Citroen XM Forum

I have been reading and watching a lot of tutorial videos on t net about A/C systems and armed with a tiny bit of knowledge I feel comfortable enough to have a bash at this air con thing now I think, just bought a very nice nos manifold for R12, need to beg borrow or possibly steal a VAC pump now and I'm ready to roll.
Doing the internet warrior thing I have learnt enough to know what my system needs in the eyes of the super anal a/c mechanic is the best part of a days work, flush the hoses, condensor and evapourator (not the pump) start a fresh knowing there is no oil so I can get the weights/volume right and not be mixing oils, get the new dryer on, VAC it down for at least half an hour, stick a little dye in for future trouble shooting and gas it up to bask in my own super chilled glory or weep while reflecting on my own stupidity.
Apparently the refrigerant grade propane has the methane removed compared to the weapons grade BBQ propane, got a few 47kg propane bottles left from the gas business I shut down a couple of years back, its tempting and obviously would work as I would guess many gasses would it would niggle at me knowing there are farts in the a/c system and I can't seem to find a reason it they remove it from the refrigerant grade propane.

Here goes..............

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methane added to BBQ propane = stinks if there's a leak, no methane = no smell. at a pure guess that's the difference, the smell being added as a "safety measure" on the stuff available to joe public? Re farts in the AC, that made me nearly spit out my black espresso flavour magnum!

You haven't got time for espresso magnums, you've got a car to put back together!

Right, what I need is Citroens a/c specs, there must be something out there in old service docs, I need original R12 charge weight and oil quantity, there should be oil quantity for each individual component so you can add the right amount, there should even be Citroen updates for upgrading from R12 to 134.
Russ if your reading did you re create an a/c sticker for the slam panel, mine has never had one, I think, not in my ownership anyway.

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ekjdm14 wrote:methane added to BBQ propane = stinks if there's a leak, no methane = no smell.

How is that, given that natural gas (methane) has smell added to it to make it safe.

Hours of boring training told me propane and butane is odourless and they added a stenching agent, didn't go into what it was, turns out according to the www. Its called Ethyl mercaptan, which must be farts right? They bottle farts and put them in LPG, natural gas, propane and butane..............

What sort of vacuum do you think one of the servo assist/egr pumps from a diesel engine could generate?
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Any secondary school/college physics lab will have a vacuum pump amongst its kit - electric or hand - capable of a high level of evacuation.

Or use the air intake of a workshop compressor, if you can pipe into it.

Dean wrote:You haven't got time for espresso magnums, you've got a car to put back together!

Right, what I need is Citroens a/c specs, there must be something out there in old service docs, I need original R12 charge weight and oil quantity, there should be oil quantity for each individual component so you can add the right amount, there should even be Citroen updates for upgrading from R12 to 134.
Russ if your reading did you re create an a/c sticker for the slam panel, mine has never had one, I think, not in my ownership anyway.

D

Guess wot... Yep I have been reading. Interesting... Brave!

Now interestingly I have a green sticker for my aircon on my car. It's been converted from one system to another. Don't ask me numbers, but it's got R something on it. Either R12 or R134 ...Will check tomorrow. But yes, I can create any AC sticker... Even a non citroen bespoke one. Not sure Citroen actually fitted AC stickers.

What ever my car now has, it's flipping freezing. Last summer when I bought the car off Rob, the drive back home from the national was quite a hot day. I didn't even have it on 16 degrees and I had a cold nose and had to switch it off!

OK I can do that, here is one for you, why in all the home mechanic you tube video I've seen do they perform the evac for 30 mins or so but leave the pump running for 30 minutes, surely once you have sucked the atmosphere out and got to as great a VAC as possible that's it, shut the fill valve and turn the pump off, once you have reached Max VAC you can't pull anything else out?

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This explains it...
http://www.freeasestudyguides.com/air-c ... ation.html

Dean wrote:OK I can do that, here is one for you, why in all the home mechanic you tube video I've seen do they perform the evac for 30 mins or so but leave the pump running for 30 minutes, surely once you have sucked the atmosphere out and got to as great a VAC as possible that's it, shut the fill valve and turn the pump off, once you have reached Max VAC you can't pull anything else out?

D

Any water in the system (especially in the drier) takes time to evaporate and work its way to the vacuum pump.