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2004 Boxster (986) 2.7L Front fans running loud

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I hope you can help.

I have a 2004 (986) standard 2.7L Boxster.

The last couple of days There is a loud noise when the air conditioning is running. Seems way more loud than usual - especially at idle (probably because of less engine/road noise).

I think the issue is that the fan behind the front bumber is coming on when I turn the air con on. The fan seems to be on anytime the a/c is on. Is this normal. It just seems very loud and I dont think it was there a few days ago.

I looked at the radiator through the vents in the bumper and there seems to be a slight layer of dust on the radiator - though not too much. Could this be the issue?

The problem can be heard even when I strat the car from cold.

I have read that there are two fan speeds. When the A/C is turned on - what speed should they run at - how can I tell?

How do I clean the dust from the radiator (preferably without having to remove the bumper)?



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When A/C is on low speed fans turn on. Both sides. In certain conditions, the high speed fans will kick on.

If you want to see what the high speeds are like you can activate them in software such as Durametric. Or pull the low speed fan relays and IIRC the high speeds should kick on and off every few seconds or minutes. Then replace the relays. With the AC off the fans should not run on a cold car.

To clean the radiators it's best to remove the front bumper, but in leiu of that a garden hose, a long vacuum hose attachment, followed by a good drive to get them up to temp to dry them off will work. Don't touch the fins with anything or you'll bend them.

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Thanks logray

So the fans do turn off and on with the A/C.

How audible should the fans be on Low Speed.

If they are running at High speed when the AC turned on, what might be the problem?


Explained before (996 and 986 are the same) here:


The number one cause of fans running too much is debris stuck to the front of the radiators and/or AC condensers.


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Thanks Loran.

The post says:

Electric fan, speed 1

(Ground to DME control unit, terminal 35)

Coolant temperature higher than 96.75° C or air conditioning switched on.

Electric fan, speed 2

(Ground to DME control unit, terminal 36)

Coolant temperature> 102° C or air-conditioning fluid pressure switch closed (coolant pressure> 16 bar).

Is there any easy to tell if it is running at speed 1 or 2.

I am almost positive that there us much more noise than a week ago which would suggest that are running at speed 2 (high) - even when initial startup when stone cold. The above suggests they should come on at low speed. So any indication on how to tell which speed they are running at would greatly help.

I will check and clean the fans also - but I dont think they are too bad and i could understand this causing a problem as things warm up due to reducing efficiency of the cooling. My issue is right from startup.



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