Cooling Fans

[stevetreacy]

Hi All,

What is the easiest way of testing my Cooling fans without Tech2.

Thanks

steve

[sgould]

They should come on at start-up if the aircon is on.

Or leave the car idling and they will come on and off as necessary.

[stevetreacy]

Hi,

Yes thats as I thought. My AirCon is playing up. Had it evacuated and refilled, comp kicks in but still no cooling. Fans wont come on at all, even when idling for twenty minutes? Temp gauge was mid way as usual. Have checked all fuses and relays. Im thinking that if fans dont cut in this is why AC wont work. Will get it hot later today on way home and leave running to see if they kick in. Will have to get fan issue sorted first I think before tackling AC.

Thanks

steve

[Steve440]

You might have a big leak in your A/C and all the new gas has leaked out. I have seem cars that will hold a good vacuum once charged loose all the refrigerant in a couple of days.

As far as the fans go if the A/C system goes over pressure because the fans are not on it will keep cutting out so it does not burst any pipes. No A/C if not enough gas or to much pressure and once the system starts to pressurize it will put the fans on to maintain a safe pressure and keep the system as efficient as possible.

Steve

[stevetreacy]

Hi,

Cooling fans all working OK. I just hadnt got it hot enough. AC system pressurised with Nitrogen at 80PSI for 2 hours. No drop in pressure, so I assumed it wouldnt leak. Vacuumed out for about 1.5 hrs then refilled with 875grms of gas. Comp is cutting in but it just doesnt sound right somehow. The click is muted and I cant actually here it whining like it was. Im assuming pressure sensor is Ok otherwise comp wouldnt try to click in at all. New expansion valve fitted 3 years ago. Not looking good for my compressor at the moment. Can the Electro-Magnetic clutch stick?

Thanks

steve

[Steve440]

Did they not fit a new filter? if your expansion valve got clogged up there must be some rubbish in the system. Its quite normal on older vehicles with A/C, its a combination of rust, dirt,oil and moisture.

With the system running you should feel one of the main pipes getting warm to hot and the other should be almost ice cold. If your not getting this it could be a blockage or as you say the compressor.

Try putting a +12v straight to the wire on the compressor clutch, I have seen systems especially with automatic climate come to life using this method.

Steve

[Audax]

I've known a 9-5 that held a good vacuum when cleaning the aircon system out and took a charge with no leaks until the compressor ran when you could visibly see the gas leaking out. As suggested +12V to the compressor to see if it cuts in, it might have broken itself up internally which I've seen a few times too.

[stevetreacy]

Hi,

No the reciever drier unit was not replaced as far as i can tell from appearance, service records and bills. I vacuumed both low and high sides so am hoping it is clean. Will try direct feed to clutch and see what happens. I still have all the gas and 40 PSI on low side. Didnt measure high side. Am convinced its not cutting in properly. A Tech at work thinks I may have poor earth connection. Thanks for all your advice.

steve

[phoenix]

I've known a 9-5 that held a good vacuum when cleaning the aircon system out and took a charge with no leaks until the compressor ran when you could visibly see the gas leaking out.

Not uncommon- a seal or leak may be held closed under vacuum but allow gas to escape under positive pressure. I've had this on mine. However in this instance there's been a nitrogen pressure test.

The 9-5 compressor is variable displacement and doesn't come in with the traditional "thump" IME

[stevetreacy]

Hi All,

Tried after work today and still the same, however I removed headlight and could see better and the clutch was not engaging but trying to. Checked voltages and earthing and all OK. Gave the clutch mech a little dose of WD40 and away it went. 5 deg C at vents and all is well again. Thanks for all your advice, I was dreading the thought of replacement.

Regards

steve

[Audax]

Not uncommon- a seal or leak may be held closed under vacuum but allow gas to escape under positive pressure. I've had this on mine. However in this instance there's been a nitrogen pressure test.

Nitrogen doesn't always tell the whole story either though. I've nitrogen tested cars and still had them lose all the gas after a few weeks.