Air con service - compressor clutch failure

mmarks · 27th July 2012, 12:37

Hi all,

In a previous thread I asked about the home/DIY air con regas kits sold in Halfords etc.

Following your advice I ignored these and booked my car in for a full aircon service.

The service took about 1 hour but at the end, they called me up to the car and showed me a pulley right at the bottom of the engine, at the front, on the drivers side.

Apparently this is the compressor and is operated by a clutch mechanism.

On my car, with a torch shining down in that area, you could see the pulley turning a few degrees, then stopping for a second, then turning again a few degrees. This, apparently is why my air con doesn't work.

I was told that there are 2 types on compressor in the 2004 75 diesel, one is over £1000 plus fitting, mine is the cheaper one which works out at just over £500 plus fitting.

As this price is probably more than the car is worth, I wondered if anyone has any suggestions (other than just to live without aircon).

Is the part easy to remove from a scrap car and refit into mine? Is there any way to tell if a 2nd hand unit is serviceable or is there any way to fix the existing one?

Look forward to your responses and hopefully a more positive end to the week!

Michael

SapperGB · 27th July 2012, 13:08

the symptoms you give dont indicate to me that your fan and pressure switch are faulty. someone should confirm that shortly.

Never heard of a £1000+ unit but the price from ECP with club discount is £431 for a new one.

Available on ebay, one going with 2 months warranty for £35 plus postage.
http://www.ebay.co.uk/itm/Rover-75-M...#ht_550wt_1163

or try one of our trusted traders, Seancar should be able to sort you out

SD1too · 27th July 2012, 19:26

Quote:

Originally Posted by mmarks

On my car, with a torch shining down in that area, you could see the pulley turning a few degrees, then stopping for a second, then turning again a few degrees. This, apparently is why my air con doesn't work.

Michael,

Yes, your compressor pulley should rotate continuously, it should not 'cycle' on and off. This could be caused by under or overcharging with refrigerant. Less likely is an unstable voltage from the compressor clutch relay. A faulty compressor isn't even on the radar. Don't agree to replacement.

Are you using an air conditioning specialist or a general garage which also offers air con. service?

Simon.

mmarks · 27th July 2012, 19:34

I used Halfords as they use a machine to evacuate everything and then regas, put a dye in and oil.

mmarks · 27th July 2012, 19:36

I have a multimeter so can check for a stable voltage if you tell me where to connect it.

SD1too · 27th July 2012, 19:46

There's a single wire to the compressor clutch; red I think. Can you get your multimeter probe onto that?

Ask Halfords to confirm the amount of refrigerant put into your system (if I remember correctly it should be 450g +/- 50g). If they prevaricate, take your car away and get a second opinion.

Simon.

mmarks · 27th July 2012, 19:51

Thanks for that. Should I be looking for a steady 12v with sitcom on. Also, which relay controls sitcom so I can test the output of that?

SD1too · 27th July 2012, 20:57

Quote:

Originally Posted by mmarks

Should I be looking for a steady 12v with sitcom on.

With the air con. on, yes. I don't know about the sitcom!

Quote:

Also, which relay controls sitcom so I can test the output of that?

It's in the engine compartment fusebox and should be labelled.

Simon.

mmarks · 27th July 2012, 21:10

Oops, that's predictive text for you. Should have said aircon.

mmarks · 28th July 2012, 13:45

Ok, checked fan working, was fine.
Aircon relay clicks when switched on and, as you described, compressor starts and stops constantly, turning a few degrees for a brief moment, then stopping, then turning a fee degrees again (and so it continues). I couldn't get to the compressor wiring to check the voltage, but the relay isn't switching off and on do I assume it is energised. Where to look next? Halfords wouldn't tell me how much gas they put in, just that 'it was according to specification'

27th July 2012, 12:37	#1
mmarks Regular poster Rover 75 Saloon Join Date: Jul 2012 Location: Southampton Posts: 75 Thanks: 0 Thanked 0 Times in 0 Posts	Air con service - compressor clutch failure Hi all, In a previous thread I asked about the home/DIY air con regas kits sold in Halfords etc. Following your advice I ignored these and booked my car in for a full aircon service. The service took about 1 hour but at the end, they called me up to the car and showed me a pulley right at the bottom of the engine, at the front, on the drivers side. Apparently this is the compressor and is operated by a clutch mechanism. On my car, with a torch shining down in that area, you could see the pulley turning a few degrees, then stopping for a second, then turning again a few degrees. This, apparently is why my air con doesn't work. I was told that there are 2 types on compressor in the 2004 75 diesel, one is over £1000 plus fitting, mine is the cheaper one which works out at just over £500 plus fitting. As this price is probably more than the car is worth, I wondered if anyone has any suggestions (other than just to live without aircon). Is the part easy to remove from a scrap car and refit into mine? Is there any way to tell if a 2nd hand unit is serviceable or is there any way to fix the existing one? Look forward to your responses and hopefully a more positive end to the week! Michael

27th July 2012, 19:46	#6
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,589 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	There's a single wire to the compressor clutch; red I think. Can you get your multimeter probe onto that? Ask Halfords to confirm the amount of refrigerant put into your system (if I remember correctly it should be 450g +/- 50g). If they prevaricate, take your car away and get a second opinion. Simon. __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

27th July 2012, 13:08	#2
SapperGB Posted a thing or two 2005 190 ZT-T SE Join Date: Dec 2010 Location: Dagenham Posts: 1,242 Thanks: 2 Thanked 10 Times in 9 Posts	the symptoms you give dont indicate to me that your fan and pressure switch are faulty. someone should confirm that shortly. Never heard of a £1000+ unit but the price from ECP with club discount is £431 for a new one. Available on ebay, one going with 2 months warranty for £35 plus postage. http://www.ebay.co.uk/itm/Rover-75-M...#ht_550wt_1163 or try one of our trusted traders, Seancar should be able to sort you out

27th July 2012, 19:34	#4
mmarks Regular poster Rover 75 Saloon Join Date: Jul 2012 Location: Southampton Posts: 75 Thanks: 0 Thanked 0 Times in 0 Posts	I used Halfords as they use a machine to evacuate everything and then regas, put a dye in and oil.

27th July 2012, 19:36	#5
mmarks Regular poster Rover 75 Saloon Join Date: Jul 2012 Location: Southampton Posts: 75 Thanks: 0 Thanked 0 Times in 0 Posts	I have a multimeter so can check for a stable voltage if you tell me where to connect it.

27th July 2012, 19:51	#7
mmarks Regular poster Rover 75 Saloon Join Date: Jul 2012 Location: Southampton Posts: 75 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks for that. Should I be looking for a steady 12v with sitcom on. Also, which relay controls sitcom so I can test the output of that?

27th July 2012, 21:10	#9
mmarks Regular poster Rover 75 Saloon Join Date: Jul 2012 Location: Southampton Posts: 75 Thanks: 0 Thanked 0 Times in 0 Posts	Oops, that's predictive text for you. Should have said aircon.

28th July 2012, 13:45	#10
mmarks Regular poster Rover 75 Saloon Join Date: Jul 2012 Location: Southampton Posts: 75 Thanks: 0 Thanked 0 Times in 0 Posts	Ok, checked fan working, was fine. Aircon relay clicks when switched on and, as you described, compressor starts and stops constantly, turning a few degrees for a brief moment, then stopping, then turning a fee degrees again (and so it continues). I couldn't get to the compressor wiring to check the voltage, but the relay isn't switching off and on do I assume it is energised. Where to look next? Halfords wouldn't tell me how much gas they put in, just that 'it was according to specification'