1997 Suburban dual AC question

[brushwolf]

I got a new ac compresser and condenser kit for dual air 97 Suburban. I found the original orifice tube in the split line by the battery box. It was very stuck and came apart rather than coming out. Took the line off too and then took out all the remains of what apppears to be what was once a white orifice tube. Then cleaned the line well several times and installed the new yellow orifice tube which had come packaged separately with the kit. Fit just fine.

However, when I was installing the new condenser I found it also had an orifice tube in it. The original condenser did not have one. So I removed that one from lower line of condenser figuring it must have been included for applications that have only front air. That new orifice tube is black plastic. IDK if the color matters, but figured it did not need 2 orifice tube at the front.

The kit also included a brass orifice valve for the rear unit. So the extra one I am assuming is just because they sell partial kits like this for single air applications.

Am I wrong?

 

[brushwolf]

P.S. The kit also included a new dryer which is installed. Going on to the compresser replacement now, but thought now is the time while the system is empty on freon to be certain on the confusing issue of the kit including 2 orifice tubes, plus the orifice valve for the rear unit... I remember when instructions used to come with parts...

 

[grampadirt]

I use a white orifice tube,others use different colors for their reasons.That brass part is an expansion valve and is used for the rear a/c and is behind the panel on the right rear of your burb.

 

[GoToGuy]

Why aren't you using the free OE service manuals offered here? The complete system breakdown , the difference between truck, sub, Tahoe and rear options . It's step by step. Doing it with OE reference , no mistakes.

 

[1998_K1500_Sub]

I got a new ac compresser and condenser kit for dual air 97 Suburban. I found the original orifice tube in the split line by the battery box. It was very stuck and came apart rather than coming out. Took the line off too and then took out all the remains of what apppears to be what was once a white orifice tube. Then cleaned the line well several times and installed the new yellow orifice tube which had come packaged separately with the kit. Fit just fine.

However, when I was installing the new condenser I found it also had an orifice tube in it. The original condenser did not have one. So I removed that one from lower line of condenser figuring it must have been included for applications that have only front air. That new orifice tube is black plastic. IDK if the color matters, but figured it did not need 2 orifice tube at the front.

The kit also included a brass orifice valve for the rear unit. So the extra one I am assuming is just because they sell partial kits like this for single air applications.

Am I wrong?

You are correct

One orifice tube for the front evaporator, located after the Y.

One TXV for the rear evaporator, mounted on the evaporator itself.

The TXV has a screen in its inlet, much like an orifice tube has, to catch debris. If the original orifice tube you removed up front had debris in its screen, the TXV will too.

You may find that ALL the rear AC fittings are corroded and inseparable, which was my experience. I had to replace everything from the engine bay rearward after cutting the old stuff out.

 

[brushwolf]

Thanks for feedback guys! I only use this Suburban for towing a car trailer, so I might just skip the apparent nightmare of messing with the rear unit. Hard to tell how much junk was in the tube I took out since it came out in so many pieces. Way worse than 2004 Mustang one I took out a couple weeks ago though.

Can't tell if the debris that came from the line where the old orifice tube was consisted of just tube parts or whether there were also some fine aluminum particles in it. Best to block off the rear lines to avoid any contaminants in those lines making its way to the front?

PAG oil that came from old (2003 mfctr date) compresser, drier, and condenser did not look too bad though. That compresser had started making noise when I was down in MO hauling a project car back to MN back around 2012. Noise stopped when I unplugged the compresser and I have used it that way since way back then and put another 35k miles on it. Removed the old compresser and it still turns ok and had some oil left in it which had no evident particles.

Put vacuum gauges and pump on the system before disassembly and it had zero pressure, but it held the -29-30 vacuum from the pump for a couple days before I took any parts off. But if does not leak, where did the freon go?

 

[1998_K1500_Sub]

Best to block off the rear lines to avoid any contaminants in those lines making its way to the front?

There are "block-off" kits out there, as you may know, "plugs" that replace the rear lines at their front fittings.

I'm sure you already know to reduce the refrigerant and oil charge accordingly. IMHO follow the "front air only" refrigerant and oil charge specs, e.g., from a reg-cab truck.

old compresser ... still turns ok and had some oil left in it which had no evident particles.

That's encouraging.

Did you remove and flush out the front hardlines, and collect the flush so you could examine it for debris?

Did you flush out the front evap, collect, examine?

Replace all the O-rings? Lube the O-rings and fittings with Nylog Blue?

Put vacuum gauges and pump on the system before disassembly and it had zero pressure, but it held the -29-30 vacuum from the pump for a couple days before I took any parts off. But if does not leak, where did the freon go?

Perhaps you had a leak at the service fitting(s), that's fairly common, which was masked by the connected gauge lines. I always replace the service fittings / valves when servicing a system, that's just me.


You haven't said, but I'm surprised your rear lines haven't corroded and developed a leak (assuming you're in MN). That's happened twice on my Sub over the years.

 

[brushwolf]

Yes, the valve leaking would explain why the gauges held vacuum even though the freon had all gone away..

Yes, this MN Suburban has rust underneath and I have had to replace rusted gas tank, and gas lines just now, rear and front brake lines a few years ago. Gas tank project got away from me and I even replaced the frame-mounted receiver hitch, back bumper and lower rear quarters (inner and outer) all due to rust. So I will probably just block off the rear lines rather than take the risk of those springing leaks too. Didn't plan on making this my life's work, just to stop the gas leak (rusted at seam so it did not leak if kept under half a tank.

But it looks a lot better and feels safer now. AC I should have probably not have bothered with since I seldom use it anyway and lucky if I put a thousand miles year on it now. It generally has not been used in winter for the last 10 years either, but once the rust starts it does not stop. May slow down a bit though...

I bought this truck off a car lot when I was on the way to Arkansas to pick up a 60 Impala 2 Dr hdtp. Reason being my Dodge had burned up the computer on the way to Arkansas and no replacement was available in the time frame I had to work with. Figured I would just sell it again once the newer Dodge was fixed. But I became fond of it and sold the Dodge instead after a few months driving the Suburban.

It has been an unusually reliable vehicle for the most part though. Never has once stranded me, although I have limped home a couple times. Sure uses a lot less gas than my 87 Suburban, but that one is 3/4 ton with 454. And the 97 seats are just so comfortable it really puts my much newer Ford pickup to shame. So, it deserved a bit of overdue repairs. Never once had a flat tire on it either with over a decade of ownership and 50k miles added to odometer. But it still has the same tires as when I bought it, so that is probably next...

 

[brushwolf]

Why aren't you using the free OE service manuals offered here? The complete system breakdown , the difference between truck, sub, Tahoe and rear options . It's step by step. Doing it with OE reference , no mistakes.

Where in the forum is that located? I looked around, but did not see it...

 

[GoToGuy]

There is a sticky above or search for Haze's thread on service manuals, or search for Service Manuals.