aircon service

[pablo]

Yep, I know that vxcalais, but I think a lot of posters here don't own or, if they do, don't bother to look in a work shop manual!

Pablo

 

[Mudguts]

I am an ex refrigeration mech, and I can tell you that the only things they will look at during a "a/c service" is the gas level, the cleanliness of the condensor at the front of your car, and maybe if they are really keen they will blow out the evaporator box/make sure drain area is clean.
The winter/low temp problem can be solved by simply bypassing the thermostat electrically.

A good a/c system that is looked after by running once a week "should" hold its charge for the life of it.
Typically this is rarely the case because of the amount of rubber hose used in the system that eventually becomes porus and leaks out slowly when not in use.
A system does not "use up" gas.
When it eventually ends up with a leak, every effort should be made to actually find and repair it......rather than just "top it up". I would think about replacing rubber hoses etc while the system is down after more than about ten years or so. That will lessen the likelyhood of another trip to the repairer the following year.
You need to be licenced to buy refrigerant (and to use it), so it is not a DIY job to repair one.

 

[pablo]

Good call Mudguts!

 

[nathans1987]

I recently had mine re-gassed; I was told by the bloke realistically, depending on the state of the air-con compressor, a re-gas should last you 12 months.

So realistically, if there are 3-4 months of need for air-con use, the re-gas should last you 3-4 years. So I was told. Sounds realistic to me. Cost me $120 for the re-gas and an additional $100 to replace the TX valve (??? i think that's what it's called).

A new compressor could cost you up to $300 (depending on whether you get a new or refurbished unit). Hope that helps.

u dont use air cond in the winter?? mine is on all the time to stop foggin up windows.

 

[commsirac]

The winter/low temp problem can be solved by simply bypassing the thermostat electrically.

And how does one test that it is performing to specifications in cold temps? Even a system with serious shortcomings can appear great with 10C ambients.

Even if you can trip/trick the compressor to stay on, the evaporator will freeze over fairly quickly, what would you test for :vent temps of -10C with an ambient of 10C? and get your readings before the air stops blowing? Does holden provide some temp charts for use here and likely high and lowside pressures?

Really, unless one can simulate high ambient and interior temps, testing the performance of condensor and evaporator is guess work.

Of course if the system is known to be in good working order, evacuated and then the correct amount of gas is weighed and added, then all should be fine.

 

[bezz]

With my last 2 commodores, the a/c problems have always been attributed to a dodgy tx valve. I'm pretty sure both times the tx valve went I had to have the a/c regassed aswell. Apart from those 2 times, I've never needed to regas or 'service' my a/c.

Amazingly for once i actually agree with commsirac aswell about testing the a/c

 

[commsirac]

I'm pretty sure both times the tx valve went I had to have the a/c regassed aswell.

Yes, even if the system had not lost any gas, it would be impossible to remove the tx valve without losing all the gas, so it would have been evacuated first and regassed after the repair.

 

[Mudguts]

Hi Commsirac
There is no "testing of evaporator or condensor efficiency" or anything that technical.
If the gas level in the sight glass is right, and the air is coming out cold...........service is complete!!!!!

These guys are motor mechanics, not refrigeration mechanics. That type of work is only done when there is a problem that is not obvious to the naked eye, or in the design phase of the system. If you think that that happens during a "service", then you will be sadly disappointed.

 

[commsirac]

Hi Commsirac
There is no "testing of evaporator or condensor efficiency" or anything that technical.
If the gas level in the sight glass is right, and the air is coming out cold...........service is complete!!!!!
.

Exactly, thats why you should only take it to them when conditions are hot, if the air doesnt come out cold then the service is not complete and then they have to start scratching their heads on what is not right. Yes, and I take your point on motor mechanics and air con servicing. I havent found places that supposedly specialise in aircon much better either.

Whatever it takes to get one's r134a licence is not really enough to completely understand how all the systems work and be competent at fault finding and solutions.
I know all this from first hand experience and hence the reason Ive researched/learnt how to do my own ac work.

 

[BowTieGQ]

Mudguts is on the ball, you all should listen to him. I have been in the automotive repair game for many years and while I know a bit about ac, I always chat to the ac guys and ask heaps of questions. I also believe it is illegal to regas a system if the ac guy suspects that it will leak. He can be fined heaps. So the way I interpret this is, any vehicle presented to a mechanic (first mistake) that has a ac unit low on gas (hopefully the mechanic can spot this in 1 minute and send you on your way to an expert) should know that it has leaked out and therefore should not be regassing let alone topping up (there's another falicy) system until rectified. EPA regulations I believe. Top ups are ridiculous as the system needs an accurate amount of gas to work efficiently. It is measured in grams and therefore you wouldn't know how much to top up as you wont know how much is already in there. Servicing ac is a scam. The only things possible are visual inspections and maybe the belt on compressor. It is also very common for Commodores to lose their gas due to the poor manifold design on top of the compressor. It only has one bolt to hold it with pressure on either side of it causing it do bend very slightly and leak. But even that needs scavenging of the old gas, new o rings and a full regas. Sorry for long rant, just sick of this ac service scam.