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Repair and flushing the system

torque395 on Thu July 28, 2011 5:57 PM User is offline

Year: 1996
Make: Chevy
Model: Suburban
Engine Size: 6.5L
Refrigerant Type: R134A
Country of Origin: United States

Id like to flush the system on my 96 Suburban (WITH rear AC) and replace the o-rings, o-tube and accumulator. Possibly even the compressor and upgrade to a newer and better condenser that is available for this truck that would surely make the AC work better.

How would I go about doing this? I know you guys like to push the hecat flushing system, but i am just a private individual working on one AC system (probably will do one more AC system after this but thats it) so I dont want or need a big expensive commercial flushing system. I got a quote of $1150 to flush, replace the bad o-ring, o-tube, accumulator and refill and thats just too much IMO. And the guy said you just take the lines off the compressor and flush through one and it comes out the other. Said they didn't even take the lines loose anywhere but at the compressor, or remove OR replace the TXV either one. He said they just flush through it.

I thought you had to replace the TXV anytime you opened the system and I thought you weren't supposed to flush through it either?

There are three lines coming off my compressor. Two i believe are big lines, low pressure side? And one smaller one. One goes to the rear, the other to the front evap.

Which of the 3 lines do I flush into and do I need to remove them all and flush them separately? Can I just pour in the flush with a funnel and blow out with dry compressed air? If i buy a 5 gal jug of flush and use the whole thing that way will it be good?

Also can I use lacquer thinner to flush it with? If i happen to not get all the flush out (which i should, it dries very easily) will the suction from the vacuum system remove whats left when i vacuum the system down ?

Please help! I want to save myself some off that 1150, or even if I spend 1150, i want to end up better off than I would be with them doing it for 1150.

Also how good are reman AC compressors from oreilly automotive? Is there a good aftermarket compressor that will fit in place of my HT6 and be reliable?

thanks in advance!

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

robs on Thu July 28, 2011 7:39 PM User is offlineView users profile

Well if you want to save some money, you'll have to roll up your sleeves. First you need to know whats wrong with the system then figure out what you want to do. But if the compressor is shot and there is debris in the system, I have you at $416.88 plus freight for a New Sanden Direct replacement compressor (which I would highly recommend) Condenser, Accumulator, Orifice Tube, Expansion Valve (for rear unit), o-ring kit, oil and nylog. Now as far as flushing goes, you'll need to remove your lines and evaporator and take it to a shop to have them flushed if you don't want to fork up the money for good quality flushing equipment. Would not use anything else other than AC flush if you want to tackle it yourself. The rest is a matter of putting everything back together and taking it to a shop once again to have it vacuumed down and charged. It is ridiculous you got quoted $1150 to only flush, replace the bad o-ring, o-tube, accumulator and refill. That should be the cost of a whole compressor job.

torque395 on Thu July 28, 2011 8:04 PM User is offline

Yes the way I understand it it was 1150 for front and rear system to be flushed plus otube, accumulator, o rings, vacuum and fill.

If youve got me priced at $420+ freight then i think ill definitely be ordering parts from you in the near future. All I have to do is sell my zero turn lawn mower that I no longer need and then i'll place my order. I can buy a flush gun i think its called (canister and gun that connects to compressed air) and flush the system that way if that will work, otherwise i'll see about taking it somewhere and having that done. I dont want to $500 or $1000 in specialized equipment for just this job and one other, if that $100-$150 flush gun kit wont work. .

I can borrow a vacuum pump to pump down my system, and infact I have done that on this truck before, but lost all that when that o-ring began to leak.

The compressor is still good - but with 275k on it (had about 160k on it when the ac quit) and it being a leak prone HT6, id rather just replace it. The condenser that you quoted me, is that the one that is an improvement (Parallel flow i think its called) over the stock type unit?

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

70monte on Thu July 28, 2011 11:05 PM User is offline

The labor is where a lot of shops get you. You can save a lot of money doing it yourself. I have done three vehicles like what you have. Two 98 trucks and one 99 suburban.

Your truck should already have a parallel condensor in it but I would replace it anyway because they are about impossible to flush and yours has a lot of miles on it.

I used the Seltec/Valeo compressors from this website on my 98 trucks and used the Sanden compressor on the suburban.

