor next to the reservoir tank, so am unable to do a quick replacement and test it.
Is there a chance that the two (blower and engine fan) issues are related? Seems unlikely to me.
Anyone else have this issue? Any ideas what I should be looking for or checking next?

Aside from the fans and a squeeking/griding sound from the brakes, the car seems to run ok.

Hello

Welcome to the forum

Your faults are not connected.

The heater blower will need it's own topic if you want help with that common problem on the Citroen C3.


The coolant level may be low, what is your coolant level at?

Hi C3Car,

Thanks for the reply and advice on the blower thread.

Coolant levels is at max. I've checked it a few times, it isn't dropping and don't see any leaks or puddles under the car.

I suppose it might be worth flushing the system as a precaution, so might try that over the weekend.

Thanks again.

whatuser wrote: ↑Wed Oct 06, 2021 9:52 am Coolant levels is at max. I've checked it a few times, it isn't dropping and don't see any leaks or puddles under the car.

I suppose it might be worth flushing the system as a precaution, so might try that over the weekend.

Hi

While the system is drained for flushing (if the colour is good, you can re-use it, if the colour is off, like brown, then replace it), you can change the sensors for temperature on the engine. It may be faulty and giving the ECU a false reading that means the fan runs more than it should.

Sorry but I'm not that familiar with the newer model of C3 but I believe that they haven't changed the basic engineering principals behind the design.

whatuser wrote: ↑Wed Oct 06, 2021 9:20 am The car ran relatively well until around last October when the internal blower (heating and cooling) stopped working. We took it into the dealer who said the whole unit needed to be replaced,

If every thing else appears to be working (the buttons and switches on the control panel light up ETC) check the appropriate fuse in the engine bay. See; interior blower fan in your owners manual. The cabin air fan circuit is very problematic. It draws a lot of current and tends to burn out a number of things in the circuit. The usual suspects are the fan speed controller, it may be electronic or resistors. The electrical connectors, they tend to melt. The fuse in the engine bay can melt also.

whatuser wrote: ↑Wed Oct 06, 2021 9:20 am Then a few months ago the engine cooling fan started coming on at full power almost immediately after start, and continues intermittently while driving, but will also continue running for quite a long time after the engine is turned off.

Does the fan sometime come on with the car sitting and no one in it? I suspect the thermo fan power relay. Not sure on that one. The power relay tends to give trouble while the engine is off not on. The usual suspect with your symptoms is the engine coolant temp sensor. However the engine temperature indication on the dash tends to go crazy at the same time. But that doesn't seem to be the case here. Pull the three pin connector on the thermo fan cowling apart and look for corrosion or bad connection. Pull the electrical connectors on the engine ECU off and look for corrosion on the pins of the engine ECU.

whatuser wrote: ↑Wed Oct 06, 2021 9:20 am I did a few google searches and the coolant level sensor does seem to come up as a common issue, but unlike a lot of other models, our C3 does not seem to have the sensor next to the reservoir tank, so am unable to do a quick replacement and test it.

As far as the C3 is concerned, it only seems to be the diesels that have the coolant level sensor.

My recommendation would be to take your car to an auto electrician. They should find the problems pretty quickly. For you to DIY it, you would at least, need a multi meter and the willingness to go fishing in the engine bay and behind the dash. The dealers are hopeless. They are either incompetent or greedy . Sorry.

whatuser wrote: ↑Wed Oct 06, 2021 9:20 am Aside from the fans and a squeeking/griding sound from the brakes, the car seems to run ok.

The squeaking/grinding sound from the brakes will be either worn or cheap brake pads. Look at the front discs. If they look like an old vinyl record it might be time for the brake to be looked at. If there is plenty of meat on the brake pads and the disc is OK it's just cheap pads. Live with it or replace them.