Air con fan noise

Arryhall · 23rd March 2017, 11:43

Hello! I know I'm probably getting on everyones parts now, but I have another question to which I can't find an answer. Probably because I don't know how to phrase it nor what things are called!

Right. Here we go.

When I turn on the air con, the fan starts. I don't know if this is the main fan, a dedicated air con fan or what. But it seems rather noisy. When I turn the engine off, there is a short, few seconds overrun with the fan, which, when late at night, makes the noise of it more noticeable. I don't know if there are several fans or just the one, but is a noisy fan normal, or is it on its' way out, or has it already gone out, got it's coat and is hailing a taxi back home? It's being looked at tomorrow for the turbo lag / NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD- thing, and I would like to know if I ought to get this looked at under warranty or if it's a nothing job, or if it's a major job. If the car has major issues, I can take the thing back as it is still covered under the garage warranty if it is going to die soon. But I've had the thing nearly a month now and it's getting close to no return!

Help!

suzublu · 23rd March 2017, 12:19

Normal

Heddy · 23rd March 2017, 12:39

Not usually detectable whilst travelling. If it's loose or on some fans the circlip has dropped orf then there would be a heck of a clatter.

Arryhall · 23rd March 2017, 12:49

Cheers!

It's not a rattle, just a loud grumbly fan, only really noticeable as a background grumble, but when stationary, with the ignition on but engine off for example, it's a growly rumbling low fan noise, but certainly no rattles or coughs or metal screeching or anything.
I shall stop worrying about it.

Dallas · 23rd March 2017, 14:57

Hearing the large noisy 18" radiator fan running is music to ones ears, you should start to worry when you dont hear the fan running.

If your fan is constantly running when using aircon and stops once aircon is switched off, this is normal.

Does your fan run at any other time when aircon is not being used, especially in cold cool weather?

murphyv310 · 23rd March 2017, 15:02

As Dallas says the fan runs continuously with the A/C on, if it pulses on and off then the slow speed is inoperative.

T-Cut · 23rd March 2017, 15:24

The later 1.8 engines have a 2-speed radiator fan with the slower speed provided by the infamous resistor. The two speeds are described as noisy and noisier. The aircon system requires the slower speed running continuously. The engine will also trip this on if it reaches 104C.

The faster speed is less used and is primarily for cooling an overheated engine, often after shut-down (heat soak). It will also be tripped on for emergency cooling in the event of the slow speed being inoperable. Since your slow speed seems to be operational, check if it has the 'gold' resistor upgrade in place. Look through the front grill and through the fan blades. You'll see a resistor in the 2 o'clock position on the fan guard. The original, underpowered one is aluminium in colour. The upgrade type usually has a gold anodised finish.

It's useful to be able to recognise the two fan speeds (noisy and noisier). The Demist Test will/should trip on the slow speed at will.

The high speed can be tripped by temporarily disconnecting the engine coolant temperature sensor and starting it up.

TC

Arryhall · 23rd March 2017, 21:09

So far I haven't driven the car for long enough distances to trigger the higher speed fan, just checked and double checked the operation and yes, air con makes the fan come on. Turn air con off and fan stops. Plus it's been COLD!

I'll check the resistor when I get the car back from the mechanic looking at the 3500rpm blip, having the rear seat fitted now it's dry underneath, loose handbrake and a couple of other bits. Also the guy was looking at the noisy fan!

T-Cut · 23rd March 2017, 21:31

Quote:

Originally Posted by Arryhall

Also the guy was looking at the noisy fan!

Maybe the motor bearings or a slack blades unit.

