Automotive Air Conditioning Information Forum (Archives)

dave76 on Mon July 27, 2015 11:18 PM

Year: 1999
Make: Chevrolet
Model: Tahoe 4D
Engine Size: 5.7
Refrigerant Type: R134a
Ambient Temp: 95

Hi got some questions about my Tahoe. The compressor is belly leaking, so I plan to pull it apart and reseal it, I have the necessary tools, however do I need to pull it apart and measure the shaft to determine what size shaft seal I will need?? Also I'm confused what compressor I have, is it a HT6 or a HU6? Also the truck has C69 rear air. A/C was good but the compressor is really leaking badly now.

GM Tech on Tue July 28, 2015 8:15 AM

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Tue July 28, 2015 at 8:16 AM by GM Tech

GM Tech on Tue July 28, 2015 8:15 AM

Been there, done that- If OEM compressor (blue label), and on top of engine, and a 5.7L engine, you have an HT-6, HU-6s were all low mounted on 5.3L engines and only were on a few model years until Nippondensos took over. Your shaft will be the common shaft (smaller- same as V-5s, R-4s), the bigger shafts were in later models like 2001, 2002 model years.

I've resealed hundreds of Ht-6s, Hd-6s etc- just make sure you scribe (on the outside) of the four components- (rear head, rear cylinder, front cylinder, and front head) so that you put them back together in the proper orientation (they will go together 120, or 240 degrees off location) so that you don't create a "no pumper" situation - You only make this mistake once- because it is so frustrating to mount it back- just to take it off again and re-orient it.

Have fun...you save mega bucks this way.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

wptski on Tue July 28, 2015 8:27 AM

I marked my HR6HE but noticed that there were alignment ridges on the castings that all lined up except on the shaft end housing, IIRC.

dave76 on Tue July 28, 2015 9:47 PM

Got it on the bench disassembled, man this thing is dirty, I been cleaning all the Oring seats with a small wire brush and WD40. Before disassembly I gunked it which helped, but now I'm just wire brushing the all the cases and it looks pretty good. What oil should I use to recoat all the internals? And would it be Ok to use brake cleaner to clean off all cleaning products and the internals?

Got a question on charge, about 6 years ago I recharged with 64oz as per you guys here, however the the accumulator says Suburban 57oz and Tahoe/Yukon 44oz, the 64oz seemed to work just fine and I'm just wondering?

Also should I attemp to replace the accumulator? I did my pops Burb a few years back and had to wiz wheel the accumulator off without damaging the threads?

GM Tech on Tue July 28, 2015 10:38 PM

I don't change accumulators for failure mode of "leak" so don't change yours- I use mineral oil to lube o-rings- I don't clean the internals with any degreasers- don't want that stuff in the system- I let the old oil remain on the internal parts - why bother to clean them? They will just get oily again- as long as there is no sludge- which I never find for a belly leaker. I'd use the refrigerant charge on the label-

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

dave76 on Tue August 04, 2015 10:34 PM

Ok, I resealed the compressor, installed it, pulled a vacuum, being im in my own HVAC business I have a lot the needed tools, my vacuum pump is 6 CFM, so I left it on for an hour, shut it down and it held 30 in hg, so I charged one 12 oz can with dye, plus another 12 oz can that I had laying around, started it up, and added the remaining 32oz from my 30lb tank. Ambient was about 90, I was getting 48 to 50 degree vent temps at idle with both front and rear blowers going on high and high 30s to 40 degrees while cruising about 45 mph, I'm happy with that.