Rover 600 air con not working

In news: snipped-for-privacy@q75g2000hsh.googlegroups.com, snipped-for-privacy@gmail.com wittered on forthwith;

Nope.

Lack of gas probably. People will insist on only using AC on warm days, then they wonder why in the UK the AC only works occasionally.

Here's a clue, the gas lubricates the seals in the compressor etc, if you use your AC for 5-10 minutes a week, regardless of weather, you'll have AC that works in the summer.

Thanks for prompt reply.Car has been kaid up since xmas and only donr

500miles since MOT in September. Guess i will get a regas as it will get used extensively over summer

Just to be pedantic. It's not the gas that lubricates the seals. That is done by oil that is added to the gas when the a/c system is filled, which is why it's preferable for the OP to have the system checked, then purged and refilled with the correct proportion of both, if no obvious leaks are found.

if you

Good advice. The reason why the a/c in my SD1 no longer works, after being left unrun in a garage for a good few months. :-(

A useful tip for those with pre '92-'93 cars with a/c using R12 gas. R134A can be used cars that have R12 a/c systems as long as they are filled to the same pressure as an R12 system runs at, and also that the added oil is the correct spec for an R12 system. The oil normally used in R134A systems is incompatible with the seals in an R12 system. Probably why many think R134A can't be used, apart from the fact that the later system runs at a much higher pressure. Mike.

you don't mention the flushing of the system, the replacement rubber hoses and seals, new dryer, system connections etc. etc when converting, nor the fact that r12 condenser size is usually inadequate, or that 134 is not as good at cooling as r12. If you can, stick to R12, it is far better.

or that r12 oil is not picked up and taken round by 134, so your system won't last either.

If by flushing you mean somehow washing out the system, it's not necessary. Simple purging should remove the R12, most oil, and any moisture, and that is all that's needed.

the replacement rubber hoses

Neither is it necessary to replace the seals and hoses. The gas itself is not a problem for R12 hoses and seals. What they can't cope with is the higher pressures and the oil that is normally used with R134A, but as the pressure and oil is the same as that for R12, there is no problem.

nor the

My old Celica GT4, sold to a friend, had it's R12 system filled with R134A over 6 months ago, in exactly the way described. I also know of other R12 systems that were filled with R134A over 2 years ago, that are still working well. Maybe it's not as efficient, but you'd need a before and after temperature reading to prove it.

The last few days in the south have been quite warm, yet the GT4 a/c could still blow ice cold air. Based on that performance, I have little doubt that even with ambient temperatures in the low 30's, it will easily keep the interior of the car at a comfortable temperature AFAIC that's the only criteria that really matters with an a/c system.

If you can, stick to R12, it is far better.

AFAIK It is now illegal for a/c Co's to use R12. They can remove, and dispose of it. But what they can't do is reuse it. Apart from that, the units used for purging, refilling etc of R134A systems, can't be used with R12, and that's not just because the fittings are different.

I have seen all the proof I need that the method works, and not just over the short term. I get the impression that you are repeating what the 'experts' say. Don't believe them. They are wrong. Apart from that, there is nothing to lose by trying it for yourself, apart from possibly the cost of the regas etc, which shouldn't happen unless the system is knackered anyway. Mike.

Do you know that for a fact? Because over 2 years without any problems would appear to refute that suggestion. Mike.

vacuum will not suck up compressor oil (hence need to flush). 134 and r12 oil do not mix (according to the suppliers)

That's right, and R12 seals are not compatible with 134 oil as well, but if you refer to my original post you'll see that 134 oil is not used with the

134 gas. You must have missed that bit in my earlier post.

The 134 gas is not supplied premixed with 134 oil. The oil is added separately. Just means adding R12 oil instead of 134 oil. This also means the old oil doesn't need to be flushed completely from the system, and any R12 oil remaining after purging is not a problem. Mike.

I meant that 134 gas turns r12 oil into cottage cheese, it is not compatible, which is why you need to flush out the whole system and clean the compressor, maximum left of r12 oil is less than 1 percent of original quantity, so only a cc or so in the whole system is permissible (this is also why you change the dryer.)

Where does your information come from? You're telling me it doesn't or can't work, when I know from practical experience that it can and does. If what you're saying is true, how do you explain how two R12 systems, filled in the suggested way, can still be running satisfactorily. One after

2 years, and another, owned by a friend, after 6 months? Either what you say is untrue, or the systems are quite happy to be lubricated by oil with the consistency of cottage cheese. :-) I know which alternative I believe is true.

