How to refill air con at home?

I've noticed for less that 15 quid at halfords you can buy a can of refridgerant which should be enough for a couple of fills for a car a/ c.

The question is can you just connect it and fill up or do you need a way of allowing the existing gas to escape to purge the system?

Also is it necessary to buy a pressure guage?

My car's air con has probably not worked in 3 or more years - will it be knackered?

Reply to
405 TD Estate
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Not necessarily, but after such a time, it would be better IMO if you had it checked and regassed professionally.

The system normally contains a mixture of gas and oil. If the oil in your system has disappeared with the gas, getting it running by pressurising with gas alone could knacker the compressor seals.as they'll be running dry.

A professional regas will evacuate the system of any gas remaining, moisture etc. Then refill with the correct mixture of gas and oil, after checking whether the system has any obvious leaks. Replacing the oil could revitalize the compressor seals, which will not have been running since the the system ran out of gas.

You could be wasting your money by trying to DIY with gas alone, as well as possibly causing permanent damage to the compressor seals if it is run with too little oil.

The average cost of a professional regas seems to be about £60, but I have seen it advertised for as little as £45. Mike.

Reply to
Mike G

The compressor seals would be the least of your worries if you ran the system without oil.

A compressor running metal on metal doesn't normally last too long....

Reply to
moray

I've tried these cans for topping up a system that was working but not brilliant, and they are completely useless. Anyhow, you'd need 4-5 cans to fill your A/C system up, and at that price you could have paid for it to be done properly! If done properly your system would be checked for leaks, the leaks found and fixed with a dye, then the system is emptied and refilled under vacuum. You can't really do any of that at home.

If you're mad enough to still try them, all you do is run the system and connect the hose on the can to the low pressure connector, and leave for 5 mins.

Andy.

Reply to
Andy

If you do go down this route make sure they haven't been tampered with and replaced on the shelf. Ones I looked at had been used and were empty. There were no seals on them. Because of this it might be better to use mail order.

Reply to
Dave Plowman (News)

They must be selling 2kg cans now adays then! Typical a/c system contains roughly 700-900 grams...

After 3 years the seals will be dry and leaky.

The can type *top-up* cans are only any good with a working system that must be used with the gauge with CARE.. An overcharge is worse than too little. Also, recharging a known leaking system is illegal.

Their £50 regas service would be much better to try, though i expect your system will need quite alot of work which will no doubt be in excess of what the car is worth.

Tim..

Reply to
Tim..

You may be forgetting that once the seals go, the gas would escape and the compressor would switch off. I agree there is a possibility that the bearings would be damaged, but I think the seals would go first. Either case would mean the compressor would need to be repaired or replaced, neither of which is worth risking IMO just to save a few quid on a regas. That is the point I'm making to the OP. Mike.

Reply to
Mike G

They can recover though, once the compressor is run with oil in the system. The a/c in my car had not been working for over a year when I bought it, because the a/c fan had siezed up. I had it regassed, and it appeared to be leak free. Still didn't work, because the siezed fan prevented it from being switched on. The a/c guy bypassed the fan, just to check that everything else was OK, and it was, but until the fan was replaced, it still couldn't be switched on. I replaced the fan a few days later, but it still didn't work. When it was checked, all the gas had leaked away. Had it regassed and it has now been working perfectly for over 6 months. I suspect that the first fill would have been OK had the system allowed the oil to work on the seals with the compressor running. Only time will tell just how well the seals have recovered their elasticity.

Based on my own experience, I'd be inclined to be a bit more optimistic. Even if the compressor is knackered, working s/h ones are not that expensive. Mike.

Reply to
Mike G

As far as I know, no system has a feedback loop to tell if the fan is working or not. The one on my E39 has never worked, but the AC does. I just switch it off in the odd traffic jam. I've had a new one waiting to fit for a couple of years - if I used the car a lot in places where you get jams it would have been done by now. ;-)

Reply to
Dave Plowman (News)

Strange. I know that is the way the a/c in my E34 works. The fan is knackered, and like yourself I have a fan waiting to fit. In the meantime the a/c is working fine. All I know is that when my E39 was first regassed, it didn't work. The a/c engineer said it was because the fan wasn't working. When the fan was replaced, and the system regassed it did work. I know my E39 is an earlier one than yours. A '96, so maybe earlier models were wired slightly differently. Just a guess.

Just bought a later 528i BTW. A '98. Lower miles and with much better paintwork. Has strange brown tinted door mirrors. Would that be in keeping with the auto dimming type? Mike.

Reply to
Mike G

I reckon they did some more work. The control circuitry for the fan can give trouble too and it's possible a fault there would stop the system working.

I didn't know they did auto dimming door mirrors. I have that on the interior one - and the glass looks a normal colour.

Reply to
Dave Plowman (News)

You could be right, although I was only charged the std price for a regas.

RTFM. Sorry. Couldn't resist.:-)

Auto dimming door mirrors come with the 'Mirror package' In the later Owners Handbook I have, it's mentioned on page 53, under 'Mirrors'. In the earlier HB it's on page 48.

I haven't picked up the 'new' car yet, so I can't check if it has the mirror folding button on the armrest which would confirm whether it actually has the mirror package fitted. Has a glass sun roof and PDC though, which are nice additions to the older one.

I have that on the

Both of mine have auto dimming interior mirrors, with the built in sensor, which is certainly not present on the tinted door mirrors, but was thinking the auto dimming on them might be controlled by the interior mirror.

I seem to be aquiring quite a stable. :-)

'94 E34 525i. '96 E39 528i '98 E39 528i '85 SD1 Vitesse. Mike.

Reply to
Mike G

Hmm I wouldn't mind spending 50 quid on a regas to get it working but it sounds as if there is little chance of that suceeding. How would I tell if the compressor fan is working OK and I guess I could check to see if the system still has any pressure and maybe try put some air in to see if it holds pressure as an indication if it would work?

Reply to
405 TD Estate

I bought a bigger 40 quid canister for my BMW, with a pressure gauge and although it wasn't enough to fully charge it it did work - for about a day or two.

If the hot side of the aircon gets hot then the fan should kick in.

Reply to
adder1969

AFAIK a competent a/c engineer wont regas it if there are any obvious leaks. Presumably if it is not regassed, the cost will be less than for a service that includes gas.

As I see it there is no way without the right equipment, to properly check it yourself.

My advice would be to either do the job properly, and have it checked by an a/c engineer, or forget it.

Personally I don't think £50 is a lot to pay to possibly have a working a/c system, or at least to know what is wrong with it.

Forget any idea of regassing it yourself. I have no doubt it will need new a/c oil as well as gas for it to have any chance of working long term.

The compressor might be OK, but just regassing the system and running it without knowing if is okay for oil, you stand a good chance of damaging the compressor bearings and/or the seals permanently. Mike.

Reply to
Mike G

The air-con top-up canisters sold by Halfords (£39.99) do not just contain refrigerant - but also all the other necessary ingredients such as lubricating oil, system cleanser, and minor leak sealer.

You can see the 'Measure and Charge' kit they sell here:

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Uno-Hoo!

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Uno-Hoo!

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