This is a bit of an aside from my M57ness, but I thought I'd share it anyway in a new thread.

A nice example of why you should keep your A/C on all year round. This compressor has only sat idle for about two years - the system didn't leak at all before the car was written off.

Where the seal hasn't been kept under pressure with the gas and oil in the top discharge plate, moisture has crept in corroding the aluminium surfaces against the seal. A vacuum pulled it shut, but then the high pressure of the discharge side of the compressor has just started to blow past the corrosion.

Thankfully the surfaces on the compressor side and the seal (still nice and pliable) cleaned up okay, and the top plate from the used replacement compressor also cleaned up nicely. Now to put it back together again and wiggle it back into place.

Totally agree, particularly on the P38 (and quite a few other cars) where the system is designed to be on all the time and it regulates the temperature by mixing hot and cold air. When I was working we had a fleet of Astra vans which were replaced after 5 years with Kangoo vans. Both had the manual AC on button and I switched it on and left it on all the time, whereas others only switched it on when it got warm. On both the Astra and the Kangoo, I was the only one that didn't have to get the system re-gassed when summer arrived. It's like everything else on a car, if you keep using it, it keeps on working, if you leave it, chances are it will stop

Yeah - but you'll always get those that think turning the AC off will save them a tiny bit of money in fuel (usually offset nicely when it needs repairing as a result) or those that just don't think AC is ever necessary...

Well - to the latter people, that's your opinion and you can keep it, I hate being too hot.

Part of the problem is if you don't use the A/C the seals/o-rings can shrink of course (and just re-gassing may not fully resolve that issue). If you have not run the A/C for a while a vacuum test is advised before re-gassing too.

For those thinking the A/C is not needed in the winter running it now and again (eg. every week) can be important.

davew wrote:

Part of the problem is if you don't use the A/C the seals/o-rings can shrink of course (and just re-gassing may not fully resolve that issue). If you have not run the A/C for a while a vacuum test is advised before re-gassing too.

Not advised, mandatory. Process is recover any remaining refrigerant, pressure test with Oxygen Free Nitrogen to 10 bar, vacuum out, then, and only then, as long as the pressure test and vacuum don't show any leaks, regas. That's what the automatic machines do and that's why it takes about an hour as they put the Nitrogen in and wait to see if the pressure drops.

In winter it kicks in automatically if you put the HEVAC on defrost as the AC dehumidifies the air and dry air will demist your screen a lot faster than damp air.

Nobody thinks about it until it gets hot. In the last week I've had over 20 enquires about installing AC in houses and have booked myself up fully from Friday until the 9th Aug. and there was me thinking I'd have a little part time sideline to top up the pension after I retired......

I like having the A/C in the car, if only to help in quickly reducing the condensation on the windows, but I have an under-active thyroid gland and I get cold very quickly. Consequently, I usually turn off the A/C in winter because with the A/C on the heat temperature does not get a hot as it does when the A/C is turned off.

I also find that with the A/C off, and the fans on full, the car gets warmer much quicker. I was used to working outside, often after perhaps a two or three hour car journey, and if I ran the heating on "Hot" for an hour or so then I would be warm enough to work outside, even in minus temperatures, for the morning. If I was with someone else who didn't want much heat then I would be cold all day ! Consequently, I always avoided having to travel with other people. It is just a hang-over from my truck driving days !!

Pierre3.

Richard; Please advise the RAC - as i suspect you know more than they do (or the rules changed) !

"They should also perform a vacuum test to check for any cracks or leaks that could prevent your air-con working in the future."

https://www.rac.co.uk/drive/advice/car-maintenance/air-con-regassing/

They should, not may, so they are correct. No mention of a pressure test though.....

Surely their "should" implies choice there Richard, ie. not "mandatory", otherwise they would say "must" ? .....
or is Sloth demanding we must use our A/C all the year ?!

-Seriously I suspect you are just wearing your professional hat there, I have certainly re-gassed from a can,
without breaking any rules and/or having to eat any porridge...

The RAC aren't authoritive in this matter so what they say is meaningless - along with anyone saying its normal for an automotive AC system to lose up to 20% of its charge per year... if its losing it - it is leaking. Yes flexible lines are slightly permissible to migration of the gas but it is minute.

