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Testing AC Components

PostPosted: 25 Oct 2011 12:20
by cv70chall
I recently acquired a condenser, evaporator and heater core and I have the opportunity to test these prior to purchasing them.
What is the best method to pressure test these parts out of the car before installing them?

Re: Testing AC Components

PostPosted: 25 Oct 2011 16:40
by Eddie
Chuck, it's not so much as a 'pressure' test as it is placing the system in a vacum. The best way to test the system is to put the components in the car, put a few ounces of PAG oil in the assembled system, put it under around 30 inches of vacum and see if it can hold this vacum for at least 20 minutes with little if any variance. The MOST important component is the compressor head, if it has failed in the past it should be either replaced or sent off to a compressor manufacturer, the reason is contamination, if it has failed it will be filled with alluminum metal shards, if it has circulated thru the system the 'shards will be in almost every component. This is why a good compressor that has a proven history or is new is prefered. The expansion valve should also be either new or a good known unit. I know this can be a pain, but testing individual components would be difficult unless you have specialised equipment and the fittings to test the components, plus assembled you can test the lines, fittings, valve, condensor ect as a system which would be hard to do indivudually. Hope this helps

Re: Testing AC Components

PostPosted: 25 Oct 2011 18:21
by cv70chall
Yes, it helps. Problem is, I would rather test the components before they're in the heater box, sealed and mounted in the car- as that's a BIG pain to get out once the dash is in. I'm trying to make sure everything's ok before sealing everything up.

Re: Testing AC Components

PostPosted: 26 Oct 2011 1:29
by Eddie
cv70chall wrote:Yes, it helps. Problem is, I would rather test the components before they're in the heater box, sealed and mounted in the car- as that's a BIG pain to get out once the dash is in. I'm trying to make sure everything's ok before sealing everything up.

I understand fully, how about taking the evaporator since it and the blend doors are the only real problematic areas that are a pain in the ass to contend with after Dash assembly, and having a local radiator shop test it for leaks and obstructions thru the core? Any good Radiator shop should be able to do this for a cheap price. If it passes muster, then assemble the A/C have it sucked down, it passes, then charge with R-12 and it should work, the only other thing would be the blend door cables, but you should be able to test those as the dash is assembled, a new orfice filter in the expansion valve and it should blast cold air in that Fla swamp! :lol:

Re: Testing AC Components

PostPosted: 26 Oct 2011 12:18
by cv70chall
Are you saying to take the entire box for testing or simply the evaporator core itself? Sure, the hoses can all be tested- we actually did a vacuum test and they're fine. I just don't want to keep opening and re-sealing the heater box, as it's a pain. I also want to test the heater core, as I will have it operational.
So far, pricing on testing all 3 was about $58. Fair?

Re: Testing AC Components

PostPosted: 26 Oct 2011 14:14
by Eddie
Yes, the evaporator/ heater core and even the condensor can all be tested to ensure there are no leaks. thats a decent price. They dont need or want the 'box' good chance they would just break it anyways.

Re: Testing AC Components

PostPosted: 26 Oct 2011 14:38
by cv70chall
I told them they were out of the box and they said no problem. I thought it was a good fair price, too. Now I have to hope these parts are good.

Re: Testing AC Components

PostPosted: 20 May 2013 16:56
by cv70chall
The cars has been home now going on a month. Finally got the trans and fuel pump replaced (Trans slipped into third and fuel pump had a small air leak)
Anyway, we had charged the AC system up 3 months ago- I had the major components checked and they all came back OK. System held for well over 2 months.
When I drove home- I got maybe 2 days out of it and poof. We re-charged it yesterday and same thing-
I'm going to get some dye to run thru and see where the leak might be (it obviously has one) and go from there.
If it's in the heater box, how easy is this thing going to be to get out and back in?
How critical is it to have the heater box sealed tight? Is it more so that water can't leak into the car or to prevent freon from leaking out?
-More and more teething crud...
Thanks