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Leaking Rear Air Line - Repair or Replace?

TominKY on Sun July 20, 2008 11:39 PM User is offline

Year: 1997
Make: GMC
Model: Suburban
Engine Size: 5.7
Refrigerant Type: 134a
Ambient Temp: 91
Pressure Low: 40
Pressure High: 215

I have posted a couple of times about my 97 Suburban. Problems started with a pinhole leak in the high pressure line leading to the rear evaporator. This line is aluminum, and it had some slight corrosion where GM had placed a rubber sleeve to protect against abrasion. I removed the line and had it TIG welded. Now, after a recharge, it is leaking again, from another pinhole about an inch away from the original defect.

Has anyone had any luck repairing these lines? I had the low side line repaired with a section crimped in several years ago, and it is holding well, but the high side deals with much higher pressures. Is it worth another try to TIG it again, or best to bite the bullet and fork out $174 for a new line?

Thanks for the help!

Tom

Edited: Mon July 21, 2008 at 6:52 AM by TominKY

TRB on Mon July 21, 2008 3:24 PM User is offlineView users profile

Sometimes it's best just to replace those lines. You weld one area and another leaks shows up. If you just have the one leak, instead of welding you might try the in-line filter as a splice.

In-line Filter

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webbch on Mon July 21, 2008 4:10 PM User is offlineView users profile

Is barrier hose with crimped fittings not good for the high side lines then?

mk378 on Mon July 21, 2008 4:16 PM User is offline

You could remove the line from the SUV, cut out the sketchy area and fabricate a section from new metal tubing to replace it, and weld it in. If you want to go to rubber and back you'd have to weld hose barbs on anyway so it's the same work either way.

TominKY on Mon July 21, 2008 5:39 PM User is offline

I took it back to the welding shop, and they zyglowed the whole thing. Welded up the area of the leak and a couple of other questionable areas. I saw one other area with some very light pitting - I am going to wire brush it real good and hit it with some JB Weld for assurance. The area of the leak is in a curved section, so an inline filter is not a real good option. I considered splicing in a new section, but that would require putting all of the bends into the new section - might be tricky. I am going to try it again after the rework - if it leaks again, I guess that is a signal to spring for a new line.

Why do they insist on making a line that goes under a vehicle where it can be exposed to road salt out of aluminum? Is there some reason they don't use stainless steel on lines like this? Does stainless react to the refrigerant?

webbch on Mon July 21, 2008 6:29 PM User is offlineView users profile

Be happy it's made out of aluminum, and not regular steel tubing. My 97 town & country minivan has rear coolant lines out of steel, and a common problem on these vans is having them rust out over time. Doesn't help that it's a major job to replace them either. Many just cut off the steel tubing and replace with rubber hose and hose clamps (obviously not an option in your case). The aluminum lines to and from the rear evaporator do not seem to be nearly as prone to problems.

I would guess stainless is more expensive as the reason it's not used.

Chad

TominKY on Wed July 23, 2008 11:04 AM User is offline

Just to wrap this up - we gave it another try with the TIG welding. This time he hit just about every spot that looked questionable. There were a couple of other areas with slight pitting, so I wire brushed them real good and applied some JB Weld over them for good measure. Reinstalled the line, vacuumed it down and recharged. So far so good - no evidence of leaks.

Of course, while I was down there checking the refrigerant lines I thin I may have spotted the beginnings of a leak from the antifreeze lines leading to the rear heater core! I just LOVE these rear HVAC systems!

Thanks for all the help! This is a great site, and I intend to support it with a small donation.

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