Avocet

Ta, interesting! My old 164 is on R12 and, of course, when that fails, I'm unlikely to get fresh supplies! The car ain't worth the cost of a "proper" conversion to 134a, so just filling it up sounds very attractive! In the course of researching it, I've been told the following by various people:

1. The R134a molecule is smaller than the R12 molecule, so the rubber hoses have to be kept as short as possible and are often teflon lined too - to minimise refrigerant loss.

2. R134A attacks steel

3. R134a is a less efficient refrigerant so has to run at higher pressures than R12 (and the condenser needs to be a bit bigger).

4. The 134a lubricating oil tends to attack the seals in an R12 system.

All of which sound at least vaguely beleiveable! I guess the other problem (as has already been said) that I'm likely to encounter is that the charging ports on my car won't couple up to the charging hoses on a 134a machine because they're a different size.

If the AC dies before the rest of the car, I might give it a go and will let everyone know what happened. I think the Environment Agency are clamping down on AC regassing companies now though, so I might not find one willing to play ball!