I would also check and make sure your fan clutch is working correctly as a bad one may cause the system to not get as cold as it should.

I would look at the condition of the connections and the lines on the rear portion of the system before deciding to take them apart. The lines go under the vehicle and can rust up and supposedly these lines are pretty expensive to replace if you damage them.

Wayne

torque395 on Thu July 28, 2011 11:36 PM User is offline

Quote
Originally posted by: 70monte
The labor is where a lot of shops get you. You can save a lot of money doing it yourself. I have done three vehicles like what you have. Two 98 trucks and one 99 suburban.



Your truck should already have a parallel condensor in it but I would replace it anyway because they are about impossible to flush and yours has a lot of miles on it.



I used the Seltec/Valeo compressors from this website on my 98 trucks and used the Sanden compressor on the suburban.



I would also check and make sure your fan clutch is working correctly as a bad one may cause the system to not get as cold as it should.



I would look at the condition of the connections and the lines on the rear portion of the system before deciding to take them apart. The lines go under the vehicle and can rust up and supposedly these lines are pretty expensive to replace if you damage them.



Wayne

All I know is that the parts store lists two condensers for my truck. One that it calls a serpentine condenser (whatever that is) and one that it calls a parallel flow condenser. Maybe one is a cheaper replacement to the original parallel flow condenser I dont know.

Rob said he had a new Sanden direct replacement compressor which sounds like the best route to me.

The fan clutch works good, kicks in at 210 like it should (have done that a few times) and the PO says that the truck has never had great AC especially at idle. Truck is diesel so maybe the low idle speed (550) causes that, but I think its the use of a clutch fan that moves only a little air at idle. I've thought about an electric fan at least to supplement cooling. but it may restrict the flow of the clutch fan when it has to kick in I dont know.

Anyways the rear lines have only been together a couple of years, I replaced them in 08 or 09. However I'd like to flush the system all together if i can (minus the condenser and accumulator). I'm going to purchase the Mastercool AC flush kit that ACkits has on their site. That should be fine seeing as they offer it for sale. I'll use purpose made AC flush solvent too. I am going to do this right so hopefully I wont be fixing this every year or every other year. I'd like to replace ALL the o-rings in the system also, but I was told that could end up being a HUGE can of worms.



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1996 Chevy Suburban 2500 4x2 6.5L Turbo

TRB on Thu July 28, 2011 11:48 PM User is offlineView users profile

Thanks for the support Monte.

Lets be clear on the flushing. It needs to be done correctly per Hecats tech paper or one can cause more issues than one would like. We can discuss all day on the type of products to use. But what ever is used if left behind is going to kill the repair.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

torque395 on Fri July 29, 2011 12:22 AM User is offline

So whats the proper way to flush the system? Take it all apart? I cant really remove the front evaporator - that would take forever and leave me without a truck because its a huge PITA. All I can say is I hope i never have to replace it or the heater core. Id like to flush it all in place if possible, but i'm no expert, I dont know what can be done assembled and what cant. I'm hoping to find that out here.

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

TRB on Fri July 29, 2011 1:11 AM User is offlineView users profile

Read Hecat's Tech Paper.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Jase007 on Fri July 29, 2011 2:19 PM User is offline

Torque:

Any decisions on next steps?

I've read the Hecat tech paper and looked at the H1000 flushing machine, etc.. and am facing the same issues on re-doing the AC on my '99 OBS K1500 Suburban (5.7L , not the diesel like yours). I've checked with local indy garages and none disconnect all components on systems with rear air. So .. suspect they are attempting flush through long under-truck lines to rear AC and through TXV to evaporator with refrigerant / HFCF-141b (Dura 141).

I have all the components in hand (AC Delco parts) and am investigating best ways to:

1. access TXV in rear Aux AC (interior removal)
2. disconnect rear evaporator connections / lines for evap flush (will use penetrating oil)
3. connect to flush rear evap

I did not have a compressor implosion ... just a "belly leaker" and high/low side service port(s) failure(s).

Let us know how you make out.

Thanks.

-------------------------
Jason

1999 GMC K1500 Suburban SLT
5.7L Vortec with C69 Rear Aux Opt,

TRB on Fri July 29, 2011 2:26 PM User is offlineView users profile

Hecat provides more options than just the H1000. A hand held flush gun is not a good choice for the extended flush a system of this nature requires.

