P38A Air con regas

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AndyF07

Active Member
Posts
134
Location
UK
Hi,

A bit of advice would be much appreciated. My air con on 2002 P38 hasn't worked for a few years but as it has generally been a "working" vehicle ( and fantastic ) it wasn't a priority. Over the last year I have spent many enjoyable hours getting her back to her former glory. The last bit of my project is the aircon. There are no codes for the hevac system and no book symbol.

My question is whether there are further tests and checks I need to do before taking it to be re-gassed. I know little about aircon systems and don't want to waste time and money on a regass only to be told of leaks, clutch issues etc I could diagnose myself.

Your experience and knowledge is much appreciated :)

Thank you
 
Is the pump free? Ie can you turn the middle bit by hand?
Why didn't it work now? An Aircon garage will put a machine on it to pull a and hold a vacuum to check for leaks, then fill check again under pressure before regassing.
If the system has been open to the atmosphere then you'll want to hold a vacuum for a long while to get all the water out.
Ideally you'll want to get all the old oil out and refill with the proper amount but i don't know how you do that. The old stuff can go acidic and gunky if it's been left for a long time
 
If you press the air con valve then first you will see if any pressure left in it, of none then you will have a leak, if you can pump it up with air then you have a chance to find the leak, the condenser on my car went last year and leaked the gas away , a new condenser and re gas now working fine
 
kermit_rr said:
Is the pump free? Ie can you turn the middle bit by hand?
Why didn't it work now? An Aircon garage will put a machine on it to pull a and hold a vacuum to check for leaks, then fill check again under pressure before regassing.
If the system has been open to the atmosphere then you'll want to hold a vacuum for a long while to get all the water out.
Ideally you'll want to get all the old oil out and refill with the proper amount but i don't know how you do that. The old stuff can go acidic and gunky if it's been left for a long time
Click to expand...
Thank you for your help :) I really have no idea on aircon systems although happy to learn. My motto is how hard can it be ;) Having said that would you recommend researching the topic and having a go or is it a big pain in the @@@@ and simpler to pop to a garage to at least diagnose ( I assume ) what is wrong if anything ?
 
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I did a lot of research, my p38 had been open to the elements for years. Pumping it full of air will introduce moisture, the only way to get it out is with a sustained vacuum. Garages use nitrogen to pressurise as it's dry and better at finding leaks than air. Easiest to get a garage to check it first imo
 
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kermit_rr said:
I did a lot of research, my p38 had been open to the elements for years. Pumping it full of air will introduce moisture, the only way to get it out is with a sustained vacuum. Garages use nitrogen to pressurise as it's very and better at finding leaks than air. Easiest to get a garage to check it first imo
Click to expand...

Thanks for the advice @kermit_rr. Cheers :)
 
Do a search on here.
There are many Fred’s on AC. Some stop working and still have gas so there are a few checks you can do first.

But a gas/regas/leak at your local place is not break the bank money to know where you are as a starting point.

As much as I don’t agree with it pushing the fill valve tit to see if you have gas is a test ;) To see. Not for me though and don’t look at it if you do.

it’s probably the trianary switch down at the drier behind the bumper hidden behind everything :).

J
 
Do you have a nanocom? Think that tells you the status of the pressure switch. Ie it can be full of gas, but if the switch doesn't work, it will think there's no gas.
The book symbol isn't lit by Aircon problems so that's no help to you
 
Bridge the clutch if it gets cold it’s got gas, don’t do it for long the pipes will tell you cold and hot :)

J
 
kermit_rr said:
Do you have a nanocom? Think that tells you the status of the pressure switch. Ie it can be full of gas, but if the switch doesn't work, it will think there's no gas.
The book symbol isn't lit by Aircon problems so that's no help to you
Click to expand...
Unfortunately it doesn't, all you can see in Nano is AC request and AC grant
 
marjon said:
Bridge the clutch if it gets cold it’s got gas, don’t do it for long the pipes will tell you cold and hot :)

J
Click to expand...
yes, if you undo the round connector all you need is a 9v battery across the two connectors to pull the clutch in. I suppose that with no book symbol you will probably be fine. I'd just go ahead and get it refilled. They shd vacuum test it before refilling anyway.

Once they have refilled it the fitters will want to turn on the ac to test it. At this point, if the clutch does not pull in, ATS will want to drain it, whereas Kwik fit will leave it filled if you ask nicely, and pay...(ie go to Kwik Fit in the first place). That was my SW London experience, anyhow. If the clutch does not engage while the engine is running, and with HEVAC at LO then Plan A: whack the clutch briefly with a spanner - odds are it will start spinning, or Plan B: bridge the condenser at the round connector with a 9v battery. You do not have to start running 12 v wires in from the fuse box to the condensor, it will work, but it's unnecessary and no garage would ever let you start doing that on their premises anyway - just a good 9v battery is fine.
 
On later cars, there is no book symbol for non functioning aircon due to lack of gas. On the three I have dealt with, it was the condenser leaking.
Pressing the valve to check for gas is dangerous, gloves and eye protection should be used, the gas can penetrate the skin.
Sticking or slipping clutches are not unknown either.
On early cars, the clutch is driven direct from the HEVAC, on later car there is a relay, so that may be worth checking.
 
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