Climate Woe

[r1150gsclark]

Thought I might have a leak in the aircon in my recently purchased 99 D9 110 HDI, after asking the seller to check and regas the system, so took it to an aircon specialist in Oxford for a service. Apparently the system holds around 650g gas, so imagine my surprise when they actually recovered 1400g from the system!!! Now the specialist has said that it can cause problems with pressure switches, compressors etc, and advised me the compressor was not kicking in, so needing a return visit for a diagnostic, but after about 30 mins driving, I suddenly started getting very cold air and demisting. I am returning for the diagnostic, but anybody suffered similar, or any ideas what might be faulty?

Any ideas would be appreciated

Garry

[teamster1975]

If the system is holding its pressure then it could be the pressure switch.
Puggy had to have the compressor replaced on his after much grief with repairs, he's got the hdi 90.

[Doggy]

Garry,

Mine did something similar when I replaced my condenser - it passed the vacuum leak test OK, (no gas recovered as it was empty), then had the normal charge added. Started her up & the compressor wouldn't kick in.

Suspecting I had an electrical problem to sort at my leisure, I 'forced' the compressor clutch by connecting it direct to 12V. (Thinking I'd make sure it runs cold, then check for dodgy relay or whatever). This worked, but to my surpise, from then on it has worked perfectly by itself.

I think I know why. There is a non-return valve fitted between the condenser & the pressure switch, (probably so you can change it without losing the gas). If there is no gas pressure at all, (i.e.when it's empty), the ecu won't operate the compressor to save it running dry. I reckon you have to get a little pressure in there somehow before it will work normally.

(The pressure 'switch' is actually a pressure sensor as the engine ecu 'knows' the refrigerant pressure and you can watch it changing with engine speed / thermal load, at least on later D9's).

[r1150gsclark]

Thanks for the advice guys, am hoping it is something like the pressure switch, but having so much gas in didn't help!!
Dogslife, how do you force the compressor exactly? My compressor is a Delphi. I might give it a go and see what happens.

[Doggy]

Mine has a 2-pole connector for the clutch.

One pin is the earth & will measure almost zero resistance to the outer casing of the compressor, the other, (positive), showed about 8 ohms IIRC.

If you apply +12V to the positve, (carefully observing polarity), you should clearly hear the compressor clutch operate. (I had a practice with the engine stopped before trying it for real).

[r1150gsclark]

The compressor is now kicking in, and I didn't do anything!! Will still get it checked out, but it appears to be now working. This car is really developing a mind of it's own!!
Thanks for the advice guys, fingers crossed that is now it.

[Doggy]

Excellent stuff!

(Must confess I wasn't convinced about spreading chicken entrails round the garden at moonrise while chanting the Lord's Prayer backwards in French, but you gotta admit it works a treat).

[FarmerPug]

Excellent stuff!

(Must confess I wasn't convinced about spreading chicken entrails round the garden at moonrise while chanting the Lord's Prayer backwards in French, but you gotta admit it works a treat).

he can speak french electrics

[r1150gsclark]

I think the French for 'Electrics' is 'Merde!'

[FarmerPug]

isnt merde damm, or sh*t excuse my french.
since them translators dont speak such foul language how in french do you tell someone to feck off (only with feck spelt correctly).

[r1150gsclark]

'Merde' does mean s*it, and to answer your other question, try 'Va te faire foutre', hope this helps

[r1150gsclark]

Took the car to the Aircon specialist, and found that the compressor is working intermittently, but because he did not have the correct wiring diagram, he could not identify the problem, so have a auto electrician looking at it on Thursday, plus I now have a leak in the condenser, bloody brilliant!!!

[Doggy]

Bad luck - leaky condensers are all too common unfortunately.
If it's any help the compressor clutch is switched by one the relays in the BSI, (at least it is on mine). I read a howto on swapping the relay, (but can't remember if it was on here or the coupe forum, here I think).

Personal experience suggests the system will switch off the compressor in the event of low gas pressure and that might be all there is to it. I would change the condenser first and see if that cures it.

If this idiot can do it

[r1150gsclark]

Thanks Dogslife, I have an auto electrician coming tomorrow morning, will get condensor done next week. Seems strange that the leak is only apparent now after it had the correct amount of R134a (650g) and not when it had 1400g in it!! The condensor lost about 200g over 5 days, and it has been regassed. Does anybody know the low limit cutoff for the compressor is?

[r1150gsclark]

Seems like the pressure switch is leaking through to the multiplug!! Hardly surprising seeing the gas originally in the system was over twice the specified amount. And the condensor is leaking on a couple of entry points. So a new condensor and pressure switch have been ordered from http://www.autoairconparts.co.uk for around £130. Hope that gets it sorted once and for all