Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

1998 Suburban AC

alchemist_bobtilton on Sat August 11, 2007 9:07 AM User is offline

Year: 1998
Make: Chevy
Model: Suburban
Engine Size: 5.7L
Refrigerant Type: 134a
Country of Origin: United States

I have a 98 Suburban w/rear AC and heat. Just bought from someone used. Has 215K miles. I just charged the AC unit, and it cooled fine (cools better when rear AC is on for some reason, but that's another issue), for two days. The unit leaks down fast at the compressor (oil observed using UV dye, etc.). I'm going to do a complete replacement of compressor, o-tube, and accumulator. Also plan on doing flush. Anything else to be aware of - I've never worked on one of these dual units. Does it have two orifice tubes (i don't think so). Can you flush the lines that have the filters (e.g. ones going to and from compressor)?

Sorry for so many questions - this AC system is a little different than the 96 Caprice that I generally work on.

mk378 on Sat August 11, 2007 10:28 AM User is offline

The rear evaporator has a TXV, which will have to be disconnected to flush that evaporator. For most problems, think of these systems the same as a front-only CCOT system. Especially while the rear fan is off, the TXV should close fully then the rear evaporator doesn't affect performance any. Of course the oil and refrigerant specified amounts will be more with the rear unit, so make sure you're using the right specs.

alchemist_bobtilton on Sat August 11, 2007 2:37 PM User is offline

Does the TXV have to be replaced, typically? What would cause my unit to blow colder air when the rear AC AND the front is on, versus just the front? Last question - where's the TXV for the rear? Presume inside the rear of the vehicle, where it looks like the lines enter? Is it a biotch to remove?

GM Tech on Sat August 11, 2007 5:21 PM User is offline

why would you flush for a leaky compressor? I only do it for a contaminated system...............

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......

JACK ADAMS on Sat August 11, 2007 6:26 PM User is offline

We always flush with a new compressor as well as changing the accumulator and Orifice Tube. The Suburban has a TXV in the rear Passenger side fender well, you will need to soak these fitting real good prior to removing. Best place to start is to remove the front Orifice Tube and see what you are in store for! The Orifice Tube will be located next to the battery on the left front fender; you will see a “Y” type connection; this is where it will be located on your application. The HT6 compressor is notorious for leaking around the case seals and also for Black Death. Hope this helps and good luck!

mike. on Sat August 11, 2007 11:10 PM User is offline

don't bother taking those lines underneath 215,00 miles they aren't gonna come off easy....i tried with mine that only had 200k and i gave up and just cut the hole...theres a tsb about changing the txv by cutting holes in the evap case....i did this to mine and it was very easy...i would definitly change it though....

i heated a razor blade to cut it so i didn't risk cutting the ac lines

and like gmtech says...if its not contaminated there isn't any reason to flush...since you cant flush the mufflers on the compressor lines and i believe that the condenser is a parallel flow but i could be wrong on that one..which can not be effectivly flushed

alchemist_bobtilton on Sun August 12, 2007 12:37 AM User is offline

why would you flush for a leaky compressor? I only do it for a contaminated system...............

By contaminated system, you'd mean one that had compressor valve guts spew into the lines? My charge does pretty much go down (e.g. no more freon) in a few days, maybe a week. Yes, the compressor is leaking at the case seals.

Chick on Sun August 12, 2007 6:23 AM User is offlineView users profile

Leaky HT6 compressors are very common. I strongly suggest using one of the "clones" when you change it. I used the Valeo (Seltec) on my own 97 Jimmy, and could not be happier. Give the guys at a call, and get a new O tube, expansion valve and accumulator..I agree with GM tech, that if it's just a leak, no need to flush. But the O tube will tell you much more.. Changing the O tube and expansion valve along with the accumulator is just a good thing while the system is empty, but it's not even needed unless the system is contaminated..Personal opinion I guess.. Here's a couple pics of the old vs new compressor.. Hope this helps..
Before with the belly leaker

After with the New Valeo (seltec clone)

Email: Chick


Freedoms just another word for nothing left to lose

alchemist_bobtilton on Sun August 12, 2007 10:34 AM User is offline

I'll definitely buy the o-tube and accumulator from our friends at ACKits, but where would you buy the compressor? I can get cost + 5% on OEM GM parts (makes it about $350, give or take). I see ebay has a few sellers of aftermarket HT6 compressors for under $200. Is there a reasonable concensus on the forum where the most reliable ones can be obtained?


70monte on Sun August 12, 2007 11:20 AM User is offline

You can buy the compressor that Chick recommends from this site( Its only $214 + shipping and its supposedly a very good compressor. I bought it for my 98 chevy truck that I'm about to repair.

A quick question about flushing. Shouldn't you flush things like the evaporator to get all of the old oil out so you add the correct amount of oil back into the system or is the amount of oil in the evaporator insignificant?

My compressor is leaking as bad as the picture of yours you showed but its also making a rattling sound when its running, so I don't know if I have "black death". I just thought it would be a good idea to flush things out.


alchemist_bobtilton on Wed June 18, 2008 8:48 AM User is offline

One question that I have on replacing the accumulator on this vehicle. I see from my 1998 GM factory service manual that it suggests to use a J-38042 "Dual O-Ring Separator", as there are two o-rings on one of the connections at the accumulator. I've replaced many GM accumulators in my day (esp. on mid-90's B-bodies: Caprices, Roadmasters, Impalas, etc.), and I don't recall ever needing one of those tools. But then, I don't recall there being two o-rings stacked on one fitting at the accumulator. Is this thing necessary? Tell me it's one of those unnecessary tools (please).


chillin on Wed June 18, 2008 5:13 PM User is offlineView users profile

just my two cents but you can order everything on this site sealing washers,nylog especially the o-ring kit has all orings for every break and if you should rip or tear you don't have to stop what your doing to chase down. and the hecat flush evaporates nicely. if your going to take the time to replace flushing properly allows you to know you have exactly what the system operates on.remember flush flush blow blow blow and create a back pressure with your hand and let go creating a mist or vapor of the flush you want dry as possible. the cut out prcedure for the rear exspansion valve saves some time. be careful of the dryer accumalator the fitting at the evaporator can gauld .taking the bracket that holds the acc off and removing the coolant tank you can spin it off and on be careful not to twist that fitting sometimes just the nut is gaulded.distribute your oil and pull a nice vacuum for 3min to0 1 hr let set for about 5 min to see if it leaks down you should be good to go dont rush .as chick says do it right the first time and your done.also check out your fan clutch when your done if it is weak could effect cooling when vehicle is not moving.

Edited: Wed June 18, 2008 at 5:47 PM by chillin

chillin on Wed June 18, 2008 5:48 PM User is offlineView users profile

probably 1 hr on the vacuum sorry about the edit.

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.