Hecat Products.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Fri July 29, 2011 at 2:27 PM by TRB

torque395 on Fri July 29, 2011 4:30 PM User is offline

Quote
Originally posted by: Jase007
Torque:



Any decisions on next steps?



I've read the Hecat tech paper and looked at the H1000 flushing machine, etc.. and am facing the same issues on re-doing the AC on my '99 OBS K1500 Suburban (5.7L , not the diesel like yours). I've checked with local indy garages and none disconnect all components on systems with rear air. So .. suspect they are attempting flush through long under-truck lines to rear AC and through TXV to evaporator with refrigerant / HFCF-141b (Dura 141).



I have all the components in hand (AC Delco parts) and am investigating best ways to:



1. access TXV in rear Aux AC (interior removal)

2. disconnect rear evaporator connections / lines for evap flush (will use penetrating oil)

3. connect to flush rear evap



I did not have a compressor implosion ... just a "belly leaker" and high/low side service port(s) failure(s).



Let us know how you make out.



Thanks.

Hello Jase. Yes accessing the rear TXV requires interior removal and a significant amount of it. If you get the rear evaporator core apart from the lines you will be a very lucky person. I had to replace both the lines an the evaporator on mine (in the rear). I tried every salvage yard in the area an only one was able to successfully get the lines apart from the evaporator. Also every AC tech I've talked to said they usually dont come apart (one fitting is soft aluminum, the other is hard steel and they bond together like crazy). I used plenty of WD-40, PB blaster and a propane torch and was not able to successfully remove my originals. To get new lines and rear evap will set you back about $500. If you can get a good used set (hard to come by like I mentioned above) you can probably get it for $100 to $150.

To remove the rear TXV requires the ac box to be removed which of course requires the removal of the lines like mentioned above. There is a service bulletin posted by GM several years back about cutting the box to get to the TXV (after interior removal) and then taping it back together afterwards but personally I wasn't willing to do that. Once its apart its no biggie to work on.

I did this stuff to my truck about 2-3 yrs ago, but didn't really work on the front much, i just threw it together to get it to work "for now" and would do it right later on (which is now). Thats how I know how to do the work in the rear.



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1996 Chevy Suburban 2500 4x2 6.5L Turbo

torque395 on Fri July 29, 2011 4:34 PM User is offline

Quote
Originally posted by: TRB
Hecat provides more options than just the H1000. A hand held flush gun is not a good choice for the extended flush a system of this nature requires.



Hecat Products.

I was quoted today $45 plus the solvent to flush my system. That sounds kinda cheap to me. How about you?

The guy said that would be with me loosening the rear lines - he didn't want to mess with it, he said he'd just plan on replacing them (like I mentioned above that would be about $500 if i couldn't find used ones). I think mine will come apart since its only been 2-3 years since it was apart last. But still $45 sounds cheap to flush my system. That probably doesn't include flushing with nitrogen to clear the system of any remaining solvent if i was to guess. However this guy has supposedly been doing mobile AC for 30 years so he must know what he's doing and he said he did a truck just like mine not too long ago. so IDK what to do. Trust him, or no.


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1996 Chevy Suburban 2500 4x2 6.5L Turbo

70monte on Sat July 30, 2011 2:08 AM User is offline

On the 99 Suburban I repaired last year, I did not mess with the rear lines at all. All of the connections that I could see looked leak free but I did not access the rear evap.

I have one of the mastercool flush guns and I wouldn't recommend it if you are trying to flush anything big like a condensor. It works okay on lines and the evap. I generally just replace the condensor because most of the things I've worked on have been at least 10 years old and I would rather start with a new one than trying to flush an old one.

If you just have a leaking system without a compressor failure, I would leave the rear part alone unless you know for sure part of it has a problem.

As far as the clutch fan goes, the new one I put on my 98 K3500 roars like crazy when you first start the truck up and when the truck gets warmed up. It has the 454 in it so it gets pretty hot under the hood. I think I mine is a severe duty one from Autozone. The AC on it will get down in the high 30's through the vents at idle. Are you sure that your fan clutch is working like it should, especially if you are not having great AC performance at idle? Most fan clutches are shot by 100,000 miles and many of the aftermarket ones don't seem to last as long as the original's did. I bought the Autozone one on the recommendation of a long time GM tech. He recommeded that one or a OEM one.