TC

23rd March 2017, 11:43	#1
Arryhall Loves to post Rover 75 Join Date: Mar 2017 Location: Biddulph Posts: 486 Thanks: 101 Thanked 145 Times in 90 Posts	Air con fan noise Hello! I know I'm probably getting on everyones parts now, but I have another question to which I can't find an answer. Probably because I don't know how to phrase it nor what things are called! Right. Here we go. When I turn on the air con, the fan starts. I don't know if this is the main fan, a dedicated air con fan or what. But it seems rather noisy. When I turn the engine off, there is a short, few seconds overrun with the fan, which, when late at night, makes the noise of it more noticeable. I don't know if there are several fans or just the one, but is a noisy fan normal, or is it on its' way out, or has it already gone out, got it's coat and is hailing a taxi back home? It's being looked at tomorrow for the turbo lag / NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD- thing, and I would like to know if I ought to get this looked at under warranty or if it's a nothing job, or if it's a major job. If the car has major issues, I can take the thing back as it is still covered under the garage warranty if it is going to die soon. But I've had the thing nearly a month now and it's getting close to no return! Help!

23rd March 2017, 15:02	#6
murphyv310 This is my second home Hyundai i10 998cc Join Date: Mar 2012 Location: Kilmarnock Posts: 6,602 Thanks: 2,088 Thanked 2,298 Times in 1,349 Posts	As Dallas says the fan runs continuously with the A/C on, if it pulses on and off then the slow speed is inoperative. __________________ Cheers from Trevor MM0KJJ

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23rd March 2017, 12:19	#2
suzublu This is my second home rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009 Location: Seaton Carew Posts: 26,911 Thanks: 65 Thanked 7,142 Times in 4,642 Posts	Normal

23rd March 2017, 12:39	#3
Heddy This is my second home None Join Date: Feb 2013 Location: None Posts: 5,556 Thanks: 465 Thanked 1,161 Times in 924 Posts	Not usually detectable whilst travelling. If it's loose or on some fans the circlip has dropped orf then there would be a heck of a clatter.

23rd March 2017, 12:49	#4
Arryhall Loves to post Rover 75 Join Date: Mar 2017 Location: Biddulph Posts: 486 Thanks: 101 Thanked 145 Times in 90 Posts	Cheers! It's not a rattle, just a loud grumbly fan, only really noticeable as a background grumble, but when stationary, with the ignition on but engine off for example, it's a growly rumbling low fan noise, but certainly no rattles or coughs or metal screeching or anything. I shall stop worrying about it.

23rd March 2017, 14:57	#5
Dallas This is my second home 1979 Capri 1.6L, 1982 Capri 1.6L, 2016 Dacia Stepway Join Date: Jun 2009 Location: Dorset Posts: 8,595 Thanks: 3,496 Thanked 3,397 Times in 2,218 Posts	Hearing the large noisy 18" radiator fan running is music to ones ears, you should start to worry when you dont hear the fan running. If your fan is constantly running when using aircon and stops once aircon is switched off, this is normal. Does your fan run at any other time when aircon is not being used, especially in cold cool weather?

23rd March 2017, 15:24	#7
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,751 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	The later 1.8 engines have a 2-speed radiator fan with the slower speed provided by the infamous resistor. The two speeds are described as noisy and noisier. The aircon system requires the slower speed running continuously. The engine will also trip this on if it reaches 104C. The faster speed is less used and is primarily for cooling an overheated engine, often after shut-down (heat soak). It will also be tripped on for emergency cooling in the event of the slow speed being inoperable. Since your slow speed seems to be operational, check if it has the 'gold' resistor upgrade in place. Look through the front grill and through the fan blades. You'll see a resistor in the 2 o'clock position on the fan guard. The original, underpowered one is aluminium in colour. The upgrade type usually has a gold anodised finish. It's useful to be able to recognise the two fan speeds (noisy and noisier). The Demist Test will/should trip on the slow speed at will. The high speed can be tripped by temporarily disconnecting the engine coolant temperature sensor and starting it up. TC

23rd March 2017, 21:09	#8
Arryhall Loves to post Rover 75 Join Date: Mar 2017 Location: Biddulph Posts: 486 Thanks: 101 Thanked 145 Times in 90 Posts	So far I haven't driven the car for long enough distances to trigger the higher speed fan, just checked and double checked the operation and yes, air con makes the fan come on. Turn air con off and fan stops. Plus it's been COLD! I'll check the resistor when I get the car back from the mechanic looking at the 3500rpm blip, having the rear seat fitted now it's dry underneath, loose handbrake and a couple of other bits. Also the guy was looking at the noisy fan!