very loud noise by running airco

Teddy · 17th July 2012, 10:49

By auto climate control the airco goes on and off, that looks normal. Everything is working well, and the airco blows very cold air. But when the airco compressor is running it gives a very loud noise, like an airplane is going to start. Inside the car you can hardly hear it but outside people looking very strange and saying, can you put it off, we cant understand eachother. Is this right, do others have the same?
Gerard

Trophy Blue Tourer · 17th July 2012, 11:05

It's probably the Rad - A/C cooling fan!!

You could always get out and check!!

If it's making THAT much noise you might have lost slow speed and it's running on "high" to keep things cool in which case you need to sort it before more damage is caused!!

Do a search on here as there is loads and loads of info on the cooling fan faults!! - easy to sort once you know the fault!!

HTH??

Andy

P.S Different engines have different sensor setting and trigger points so it helps to know what size/fuel engine you have for most engine related questions!! - most people put their car/engine type in the profile section that appears just under your screen name when you post!! mine says MG ZT-T CDTI as an example!!

Dave Goody · 17th July 2012, 11:07

Cooling fan which should run all the time when A/C is on. The fan is very noisy even on low speed. It is possible your low speed not working and the fan is running High speed? Dave

Teddy · 17th July 2012, 15:39

Right, ignition on, demist button on, fan not running, so it is only running on full speed. Looked through the fanblades and see a silver strip about 10 cm. at 2 o'clock. Supposing that is the resistor? I was thinking that that only was mounted by cars after 2003? But, 2 years ago I had a new engine, maybe the garage also changed the fan. who knows. So, al I have to do is replacing the resistor? And if so, I also need to build out the fan? Because I need to replace the radiator, than I will do that the same time. (radiator allready in the house) And at the same time, changing the thermostathouse :-)
Trophy Blue, when you look at my profile, you see everything about my car.

Dave Goody · 18th July 2012, 09:28

Quote:

Originally Posted by Teddy

Right, ignition on, demist button on, fan not running, so it is only running on full speed. Looked through the fanblades and see a silver strip about 10 cm. at 2 o'clock. Supposing that is the resistor? I was thinking that that only was mounted by cars after 2003? But, 2 years ago I had a new engine, maybe the garage also changed the fan. who knows. So, al I have to do is replacing the resistor? And if so, I also need to build out the fan? Because I need to replace the radiator, than I will do that the same time. (radiator allready in the house) And at the same time, changing the thermostathouse :-)
Trophy Blue, when you look at my profile, you see everything about my car.

Yes but when trying to help someone its a pain having to go to their profile to find "What engine"? put it under your name on the left like mine

Trophy Blue Tourer · 18th July 2012, 09:35

Thanks Dave!!!

Dave Goody · 18th July 2012, 09:52

Quote:

Originally Posted by Trophy Blue Tourer

Thanks Dave!!!

Its one of my pet hates!

especially with members of many years

HarryM1BYT · 18th July 2012, 10:33

Quote:

Originally Posted by Teddy

Right, ignition on, demist button on, fan not running, so it is only running on full speed. Looked through the fanblades and see a silver strip about 10 cm. at 2 o'clock. Supposing that is the resistor? I was thinking that that only was mounted by cars after 2003? But, 2 years ago I had a new engine, maybe the garage also changed the fan. who knows. So, al I have to do is replacing the resistor? And if so, I also need to build out the fan? Because I need to replace the radiator, than I will do that the same time. (radiator allready in the house) And at the same time, changing the thermostathouse :-)
Trophy Blue, when you look at my profile, you see everything about my car.

With it set to demist, the cooling fan should run on constant slow speed. If the resistor has failed, the slow speed will not work/ the fan will not run.

In which case, what happens is the fan will intermitantly run on high speed instead, which is very noisy when it runs.

The OEM resistor is not very robust and is a common point of failure. Jules sells a good quality replacement with a higher rating as a ready to fit repair kit, but you source an equally good quality resistor from other sources - from memory I fitted a 0.47 Ohm 100w unit.

In fitting a replacement resistor, you need to make absolutely sure the wires cannot possibly be caught by the fan blades. One member had the wires caught by the blades which did quite a lot of damage.

Teddy · 18th July 2012, 14:37

Trophy Blue, thanks for pointing me, tried many things, hopes it works now.

Dave, please translate in Dutch, so I can understand it

Its one of my pet hates! especially with members of many years

Harry, thanks, just ordered by Jules.