Wayne

Edited: Sat July 30, 2011 at 2:19 AM by 70monte

torque395 on Sat July 30, 2011 10:23 AM User is offline

The problem I have with this system is that the previous owner is a guy I work for and he is known for putting in refrigerant that has oil in it. I know he added several cans of refrigerant with oil to this thing when he had it so i am 100% sure it has way too much oil in it. That is why it needs to be flushed.

I plan to replace the compressor and condenser (and the other things that are normally replaced), so everything else can be flushed.

I'll look into the fan clutch but it does roar a little on start up, You can barely hear it, but it does roar. Perhaps not strong enough? Anyway it keeps the engine cool, and that old diesel puts out some heat too. I'll look at the Autozone fan clutch tho because a new clutch couldn't hurt anything any.

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

Jase007 on Sun July 31, 2011 3:54 PM User is offline

Torque:

Ive tried the same "methods" on the rear connections (lines to evap) ... they aren't budging. I have the canister / compressor gun and have flushed the front evap and all the lines/pipes in the front. Am replacing the manifold line to the compressor (one with two mufflers) and have new O-rings, 34 row condenser (old was 29), accumulator, OT, etc...

Everything is in ... loosely connected, just trying to decide what to do about the lines running to the rear. At the least, if I could break them free in the back I'd flush the lines. I'm not opposed to eventually getting the lines replaced with barrier hose kits and correct GM connections (kit sold at autocoolingsolutions.com and other places.)

I had cold AC in the rear .. the front got warm when system was low on charge. No leaks visable with dye in lines to the rear ... even at trouble spot under passenger rear seat / front of rear fenderwell). No debris in the lines or OT screens.



Wayne:

When you did the repair on the '99 Suburban and left the rear lines alone ... how much oil & r134 did you put in? My system charge leaked out and there was oil on the under-belly of the belly leaker compressor (lots). I've pulled 3.5 oz from the compressor and accumulator and would guess another 1 to 2 oz came out of the front evaporator and manifold line. System calls for 11 oz of PAG 150 ... I'm assuming I've pulled between 5 and 6 oz out.

Original accumulator calls for "3 lbs, 8 oz" of r134a = 56 oz ... a little less than the 4.0 lbs / 64 oz I've read all across the Internet and supposedly from alldata.

Thanks and sorry to muck up your thread Torque.

-------------------------
Jason

1999 GMC K1500 Suburban SLT
5.7L Vortec with C69 Rear Aux Opt,

Edited: Sun July 31, 2011 at 3:58 PM by Jase007

torque395 on Sun July 31, 2011 7:55 PM User is offline

I somewhat halfassed the AC in my trucck today. It will cost me more in the long run, but until I get the money for all the new parts, the old stuff will have to do. I replaced the accumulator, o-tube, several orings including the compressor orings, blew out alot of the lines individually and re assembled (again with new orings). I did absolutely nothing to the rear. It is 100 degrees here today and the AC was cold. I dont know how cold, but it was cold and I was comfortable in the truck.

Again I did nothing to the rear, didnt even blow through the lines. Ill get you some temps tomorrow or something.

BTW high side is sitting at about 225 and the low side about 55-60. Its HOT today so the low side is a bit high. Not sure about the low side how it is. Maybe someone else can tell me.

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

torque395 on Sun July 31, 2011 11:23 PM User is offline

Here are some temps for you. At 83 degrees this evening the AC was 60 at idle, 50 driving. Thats on max ac.

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

ebacon on Sat July 06, 2013 2:27 PM User is offline

I am rebuilding the ac in my 99 suburban after a belly leaker fail. When i pulled the orifice tube up front there was a noticeable amount of metal attached. It wasn't awful but it was noticeable and so i decided to replace the condenser as well. The rebuild kit i bought also included a rear expansion valve which, if there was metal in font, then prob metal in rear. I would like to flush and replace rear valve and have disassembled as much as i can but there are 2 screws in the rear housing between the housing and the fender that i can not reach. Do i need to crawl underneath and disconnect heater core and lines from under the truck or is there some other way to access the rear expansion valve? any suggestions on reaching the last two screws?

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