A/C - replacing compressor, condenser and dryer

[hj60]

Originally Posted by archie

I think I have an AC leak and noticed flourescent green dye on my Low valve and cover when I opened it. I looked with a black light all over the place for other leaks but with no luck in finding the leak. I think this valve is the source of my leak and wonder how do I repair it. Any suggestion? Thanks in advance.

You can buy just the valve core at most auto parts stores.
I keep a couple in my toolbox. Sometimes they just come loose. They're like a large tire valve core. A parts store should have the tool for it, too.
On our domestic trucks, we automatically replace the high and low service ports/valves if it's been more than a year since the AC was worked on.
I got tired of charging a system up, having it freeze out the driver and pass all leak tests, only to come back a week later not working.

Had one S-10 where even after I replaced the valves, it still leaked down in a week or so. After nearly pulling my hair out and putting my tools on Ebay, my boss discovered that the cap was depressing the valve just enough to allow a slow leak. We laughed for an hour straight at how many hours we had both put into that thing.

[archie]

Thanks for the reply! Is it neccesary to vacuum the system if the valve is changed?

[flintknapper]

Originally Posted by rhyary

Well, you guys are going to be proud of your protégé'
I cancelled the order at HF, and bought from NAPA 3cfm vacuum pump and manifold gauge. It was expensive! But I rather have the stuff then paying for the service.

Once I figured how everything connects and saw all about this vacuum pump first hand, I decided that I should do as advised. Besides after resting from the 6 hours job of replacing the components, just opening the lines in the firewall did not seem to be a big deal after all.

So I went for it. I opened the lines and flushed the system. From the big hole (low side) to the high side. All that came out was very clean. Replaced O-rings with new and closed the lines.

I ran the vacuum for about 10 minutes, and stopped to see if it holds vacuum. After 10 minutes it still held the vacuum at -30. So I turned on the pump and ran it for a long time. Close to 60 minutes.

While the vacuum was running, I finally got around to drilling the right corner of the ARB for the CP antenna. Came out great!

Back to A/C. after running it for a long time I turned it off and waited. Vacuum still on -30 and holding. Good.

Ok, took the M5 for its unusual task, doing errands. I normally use only the LX450 for errands. Bought 4 ounces of oil (2 cans of 2oz) and 3 cans of 134a.

Put the oil in, put the 134a in. After two cans still bubbles in the eye sight. Put another can in. Check gauges. No bubbles. Gauges good.

A/C blowing popsicles.

Drove in first around the block to see if I get any noises from the A/C compressor at 3K or 4K rpm. Nope. Quite.

Now I only hope that I don’t have leaks. And I am good to go.

Atta Boy! Proud of ya.

[Scamper]

Originally Posted by archie

Thanks for the reply! Is it neccesary to vacuum the system if the valve is changed?

Can't change the valve without loosing the refrigerant and allowing air into the system, so yes. Pulling a vacuum removes the air and the moisture (which is the biggest problem) as well.

[TX_TLC]

Originally Posted by flintknapper

Atta Boy! Proud of ya.

Flint- I just sent you an email.


Thanks

[flintknapper]

Originally Posted by Scamper

Can't change the valve without loosing the refrigerant and allowing air into the system, so yes. Pulling a vacuum removes the air and the moisture (which is the biggest problem) as well.

Actually, there is a tool that will allow you to remove and install a shrader valve will minimal leakage.

Mastercool 91490 Standard Valve Core Remover / Installer

Probably not worth buying unless you do this kind of thing regularly.

[TX Cruiser]

Great job man!

GM vehicles are the worst at leaking from the fittings. I had one this week, the other shop who sent it to us said it would leak out over night. Sure as shit the high side would let it loose when the pressures got low enough. Those valves are junk.