Dave Goody · 18th July 2012, 17:29

Quote:

Originally Posted by Teddy

Trophy Blue, thanks for pointing me, tried many things, hopes it works now.

Dave, please translate in Dutch, so I can understand it

Its one of my pet hates! especially with members of many years

Harry, thanks, just ordered by Jules.

Don't need to now.

PS I was in Utrecht last wed/thurs and it was raining all day, both days like here.

Strangely the only breakdown I have had in one of my 3 75/ZTs was between Den Bosch and Nijmegen [in tank pump], there was an MG Rover dealer in Arnhem who repaired it under warranty and I got to have a good look around Arnhem [the bridge too far] for 3 days while they got the parts
Dave

17th July 2012, 10:49	#1
Teddy Avid contributor Rover 75 saloon 2.5 auto Join Date: Mar 2011 Location: Zandvoort NL Posts: 177 Thanks: 72 Thanked 23 Times in 16 Posts	very loud noise by running airco By auto climate control the airco goes on and off, that looks normal. Everything is working well, and the airco blows very cold air. But when the airco compressor is running it gives a very loud noise, like an airplane is going to start. Inside the car you can hardly hear it but outside people looking very strange and saying, can you put it off, we cant understand eachother. Is this right, do others have the same? Gerard

17th July 2012, 11:05	#2
Trophy Blue Tourer Gets stuck in MG ZT-T Trophy Blue CDTI Join Date: Feb 2011 Location: Milton Keynes Posts: 883 Thanks: 11 Thanked 25 Times in 18 Posts	It's probably the Rad - A/C cooling fan!! You could always get out and check!! If it's making THAT much noise you might have lost slow speed and it's running on "high" to keep things cool in which case you need to sort it before more damage is caused!! Do a search on here as there is loads and loads of info on the cooling fan faults!! - easy to sort once you know the fault!! HTH?? Andy P.S Different engines have different sensor setting and trigger points so it helps to know what size/fuel engine you have for most engine related questions!! - most people put their car/engine type in the profile section that appears just under your screen name when you post!! mine says MG ZT-T CDTI as an example!! Last edited by Trophy Blue Tourer; 17th July 2012 at 11:11..

17th July 2012, 11:07	#3
Dave Goody This is my second home 15 years of 75s & ZTs now an XTrail Join Date: Nov 2006 Location: Danbury, Essex Posts: 3,761 Thanks: 18 Thanked 88 Times in 56 Posts	Cooling fan which should run all the time when A/C is on. The fan is very noisy even on low speed. It is possible your low speed not working and the fan is running High speed? Dave __________________ ZT 190 X Power Grey The Only Colour is this Dark Silver!! When I was a kid I was scared of earwigs because I thought they actually lived in your ears. I was even more terrified of cockroaches!

17th July 2012, 15:39	#4
Teddy Avid contributor Rover 75 saloon 2.5 auto Join Date: Mar 2011 Location: Zandvoort NL Posts: 177 Thanks: 72 Thanked 23 Times in 16 Posts	Right, ignition on, demist button on, fan not running, so it is only running on full speed. Looked through the fanblades and see a silver strip about 10 cm. at 2 o'clock. Supposing that is the resistor? I was thinking that that only was mounted by cars after 2003? But, 2 years ago I had a new engine, maybe the garage also changed the fan. who knows. So, al I have to do is replacing the resistor? And if so, I also need to build out the fan? Because I need to replace the radiator, than I will do that the same time. (radiator allready in the house) And at the same time, changing the thermostathouse :-) Trophy Blue, when you look at my profile, you see everything about my car. Last edited by Teddy; 17th July 2012 at 15:42..

18th July 2012, 09:35	#6
Trophy Blue Tourer Gets stuck in MG ZT-T Trophy Blue CDTI Join Date: Feb 2011 Location: Milton Keynes Posts: 883 Thanks: 11 Thanked 25 Times in 18 Posts	Thanks Dave!!!

18th July 2012, 14:37	#9
Teddy Avid contributor Rover 75 saloon 2.5 auto Join Date: Mar 2011 Location: Zandvoort NL Posts: 177 Thanks: 72 Thanked 23 Times in 16 Posts	Trophy Blue, thanks for pointing me, tried many things, hopes it works now. Dave, please translate in Dutch, so I can understand it Its one of my pet hates! especially with members of many years Harry, thanks, just ordered by Jules.