Hi all,

 

First of all, I'm sorry if my grammer isn't right.

 

I have a 2006 MkII Octavia 1Z5 1.9TDI

My A/C Compressor Clutch isn't engaging since 3 months ago I've bought the car. No matter A/C On/Off, it doesn't spins. When I turn A/C ON, there is no click or triggering noise neither.

3 weeks ago, I discovered a leak at the top of the fuel filter housing and I spray with a brake cleaner spray to clean arround it, right after fixed the leak. And recently noticed, it is now spinning always together with pulley. Again, no matter A/C On/Off, no click or rev change. Not cold airflow too. If I DIY replace only the magnetic clutch and go to service to refill r134a will cure it or not?

 

Any thoughts?

 

Best Regards

 

 

 

 

Edited 14 January, 20197 yr by sertacgencer

The compressor in your car is of the variable displacement type and has no magnetic clutch as found on older vehicles.  The output is controlled electrically to a solenoid valve on the compressor.

Am going through the same troubles with the same age car, as has been said there is no clutch on our vehicles but like you I initially thought that my (non existant) clutch was not engaging.

 

It will be one or more of the following.

 

1- System needs recharging, G65 pressure sensor not seeing enough pressure so controller will not actuate the compressor control valve (electrovanne/pressostat in French)

 

2- G65 pressure sensor failed (mine had), its caused by condensation build up just like the fuel filter housing problems, sensor can be replaced without draining and recharging system, some cheap E-bay ones dont work, the first one I bought didnt.

 

3- Compressor control valve faulty, usually stuck and can often be cleaned up and released, new one quite cheap.

 

Mine had fault 2 and through prolonged inaction fault 3, I cleaned up the valve and thought it was working but had nothing to judge it by, after a regas the system still does not pump so I have a new one on order, when it comes and assuming it finally solves my problem I will update this thread.

 

Editted.

 

4th option will be pump failure which would normally be evidenced by the shear plates on the pulley coupling having broken.

Edited 14 January, 20197 yr by J.R.

On 14/01/2019 at 12:09, J.R. said:

Am going through the same troubles with the same age car, as has been said there is no clutch on our vehicles but like you I initially thought that my (non existant) clutch was not engaging.

 

It will be one or more of the following.

 

1- System needs recharging, G65 pressure sensor not seeing enough pressure so controller will not actuate the compressor control valve (electrovanne/pressostat in French)

 

2- G65 pressure sensor failed (mine had), its caused by condensation build up just like the fuel filter housing problems, sensor can be replaced without draining and recharging system, some cheap E-bay ones dont work, the first one I bought didnt.

 

3- Compressor control valve faulty, usually stuck and can often be cleaned up and released, new one quite cheap.

 

Mine had fault 2 and through prolonged inaction fault 3, I cleaned up the valve and thought it was working but had nothing to judge it by, after a regas the system still does not pump so I have a new one on order, when it comes and assuming it finally solves my problem I will update this thread.

 

Editted.

 

4th option will be pump failure which would normally be evidenced by the shear plates on the pulley coupling having broken.

 

It seems to be a common fault. How did you diagnosed/fixed the ac system. Is it DIY friendly? or car mechanic?

I guess the logical way must be recharging the system first. Then, G65 sensor, clutch, valve etc.. if needed.

Do you have engine running temp. low or max 70C issue? Probably thermostat stuck open. Damn, to do list never ends on a VAG. 

The sensor can be removed and changed without losing refrigerant pressure so I would remove it first and not pay out for a recharge that may not be needed (mine was in fact fully charged) you will probably see that the sensor body has corroded and  split, if the contact pins are corroded or the connector wet/greasy inside it may well have leaked refrigerant.

 

You could try a tiny poke on the schrader valve underneath wearing gloves to see if there is any pressure but I should not be suggesting that to anyone in this modern world but I did.

 

I then bought and fitted a new sensor and if you are lucky then the system should spring back to life if there is sufficient gas/refrigerant within, I was not lucky but by using VCDS I could see that I had 4 bar pressure on the high pressure circuit which did not change when the engine was running, I also bought a set of aircon guages, around £30 and they will tell you the same thing without the expense of VCDS, they also told me that the pressure was the same in both circuits and the HP one did not rise with the engine running leading me to believe that the aircon pump control valve was stuck.

 

To replace the does need the gas removing and for environmental reasons you should really get whoever will be doing your eventual recharge to bleed out the old gas and recover it, its costs a fortune so they might be amenable, if not the guage set will enable you to do it whilst simultaneously making a hole in the ozone layer!

 

I thought that I had got my valve working and then paid for a regas but still no pressure in the HP circuit, they sucked back the gas and said they will recharge it for free once I have fitted the new valve which I am still waiting to be delivered.

 

Mine will be a long, costly and maybe even fruitless battle, I might yet need a new compressor  but for the majority of people simply replacing the pressure sensor will bring back the AC operation, I think mine had been left non functioning for a very long time making the control valve stick.

I also learned that VCDS shows absolute pressure whereas the guages indicate guage pressure meaning that VCDS said 4 bar and the guages showed 3 bar.

You mean relasing some gas out on low pressure port right?

 

9 minutes ago, J.R. said:

I also learned that VCDS shows absolute pressure whereas the guages indicate guage pressure meaning that VCDS said 4 bar and the guages showed 3 bar.

 

Good to know. Thanks mate keep me updated. Cheers