Air Con re-gas. How to get a reliable pressure test to see if it is worthwhile?

Undervalued

Hi I have an ancient (18 year old) car.

After about 12 years the Air Con stopped working. Passed a vacuum pressure test so was re-gassed. Worked for about three years.

Repeat, different garage, same story but lasted barely two years and maybe not as cold as it used to be.

Third attempt, different garage. Told them the story and impressed on them that it was only to be done if worthwhile. "Yes mate, vacuum test perfect - see the printout". Lasted barely six months!

Is a vacuum test actually useful? Surely it pulls the seals the wrong way and is testing the opposite of what is needed? Is there an alternative?

Any views on where I go from here?

Thanks. 

Herzlos

Take it back to the last garage to do it and explain that it's only lasted 6 months and get them to investigate. It's possible something has failed that won't have shown up in a vacuum test.

The first step is usually to re-gass it and see what happens. I think they use coloured gas to make it easier to spot leaks.

Mr.Generous

This should be really obvious but I'd overlooked it myself ....

I do my own car servicing, pollen (cabin) filter due for a swap every 2 years or 20,000 miles. Having done not many miles with lockdown etc I just vac'd it at the 2 yr service - it looked brand new almost. At thge 4 yr service I was running short of time so I left it to do a few days later ...

Almost a year on, the aircon was weak and not very cold, cabin airflow poor ... (yeah I know, its obvious!!)

But I did the pollen filter, and hey presto, air flow much improved, air con icy cold again, gets colder quicker.

If you don't know for certain your pollen filter has been swapped give it a go. And don't assume any garage service would have done it, they don't always, even when it's on the schedule. They usually try and charge extra to do it.

If its not been changed / cleaned at all expect it to be blocked with dead leaves too!!

Undervalued

Herzlos said:

Take it back to the last garage to do it and explain that it's only lasted 6 months and get them to investigate. It's possible something has failed that won't have shown up in a vacuum test.

The first step is usually to re-gass it and see what happens. I think they use coloured gas to make it easier to spot leaks.

Unfortunately I let too long go by due to Covid lockdowns and lack of use.

Undervalued

Mr.Generous said:

This should be really obvious but I'd overlooked it myself ....

I do my own car servicing, pollen (cabin) filter due for a swap every 2 years or 20,000 miles. Having done not many miles with lockdown etc I just vac'd it at the 2 yr service - it looked brand new almost. At thge 4 yr service I was running short of time so I left it to do a few days later ...

Almost a year on, the aircon was weak and not very cold, cabin airflow poor ... (yeah I know, its obvious!!)

But I did the pollen filter, and hey presto, air flow much improved, air con icy cold again, gets colder quicker.

If you don't know for certain your pollen filter has been swapped give it a go. And don't assume any garage service would have done it, they don't always, even when it's on the schedule. They usually try and charge extra to do it.

If its not been changed / cleaned at all expect it to be blocked with dead leaves too!!

Thanks but pollen filter has been changed regularly.

The air con is not cutting in at all, due to the low gas pressure sensor. I do wonder if the last lot just put enough gas in to get it to work rather than filling it to capacity?