AC leak

[vandenham]

An AC shop tried to recharge my air conditioning, but there was a leak somewhere in the system and you could actually hear it hissing. The technician thought it was the line from the condenser going back to the expansion valve at the firewall.

So I took off the offending line and took it back to the AC shop and they said they pressure tested it and there was no leak. Before I go and start taking other lines off for testing, I have a question.

This is the line:



The line consists of a short pipe that attaches to the condenser, a rubber hose section and finally a long brass pipe that attaches to the expansion valve.

The rubber section can be rotated slightly where it is attached to the brass pipe as seen below:




I thought this was where the leak is, but the person who tested it said these are designed so they can rotate to help with assembly. My thought is that if it can rotate, it must leak as I cannot see how it could seal if it is movable.

Do anyone here know if this connection can be rotated or must be fixed?

It is quite a lot of work to remove these lines from the car and I don't want to take more stuff apart if this still might be my AC leak problem.

Thanks,
Rick

[19psi]

Any competent shop should have had an electronic leak detector and pinpointed the "hissing" leak within minutes. If you were local I'd do it for you.

I believe that fitting should be crimped tight, I've never seen an A/C hose that can swivel. I also doubt the technician had any type of fittings to attach to that hose and properly pressurize it.

[vandenham]

Thanks George - can the existing hose be crimped further to resolve any leak (I suspect not) or should I just have the hose portion replaced?

Even if this is not my leak problem, I think I should have it repaired/replaced to eliminate this line as a potential problem.

Rick

[76FJ55]

The line shouldn't swivel, and yes, I would suggest replacing the flexible section before re-installation. Even if the line is still sealed the old line is still mode porous than the new barrier hose, so it is a forth while change especially if you are converting to 134a as the 134a molecules are smaller than the 12 molecule that that hose was originally designed for, and will bleed out faster.

[vandenham]

Great - now I know what to do and can't wait to have cold air blowing!

Rick

[stepson]

But remember: the same guy that told you the line was designed to rotate is the guy that told you it might be leaking! Put it back together and have a competent shop use a sniffer to pinpoint the leak in lieu of spending unnecessary money.

[vandenham]

John - your point is well taken. Actually, it was the technician that told me which line it was, but it was the front counter service guy that said it was designed to rotate. I still should get the flexible section replaced before I find a shop that can do a sniffer test.

[MPDano]

Too bad you don't live in East County San Diego, I have a great hook up on a very competant AC Shop near me. Both my 928's have ice cold AC since I brought it to them. George is totally right, any competant shop should have given you the exact spot it was leaking, plus they can add a dye to proof that.

[vandenham]

Good news - I had the hose section replaced and put the AC system back together with a new dryer. Then I had the AC shop charge the system with 134a. It now blows ice cold.

Not so good news - when they pressured up the system with nitrogen (to 250 psi), there was a small drop in pressure over time, so it appears there is some leakage somewhere in the system. There is dye in the system now so after a week or so, I should be able to do some black light testing to see if I can spot a leak.

In the meantime, I am enjoying it being cool inside.

Rick

[MPDano]

Bummer, most competent AC Shops have a Sniffer. That would pinpoint exactly where the leak is immediately without waiting for the dye to appear.

[vandenham]

I am hopeful that the leak is very small or it corrects itself once the lubricant gets around the system, but I will finish cleaning up the compressor and lines so any dye will be easier to see.

Has anyone tried the Red Tek ProSeal or LeakStop to fix minor leaks - I suspect my leak may be at some of the older seals that I did not replace. The AC system was not working when I bought the car 3 years ago and I don't know how long it was dead before that.

[JK McDonald]

Hey Vandenham, Although I have heard that some of the A/C system sealing formulas and products do work - many have disclaimers attached on the long term results of their use. Among the list of precautionary warnings that always concerned me were - 1) No liability or guarantee is being made or implied by the manufacturer 2) This compound will not repair a leaking clutch shaft seal and 3) This sealant may result in the contamination to any Freon recovery equipment and/or storage containers during any future repair or service.

I have always found that it is usually best in the long run to simply find and repair the leak. The red dye you have added will help zero in on the malfunctioning component. One more thought - Don’t forget to look behind the clutch/pulley assembly on the compressor for evidence of a leaking shaft seal. Although on older compressors this is sometimes the culprit - it can be easily replaced once the clutch is pulled.

Good Luck, Michael

[vandenham]

Thanks Michael - my first goal is to find the leak using the red dye. Once I find it, I plan to repair it, but was wondering is these sealing products would work if it ends up being a really small leak.