R1234yf and R134a air-con canister fitting.

WIAWSNB

Hi.

I understand the difference between the two types of gas, and my current car uses the more recent R1234yf. I have topped up my previous R134a car successfully using a kit, so understand the process. 

My current car had a full air-con gas replacement a couple of years back, at a reasonable £50 or so, but the same task now comes in at over £120 - and it needs doing again. So, time to DIY and buy a can and hose of the new stuff.

This should be easy. The R134a cans had a 1/2" ACME RH - conventional - thread. The new cans are seemingly 'supposed' to have a LH thread, but many don't. I know the car ends are different - that ain't the issue.

Also, the newer cans should have resealing outlets, but - again - many do not; they are 'puncture' type. What the hell?

Could anyone clarify, please? What should it be?!

Ta.

facade

I looked into this and spotted that the cans are R1234yf EQUIVALENT, which immediately put me off.

If you search around you can find places that charge by the gram of additional gas required rather than a £120 fixed fee. As the system gives up when it is down to 50%, and it has just given out you can assume there is 40-50% of the gas left so you can figure out if it will be cheaper to use this route.

The cheap adaptors all seem to be a piercer valve for a single use can, you screw it down to stop the flow, and hope the gas doesn't escape, but tbh it would be best to just write off the can as it will likely have escaped by next year.

I just paid through the nose for a re-gas. After 2 years I was down 30%. Previously it was on the verge of giving  up after 4 years and needed over 50% to get it back working- I forget exactly how much.

By co-incidence my youtube clickbait list has recently filled with videos of people claiming that you can cause the car to explode/run up a bill of thousands/kill yourself/demolish your street/make the cows stop giving milk and the hens stop laying if you do a DIY topup!

(Basically by ignoring any form of common sense and just forcing the whole of a jumbo can into an already working system. (Yes I clicked.....) One guy knew full well his cheap gauge wasn't working and carried on adding the whole can anyway, even though he had 9 degree air coming out the vents with an ambient in the mid twenties before he started, then "panicked" when the engine started labouring trying to circulate completely liquid coolant at about 500psi on the low side.....)

QrizB

facade said:

I looked into this and spotted that the cans are R1234yf EQUIVALENT, which immediately put me off.

Looking at eg.

https://www.ebay.co.uk/itm/316666190841

... it seems the replacement gas is a blend of butane and propane? That makes a sort of sense since I think R1234yf is a F-gas and can't be sold to the public? It's listed here:

https://www.gov.uk/guidance/fluorinated-gases-f-gases

I'm reminded of my old R12-equipped banger which had a leaky AC system and needed topping up every couple of months. I enjoyed cold aircon for 3 or 4 summers thanks to a 13kg Calor propane bottle and about £15 in hose & pipe fittings.