Air con cause radiator fan to go full speed

[Slow_poke_driver]

For as far as I can remember...probably since the first day I collected car almost 3 years ago...

My radiator fan will go full blast for 5-10s whenever I restart the car while the engine is hot. For instance if I park my car, go kopitiam buy rice, then come back to restart the car, the radiator will go really loud for 5-10s. After the initial few seconds of fan blast, it will go quiet.

Occasionally, the fan continues on for 20-30s, but generally it stops once I start driving at speed.

It does not do it when the car is started cold.

Two workshops that I went to for general servicing also commented on my loud radiator fan.

I have traced it to air conditioning, where leaving the a/c off seems to eliminates this loud radiator fan issue.

My air con is blowing cold and strong. What can be wrong with the system?

 

[Slow_poke_driver]

Re: Air con cause radiator fan to go full speed

Exactly like what this guy described.

Loud fan noise - Bimmerfest - BMW Forums

Coincidentally, mine is also a 12 520i.

I don't think it has anything to do with water pump coz I don't think a weak water pump can survive for 30+k km.

 

[nob]

Re: Air con cause radiator fan to go full speed

Does the oil temperature go above 90 degrees?

I had the same problem with the fan and at the end of the day it was the thermostat that was faulty.

 

[Viper Warrior]

Re: Air con cause radiator fan to go full speed

Its normal ... same for mine especially for a hot day.

 

[WhiteE90]

Re: Air con cause radiator fan to go full speed

Does the oil temperature go above 90 degrees?

I had the same problem with the fan and at the end of the day it was the thermostat that was faulty.

similar problem I had and still unresolved,

changed the thermostat to no avail.

one WS suggested that my radiator could be nearing its end of life and to replace it. I am still deciding though

 

[Jason8822]

Re: Air con cause radiator fan to go full speed

I have this symptom too.
Maybe car doing system test upon start up.

 

[Slow_poke_driver]

Re: Air con cause radiator fan to go full speed

Ok...seems like it is a common occurance and probably not an issue.

My oil temp is about 90-95c on normal driving. High-way about 100-110c. I think quite normal.

 

[douggie]

Re: Air con cause radiator fan to go full speed

Yes. It's normal. Residual heat can really build up after you shutdown a warmed up engine (no more oil and coolant flow).

 

[wt_know]

Re: Air con cause radiator fan to go full speed

i'm facing this problem.
how many fan are there? is there a fan for radiator and fan for aircon or something like that?
the fan always go full speed ... i'm not sure it's full speed or not but the sound is sibei loud

many commented that this is normal but i'm not entirely convince because this symptom only appear recently
previously the engine sound was ok ... not hybrid type of quiet but certainly not as loud as now
i know that it's not engine sound but fan or something else

no error code, temp is normal between 70-120c
pick up is not affected ... drive still swee swee

also read up that possibility is fan problem or the termostat sensor failing that affected the fan to run on full speed?

going for servicing soon ... what should i tell the SE to double check and verify ... better get a replacement while under warranty

stop at traffic light with D mode ... sound bearable ....
park at P mode ... walao ... sound sibei loud

 

[Slow_poke_driver]

Re: Air con cause radiator fan to go full speed

Your fan will stop after a few seconds?

BTW, think only one fan. Bad design for a family car. Two slower fan is really better than one.

 

[wt_know]

Air con cause radiator fan to go full speed

no, the fan did not stop nor slowdown
not sure is the fan or what else that is generating continous sound like heavy machinery in operation

 

[kennypmf]

Re: Air con cause radiator fan to go full speed

no, the fan did not stop nor slowdown
not sure is the fan or what else that is generating continous sound like heavy machinery in operation

Same issue encountered too for a 2012 F10. Previously PML changed a solenoid or thermostat before and the high speed fan went back to normal and will go off when the engine is very hot but after about 6-7months now the high speed fan is blasting all the way.

 

[wt_know]

Re: Air con cause radiator fan to go full speed

did a diagnostic at codewerx and confirm the "map thermostat" up lorry liao ... going to claim warranty

Same issue encountered too for a 2012 F10. Previously PML changed a solenoid or thermostat before and the high speed fan went back to normal and will go off when the engine is very hot but after about 6-7months now the high speed fan is blasting all the way.

 

[Jason8822]

Re: Air con cause radiator fan to go full speed

did a diagnostic at codewerx and confirm the "map thermostat" up lorry liao ... going to claim warranty

Its a sign .... pointing at something
G series 5er round the corner ...... you know what i mean

 

[wt_know]

Re: Air con cause radiator fan to go full speed

itchy for coupe la ... 428i

Its a sign .... pointing at something
G series 5er round the corner ...... you know what i mean

 

[Slow_poke_driver]

Re: Air con cause radiator fan to go full speed

For mine, the fan will stop within 30s max.

Codewerx tried to help me scan for fault, but only found some minor insignificant air con error warning.