Cooling fan overrun?

[andyfitzgerald]

Hi - not sure if this is an issue or not.  I have a Mk5 2008 Gti DSG and every time I stop and switch off engine the big cooling fan runs for a few seconds .. not much more at all.  Just wondering if this was normal? No excess temperature at all, nothing too hot etc?

[Madone]

Sounds odd to do it every time, my car does it rarely, def not every time. Is it running all the time when the engine is actual running, and you just notice it when you turn the engine off ?

[andyfitzgerald]

Yeah. Just runs for a few seconds .. found it abit odd. Not long been serviced and MOT'd with no issues.

[andyfitzgerald]

It's appears to be running when the engine is on and then when I switch off it is slowing down to a stop and that's what I can hear.

[Madone]

It could be the radiator temp sensor, it's located below the thermostat. If the ecu can't work out the radiator temp it will run the fan all the time to be safe. If you can get vcds you can read both engine temp sensors, block and rad.

[Northy1985]

Mine is doing the same I noticed today on dash temp is fine (in the middle) but fan constantly runs

[andyfitzgerald]

The fan definitely runs all the time. When I shut the car down the fan shuts down too and it winding down is what I can hear. It's literally lasts for a few seconds only then stops. No excessive temperatures at all. Strange!!

[Northy1985]

Mine is just the same

[Madone]

The fan definitely runs all the time. When I shut the car down the fan shuts down too and it winding down is what I can hear. It's literally lasts for a few seconds only then stops. No excessive temperatures at all. Strange!!

You need to check the rad temp sensor, the temps will fine in the engine, the rad will just be much cooler and the thermostat  open less to keep the engine at 90. Your fan will wear ultimately if it's on all the time too. Also worth checking the actual engine temp with vcds as well as the rad temp, the gauge will read 90 even when the main stat has failed and the car actually running at 75 !. Loads of threads on here about the main stat. It's common to fail as cars get older.

[OEM+ DUB]

Hi there

Couple of checks to help get to the bottom of why the fan (and which...) are running constantly.

Firstly, does the fan run constantly when the aircon is on?
If it does, is it just the large fan running?
If the small one isn't running (with the engine cold and turned off!) can you spin the blades by hand?

If the answer is yes to the first two questions you are looking at a probable issue with the small fan.  The last question will indicate if it is seized or (as was the case with mine) one of the brushes on the motor has stuck in the retracted position.  If it points to being seized its going to need swapping out.  If it's likely a stuck brush then with care you can open and free off.

Hope this helps.

[andyfitzgerald]

Update - took car to the local garage who diagnosed the temperature sensor was not working correctly causing the fan to come in virtually all of the time.  Being replaced as I type.

[Madone]

Update - took car to the local garage who diagnosed the temperature sensor was not working correctly causing the fan to come in virtually all of the time.  Being replaced as I type.