BXProject

[smiffy]

I have some questions about airconditioning.

I've never owned a car that has it before, so I really don't know what I'm talking about.
the Air-con on my car doesn't work at the moment, so I need to ask ho to check for leaks, what type of refrigerant it might have, how easy/expensive it might be to fix, or convert to a newer typ gas....etc.
Obviously it's not so important right now, but I like to be cold when the sun comes out!

[Vanny]

it will be either an R12 or R134a system, but it could have a huge range of refridgerant types in it, if it indeed has any gas in it at all. These are the first things to find out;

What system is it? (screw over or quick release filling ports)
Does it have any gas? (a quick press on the schraeder valve in the filling port should do the trick)

If its R134a and it has any amount of gas in it, then i'd head straight over the kwik fit and let them gas it up. Do NOT allow them to put leak detector in unless they can prove that it can't hold a vacuum, and i mean hold 2torr for 10 minutes, not just point at the guage on the charge rig and go 'see it wont go to zero' as the guages on the charge rig mean nothing at that sort of pressure.

If its go no gas, then i probably has a leak.

Leak detection is done by pressurising the system with oxygen free nitrogen (OFN) but basically you need an inert gas that you can control the pressure to 10bar or so (is that a welding bottle i see there or are you just happy to see me). Then find and fix the leak.

If it is an R12 system (which i doubt, these days most have been converted) then you need to buy a sealing ring pack and change all the seals (being carefull to oil the seals before fitting), drop the compressor and flush the oil out, replacing it with ND8 or similar. Then you need to do an inline flush of the system if you suspect it has been open (i run white spirit through at high pressure ). Then cobble it all together and check of leaks again. If there are no leaks then you can cart it off to kwikfit for filling and change the receiver/drier just before you go.

Hunt around and you'll get a reciever/drier for around £15 (old new stock) and the seals are around 20 to 40p each, or the kit is £14ish from citroen.

[docchevron132]

It's an original system, dont think it's ever been apart by the looks of it.
Run out of gas I'd say, the compressor wont kick in when operated, nor do the fans come on when switched on.
Infact it does nothing at all.

[mat_the_cat]

If the fans don't operate it's more than a lack of gas IIRC. The fans should still operate even when system is empty I think, need to dig out the wiring diagram to be certain though. I have it as a PDF if you want Smiffy, also a Sandon manual for the compressor.

[Vanny]

Mat, do you know there are 5 different wiring diagrams for the AC system?!? Thats assuming the 5 i have are the complete set. There are two very different systems fitted to early and late Mk2's.

I agree that if the fans aren't coming on that its nothing to do with refrigerant, that will be a wiring issue, and dependant on the system type, id suspect the blower relay overide. I'd check to make sure the fans will run normally!

[mat_the_cat]

Mat, do you know there are 5 different wiring diagrams for the AC system?!?

Nope
All I know is the one I have matched the donor car for my system, which was a 1991 model. Must have been lucky! Are they significant differences do you know?

[Vanny]

massive differences, not only in terms of layout, but also wire guage and colour! Had me stumped for quite some time, then i realised i had lots and lots of diagrams. It didnt help that of the two donor looms i had, i didn't know where they had come from!

[docchevron132]

This car is 91, I know nothing of the wiring, soince the AC set I have is aftermarket / early P1 valver and is totally different.

Good point though, so the fans work at all?

[mat_the_cat]

I'll email through the stuff I have Chris (I don't know Smiffy's address). Assuming Citroen were consistent with what wiring for which years (ha!) it should match what you have on Smiffy's...

[docchevron132]

Smiffy's addy is easy:
Smiffy,
somewhere in s***h east Bristol,
near the chinese.

That should do it!

[Way2go]

somewhere in s***h east Bristol, near the chinese.

Socialising with them, or buying it?

[smiffy]

Something missing there....

somewhere near the chinese....takeaway!

[Fish_Botherer]

One quick question - does it have the two slider controls on the upper-middle console above the radio, or an on-off toggle switch probably sited on the handbrake console?

As said before, the two Ventilation fans in the scuttle should be completely independent of A/c functions on a car with the slider control set-up. When you can get these working, you'll wonder how you ever managed with a poxy single fan set-up .... and start replacing alternators more often.

[mat_the_cat]

Ahhh. I'd assumed the fans were referring to the radiator fans than should come on when A/C is turned on. As for the alternators, mine (11 y/o, 130k miles) failed soon after I installed it, but the replacement (new) has been fine for the 4 years/60k miles since. How many alternators did you & Tom have to fit?

[docchevron132]

I meant the rad fans yes, they dont operate when the AC is switched on, and I'm led to believe they should.
The blower fans work.

[Fish_Botherer]

I fitted (or rather Tom revamped for me) one alternator in 3 years. before that, I think Tom got through a few, though the car was used much more heavily in his ownership. I also suspect these were not alternators uprated to published a/c spec....

Matt- you're perfectly correct to weigh in with rad/condenser fans where I've weighed in with twin ventilation fans. It's just that when the twin vent fans work, they make such a difference to ventilation that people normally comment on them....

[mat_the_cat]

Yes, they should - I'll disconnect the pressure switch on mine to hopefully prove they still should work even with an empty system. If not then one dead fan would prevent either of them running on the slow setting (A/C on and/or engine hot) but would still have 1 running full speed (A/C over pressure or engine very hot).

EDIT - I was replying to Doc with the above
My replacement alternator was the HD (85A?) alternator, if that would make the difference, but would have thought that things like headlights, HRW etc would have more of an effect on current draw. Also, my expectation is that if there is too much current for the alternator to cope with, it would simply flatten the battery rather than kill the alternator?

[Fish_Botherer]

OK - blowage there, but rad fans don't come one. Apologies for muddying waters. So the A/C compressor doesn't kick in either, I now notice when looking.

I seem to recall the compressor clutch won't be triggered if there is no pressure or low pressure in the system - hence Vanny's list of checks. My instinct though says you also need at some point oto check whether the compressor is either seized or 'sticky' through sustained lack of use. This can be done when checking out all the other components of the system ... we could be talking quite a few years of inactivity here.

But why listen to me, I Just used the system, and never had to debug it in the way that Mat or Vanny for example, have done. I drove the donor car for Grolliffe with inactive A/C around for a while before that system was transplanted. It took a fair amount of component replacement on the transplanted system to get it right. Tom will of course know, but the condenser and drier certainly had to be replaced, though I can't remember if the compressor is the original or not.

[Vanny]

DLM, the rad fan supply and compressor clutch supply are connected. If the rad fans aren't coming on when AC is switched on, and the rad fans do work when the engine is hot, then the AC compressor will not be getting a supply. Its a much easier test to leave the car to idle for 20 minutes than to start fault finding electrics with a meter. And I'm pretty sure even smiffy can stand next to a car with the engine running for 20 minutes to see if the fans come on.

The air flow from the dash vents is not generated by a fan (blades on a central mount, with axial air flow) but by a blower (cage of blades with side intake). I have no idea when or why this differentiation came about, but even in the haynes manual it refers to 'blowers' and 'fans' as very separate entities. I suspect air flow volume also has something to do with it.

This is the notation i try to stick to;
Rad cooling = fans
Cabin cooling = blower

The ventilation blowers are totally independant of the AC system, so there functionality (or not) is in no way indicitive of AC system performance.

[Philhod]

You are dead right there young man Rads have always had fans, ergo fan belt.
Heaters have always had blowers.