To be fair I've not seen an automatic machine that does a pressure test - only a vacuum, which is really not good enough and that is my opinion, because a vacuum can pull small leaks closed. There may be a loophole for mobile air conditioning - I can't remember and honestly, I'm not bothered - I'm not filling anything up without a nitrogen test first. Gas costs money and is damaging to the environment.

It's also worth pointing out that the rules in other countries are very different - in the US, a gas and go even on R22 systems is the norm with known leaks. Here we can't legally fill anything that we know is leaking. So any garage with or without an automatic machine filling a mobile system with a leak knowingly is just doing so for the money.

As I said in my first post - it is not running the AC that causes the seals to dry up. And I'm not demanding anything - don't like it, don't use it - but don't be surprised when it comes to summer and it mysteriously doesn't work. I can't say I've noticed any of my cars warm the interior slower in winter because I've had it on.

As for filling from a can - there IS a loophole for things like cans of 'EZ Chill', some of which do actually contain proper refrigerant. I was surprised by that - but given how much they cost - normal punters can crack on, I'll stick to the big cylinders thanks.

davew wrote:

-Seriously I suspect you are just wearing your professional hat there, I have certainly re-gassed from a can,
without breaking any rules and/or having to eat any porridge...

You may have committed an offence but whoever sold you the can certainly did unless you showed them your C&G 7543 (Mobile AC) or 2079 (full FGas) certificate, see https://www.gov.uk/guidance/selling-f-gas-or-equipment. Halfords will sell you a can (and probably don't realise that they shouldn't) but technically they shouldn't. My local ECP want to see the certificate before they will supply R134a.

Well then perhaps you should get straight onto Halfords' case too then Richard !

https://www.halfords.com/motoring/engine-oils-and-fluids/air-con/ez-chill-auto-air-conditioning-recharge---gas-r134a-264627.html

Thank you for your allegation that I may have committed an offence. You may be wrong too !

There's a Halfords garage near me --- they do MOTs and air-conditioning --- cheaper than the kit for DIY they sell in store --- odd that ?

Is it R134 in Halfords AC charge bottles or something else that is compatible with R134 but not regulated (regulated as in should only be supplied to AC pros?

And if it's something else is it as good (efficient etc) as R134?

IIrc Sloth or someone else once said it wasn't R134 in Halfords bottles? At the time I thought there was R134 in them (thought I'd read it on the side of the bottles) but now it's been said it's technically illegal to supply R134 to none pros I wonder again if it is R134 or something else.

Like Sloth I too have never known an AC machine pressure test, only vacuum test, and have known pinprick holes seal under vacuum only for refrigerant to leak out when the system is pressurised. But then again I won't have seen as many AC machines as an AC pro.

What I have done is pressurised an AC system myself just using compressed air to check for leaks (see if the system holds pressure), I know it shouldn't be done and moisture in the air could mess up the dryer (and/or other parts?) but rather than waste an hour at Kwik Fit for an AC system to pass a vac test then leak refrigerant when I drive away (so I have to return for money back - they give a 2 week guarantee even if the system leaks) I've done this when I've suspected a pinprick hole that might seal under vacuum.

I have a few Halfords AC recharge kits, at least one intact, at least one I've cut up so I can connect an air compressor to the LP port. I wouldn't gas up an AC system from flat using a DIY kit (partly because it's cheaper to let Kwik Fit do it and the Kwik Fit guarantee) but when I have a car that takes 0.995 kg of refrigerant and I see the Kwik Fit machine only wants to put in 0.85kg of gas when my reg is entered I have to wonder if the AC system would benefit from having a bit more gas than the Kwik Fit machine puts it (even though I tell the operator to manual over-ride and set the machine to 0.995kg) because I wonder if the vehicle manufacturer knows it should really have more than 1kg of gas in it but there might be some sort of environmental threshold at 1kg - Indeed Kwik Fit charge a lot more (iIrc double their usual fee) to charge an AC system that takes more than 1kg of refrigerant. The Halfords kits come with a pressure gauge that you set according to ambient temperature, the instructions say charge with gas until the LP port is at a certain pressure when the clutch is in... but machines don't do this kind of operational test (or operators don't do the operational test) ? On a few makes/models after having an AC machine fill I've found that the AC system gets colder with the engine at idle if I put just a but more gas in it from a DIY kit... Got to wonder if the machines short-change on the weight of gas they measure they're putting in?

