Sick air con improving

That might be a popular opinion, but I feel it might have more to do with what a/c engineers would like us to believe, rather than one based on hard evidence. A/c engineers have got to get there money from somewhere.

My first car with a/c, I bought in February 1988. I had it regassed at that time after repairing a leak in the condenser. The a/c was still working in

2002. During that time it hadn't had any maintenance. That's 14 years. IMO it only stopped working because the car was left garaged for a few months, without being used. I baught another car in 2002 with a/c.The a/c was working when I bought it, and was working today. The last time it was run was in February. That's 4 years give or take a month or two. My daily car I bought in January 2003. I have no idea when it was last regassed, but it seems as efficient today as it was when I got it.

You say refilling every 3 years makes them last longer. Longer in what way? I can't see it reducing wear on the compressor, which is the only part subject to wear, so I don't see what is to be gained by regassing at regular intervals. Why spend money on it, if it aint broke? Based on my experience, I would suggest regassing when needed, will work out cheaper than regassing every 3 years.

Snag is it'll

Let me know when you have a definitive answer. :-) Mike.

Well no, not really. Different systems (cycling clutch, orifice tube, expansion valve etc etc) will give different LP readings, and ambient temperature makes a big difference to pressures also. You always balance L & H pressures against ambient and vent temp to establish a correct charge in the abscence of a sticker.

The halfords can/gauge effort is extremely crude to the point of being dangerous.

I serviced a City Rover (well quite!) with non working a/c the other week, where the owner insisted that it couldnt be low on gas, as a 'friend' had topped it up with a 'halfords aerosol and that didnt work'. Static pressures were somewhere near normal at 75psi, but discharing it, I found nearly 2 kilos of R134a, where there should have been only 900grams. The 'friend' must have emptied at least a whole can into it in the hope that it would start going, and the pressure gauge was still showing 'normal' figures.

The acutal problem was the connector had come off the HP switch. I would have expected a burst compressor if it had actually tried to run with such an overcharge.

Tim.

The £17 kit doesn't include a gauge. There's a more expensive one that does.

Problem is that as the gas leaks (which they all do, (there is no choice, given rotating seals and rubber piping, plus orings and connectors) the gas takes out with it some of the oil, eventually enough oil may go to cause the compressor to fail, once that has failed you have a load of crap in the system and the repairs are super dear.

mrcheerful

You might be right, but I don't think so. The argument makes the assumption that the oil leaks out with the gas. I would suggest that that is not necessarily the case.As it would depend on the molecular size of the oil particles as compared to those of the gas. If the gas molecules were the smaller, most of the oil would remain in the system. It also makes the assumption that the compressor will continue to run if the level of gas and oil were too low to adequately lubricate the compressor. IMO before that point was reached, the lower pressure would trigger the low pressure switch and the compressor would be switched off. Thus preventing any permanent damage. All theoretical of course, but until someone can show where my theory falls down, I'll continue to believe that maintenance is a waste of money. Mike.

What i meant was that if you over-fill an AC system it becomes less efficient - it requires a phase-change to occur in its coolant and this cant occur to any great extent, if at all, if its over-pressurised/filled. Hence a slow leak would bring it back to an efficient range, for a bit. Its just my best guess TBH. If it were mine I'd leave it a bit longer and see if it keeps improving. Bear in mind that its getting cooler now so it will be more efficient again than when it was hot weather.

And as well as the oil coming out water goes in, you can see it if you look at the stuff that gets vacuumed out.