Loud fan on cold startup

[Spooik]

Hi All,

Bought my E89 2012 2.0L last year and have had trouble free motoring so far (touch wood). But recently I have had an issue. 1 out of 3 times when I start the car,
(Cold start) a loud fan from the engine will kick in and generally remain o.

I thought it might have been the coolant temp sensor so changed that but to no avail. Car is bringing up no fault codes, no leaks, water pump is working, no loss of coolant and car drives fine with no issues. So thought I would ask if anyone has any experience with the same issue? Possible water pump due to fail? Thermostat?

Thanks.

 

[Anonymous]

I had that same issue after I changed the coolant and then it went away..

Have you tried the coolant purge option to see if bleeding it may persuade the DME that all is ok?

 

[Smartbear]

The n20 cars are noisy on initial cold start due to some emission shenanigans but it goes away after a minute or so, are you sure it’s not that?
Rob

 

[Spooik]

I had that same issue after I changed the coolant and then it went away..

Have you tried the coolant purge option to see if bleeding it may persuade the DME that all is ok?

I did bleed the coolant system after changing the temp sensor but I was thinking about doing a complete flush of the system.

The n20 cars are noisy on initial cold start due to some emission shenanigans but it goes away after a minute or so, are you sure it’s not that?
Rob

I think I know what you are talking about and mine does the same, but this is the actual fan kicking on after a few seconds of startup. I am certain it is either something failing or a dodgy sensor. I did one time drive with the fan noise on for 20 miles but it was still on. It seems to only turn off when i put the heater on so I assume there must be some issue with the cooling system.

 

[Anonymous]

When you said ‘bleed’ did you do the 12 minute auto purge stuff?

 

[Spooik]

When you said ‘bleed’ did you do the 12 minute auto purge stuff?

Yep that is what I did.

 

[Anonymous]

Well there are two thermostats that can trigger the fan..you replaced one..did you do a test on the bad one?

I say that as I bought a brand new Vaico inlet pressure sensor only to find it was duff..

 

[flybobbie]

Is the aircon on, or on auto.

 

[Smartbear]

How many miles has your zed covered? My 3.0si did the same thing with the fan from cold start which was an early warning of impending water pump disaster
Rob

 

[Spooik]

Well there are two thermostats that can trigger the fan..you replaced one..did you do a test on the bad one?

I say that as I bought a brand new Vaico inlet pressure sensor only to find it was duff..

I only replaced the coolant temperature sensor.

Is the aircon on, or on auto.

Nope aircon is off.

How many miles has your zed covered? My 3.0si did the same thing with the fan from cold start which was an early warning of impending water pump disaster
Rob

Just done over 70,000 miles now. I did suspect it might need a new water pump but wanted to eliminate all other possibilities first.

 

[Spooik]

Hi All,

Thought I would post a follow up (just in case anyone is having the same issue). So over time, would get the overheating signal on my dashboard come up (yellow warning only).

Took it to a specialist and they said water pump was dying. Changed the water pump and thermostat but the fan was still blowing loudly while driving (and no longer at start up).

Changed the coolant temp sensor and all seems to be well and in order now.

 

[matsmith749]

Thanks for coming back & updating.

For anyone else with similar type symptoms, this could be easily checked with a scan tool - you can verify that the temp sensor is working in 2 minutes flat & save guesses.

In this case, water pump & thermostat **could possibly** have been part of the problem - but the sensor was actually the thing that resolved it.

Would have been hundreds of pounds better off by doing the sensor only & assessing from there IMHO.

 

[Spooik]

Hi there,

I did indeed first just change out the coolant temp sensor before proceeding with changing the water pump and thermo. Also had the car scanned when initially the fan would kick on but no codes and no warning lights appeared.

It was only after when the overheating warning came on that the codes popped up and the pump was changed.

The issue I had after was the fan (and at times overheating warning) would still come back (not on a cold start unlike before).

I had read someone (in another forum for a different BMW) had the same issue as me after changing their pump and suggested to change their sensor too which has worked for me.