I don't know what is happening inside the systems, but I would guess that the only reason why 134 systems use a different oil, is because they run at a higher pressure, which could mean the seals are made of a different material, and or design, which calls for a specific oil. An oil which is incompatible with R12 seal material. Mike.

In news:46226dfb$0$8724$ snipped-for-privacy@ptn-nntp-reader02.plus.net, Mike G wittered on forthwith;

My understanding of the R12 / R134a issue is that the seals for an R12 system aren't that gas-tight as the seals for an R134a system. R134a will normally escape from an R12 system for this reason and because R134a molecules are smaller than R12 ones or something. I'm not a chemist or any good at chemistry - I'm just a bloke who's done a very minor AC course and this is what I was told.

I was also told the R12 systems normally use mineral oil, R134a systems use a synthetic oil and that the two don't mix. However, from my experience all that happens is the oil will just degrade to the quality of the less good oil so in reality it's probably not a major issue.

There is a replacement for R12 on the market which is a direct "drop in" gas, I think it's called R24 or R42. Can't remember.

134 gas has a smaller molecule size and can leak through holes r12 won't go through. as long as the orings are synthetic (usually green) they are ok 134 runs at a higher pressure than r12 (this can overload the compressor) r12 driers use a different substance to dry than 134 needs R12 hoses may leak with 134 mineral oil is fine with 12, not carried by 134 ester oil is ok with both gases pag oil should not be used in r12 systems at all 134 may need a larger condenser to get the same cooling effect.

I am very pleased to hear that the systems you know of still work OK, from my experience you have been lucky, I do not know of any other bodged R12 systems that still work OK.

Mrcheerful

"Pete M" wrote in message news:evtroa$54o$ snipped-for-privacy@registered.motzarella.org...

After R12, Freeze 12 is the best replacement, RS24 or Isceon 49 are other good ones, none seem as good as R12 though, and they need different refilling methods to standard as they are blends.

In news:bBuUh.24810$ snipped-for-privacy@fe2.news.blueyonder.co.uk, MrCheerful wittered on forthwith;

That's the one RS24. Ta.

That, I know.

I don't believe that. 'O' rings and lip seals etc, are made from a variety of synthetics. Nitrile, Silicone. PTFE, Viton, Vamac etc etc. Different materials for different applications and environments. I think the material chosen for R12 or 134 seals will be the one that best suits the criteria required by the particular a/c system.

You don't appear to have read my OP. The compressor is not overloaded because the system is only filled with R134A gas at the same pressure as an R12 system.

But you don't appear to have had any personal experience of what I'm suggesting. I suggest you try it, before theorising that it not a cheap practical way of getting an R12 system working without using R12 gas, or having the system fully converted to using 134.

As I intimated, I only know of two systems personally, but the a/c guy that did both of those has done quite a few others, as he's been doing the same conversions for over 3 years now. From what he tells me the conversions give no more trouble than any other a/c system.

Those sort of results can't be just due to luck. It obviously means that the conversions work.

Seems you haven't quite understood my explaination. I've no doubt that an R12 system filled to the same pressure as an R134A system will probably leak and give trouble. In effect what I'm saying is that the R12 system is gassed exactly as one would if it were being regassed with R12 gas. Same oil. Same gas pressure. The only difference is that 134 gas is used instead of R12. Mike.

134 needs a higher operating pressure to get the same discharge temperature, it is nothing to do with the charge pressure. Air con is usually charged with a certain weight of gas (a retrofit with 134 would use aprox. 80 per cent of the gas weight of R12)

Mrcheerful

You still seem reluctant to say where your information comes from. To sum up it seems that you don'y believe it can work. At least not for very long. Whereas from personal experience I know it does work. I've seen the proof. A system still working after 2 years is enough to convince me. Mike.

a few years ago I tried doing some refilling of granada R12 systems, even if they worked at first (not all) they didn't a few months on. I concede that since then I have not bothered and I may have had some knackered systems to start with, but all the info I have since read says the same thing: Do it right or don't bother.

I repeat I am glad that someone has managed it, if I had something borderline R12 (all working but down on gas) come in now, I might try it again, but mostly I only see stuff with 134 in now.

Mrcheerful