Years ago before AC became as popular in the UK and systems were mostly R12 if you spoke to an AC guy they'd be reluctant to regas a system without changing the dryer. Most of them didn't have machines and couldn't do a vacuum purge/test, you just parked on the street outside their house and they'd come out with a camping gaz size green bottle and connect it to the LP port... with enough pressure the AC clutch would kick in and pull the gas into the system while they watched the sight glass and filled it til there were no bubbles.

Some of the DIY things are actually R134a as it turns out - although you have to look through the MSDS datasheets to see that. A lot however are not. Probably just butane/propane mixes. As I said, there is some loophole they're working around.

Before I got my cat1 2079, the last time I had the RR filled up (back in V8 form) I went to an F1 autocentre. Got home, and while the AC was working... it was hissing - and while everyone that knows me knows I hear when things and jest about it - I damn well know when something isn't right. They knew exactly how much needed to go in, and it should not have been hissing. I knew the system wasn't leaking, because I'd already pressure tested it.

Took it back, argued with them and they did it again and gave me the machine's print out to prove how much they put into it.

What the same guy clearly didn't see is that the machine also printed out how much it recovered - 627g. Somewhat short of the 1380g factory charge.

I don't give a shit if gas is expensive if I'm paying for a flat rate service, you damn well put in what the manufacturer calls for. Would you only half fill the coolant or oil?

Yes, as in #12 Halfords sell R134a and no loopholes are involved.

R134a is chemically very similar to R134, the latter has a NBP of -19C (compared -26C for the 'a' version, thus making this more suitable for (lower pressure) car A/C purposes). The mixture you suggested Sloth could not be sold of course. it is not safe !!

Mind you when I was in Halfords buying a can of this I asked for a Torx T-25 for my P38 - but they refused to sell me one unless I showed them my C&G LR Skills Certificate first .... !!

134 vs 134a is not the point - they are both fluorinated gases and thus fall under FGas regulations.

Butane/propane mixes are not - and thus legally, anyone could wang them in. Straight dry propane can make an excellent refrigerant. Didn't say anything about it being safe, did I?

No Sloth you did not say anything about butane/propane being (un)safe - which is why I did ! The point is that R134a is the stuff legally sold at Halfords and will happily work without all the possible dangers of your mix of course.

Anyway relax, and no doubt Richard will also castigate me too in due course....

Of course, as I've just come in for some lunch. The point is that R134a is the stuff being ILLEGALLY sold by Halfords, however, I doubt anyone has ever bothered to tell Trading Standards so nobody has ever told Halfords. The trade are more concerned about the companies that will sell Chinese made, pre-charged, Multi-Split domestic AC systems to anybody even though they try to cover themselves by clearly stating that they will only supply with evidence of FGas qualification but will actually supply to anyone that asks. and before you go out and buy one to prove the point Dave, I commission tested one a couple of weeks ago and they are absolute crap......

Dave - you seem to have a habit of trying to start arguments and fuel them with random snippets from google.

I don't believe in bubble wrapping anyone and everyone that can't use a bit of common sense to work out that leaking propane into your cars interior might not be a great idea. It isn't rocket science, is is it? Come on.

I'm qualified, as is Richard, I don't personally care what others do with their time so long as I don't have to fix their mess - I don't know how Halfords get away with selling it and I don't care to delve into it further. They do, its expensive, whatever.

And before anyone says 'well in that case, how does anybody sell a fridge freezer to a customer without fgas' - the end user isn't handling the refrigerant, much like they aren't when it is operating in their car. Purchasing a can or cylinder of an fgas is intent to handle it. Unless you just want to pop it on your shelf and admire it, maybe.

Aside from that, most new domestic stuff now doesn't use an fgas. R290 (propane) is widely used in commerical small scale (maybe larger I don't know) refrigeration - you'll find a lot of catering equipment uses it. R600(a) is butane - you'll find that in a lot of domestic kitchen appliances. In both situations it is far less likely to develop a leak that could cause a fire/explosion risk as in an automotive application. Neither are fluorinated, and thus anyone can handle them or even vent them to atmosphere legally.