• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Suburban Dual Air Upgrades

B

bobbiemartin

Author of The DB2 Conversion Guide
Messages
567
Reaction score
22
Location
Jacksonville, Florida
I have a 1995 Suburban with front & rear air. A while back, I changed the compressor, Front evaporator, condenser, orifice tube. Also had to replace the rubber hoses on the compressor (used genuine GM parts). I used the best parts I could find, the cond & compressor were ACDelco. Also replaced the radiator at the same time. The rear air has never been touched. I have the heaviest duty Hayden fan clutch, screw on water pump and Duramax fan.

OK, when the temperature outside is 80 or below, the A/C will freeze you out. 80-85, it is not too bad. 85-90 its getting marginal. Above 90, especially in town, it really never gets cool. So, I'm kind of stumped. I had it refilled with 134 using a very good AC machine, so the charge is pretty close to where it should be.

The engine temps run around 180-190, I don't tow, it basically is a big station wagon for my wife. Thinking of what I can do to increase the AC cooling. I have the external oil and trans coolers and it has the trans cooler in the radiator (came from the factory this way).

Thinking of removing or at least moving the transmission cooler and installing this fan:
http://www.amazon.com/dp/B0012PM154/?tag=jhuntlink-20
I would connect it to the compressor clutch, so it would be on when the A/C is on.

Anyone have any input on this? I have a PML deep pan and the trans runs about 175 so I'm thinking I could get by without the external cooler.
 
As an Amazon Associate we earn from qualifying purchases.
You may need to remove an orifice tube from the condenser; GM condensers have one installed that is only for front-air trucks. Subs with rear air should only have an orifice tube in the Y pipe.


Subject: 93 - 00 Full Size Utilities (GMT400 Old Style Only) AC Blows Warm and the High Side Pressure Is Too High



Models: .



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

The following diagnosis might be helpful if the vehicle exhibits the described symptoms in the PI.

Condition/Concern:

Some OLD BODY (GMT400) style utilities with (C69) rear air conditioning may experience poor AC performance with the high side pressure reading too high.

Recommendation/Instructions:

If no resolution is found through normal diagnosis, check for a orfice tube located in the condenser outlet pipe. Vehicles with the RPO (C69) rear air conditioning should only be equipped with one orifice tube that is located in the "Y" pipe before the Evaporator Core. It is possible that a orifice tube has been installed at the condenser outlet pipe. Please be aware that replacement condensers come with a orifice tube already installed in the outlet pipe. This is due to the fact that this part number condenser is used on the light duty Utilities and Light Duty trucks. Thus, the orifice tube needs to be removed from the condenser on Utility Models that have rear AC only.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

Models:

(93-00 Chevrolet Suburban ) and (93-00 GMC Suburban ) and (00 Cadillac Escalade) and (95 - 00 Chevrolet Tahoe) and (95 - 00 GMC Yukon) and (99-00 GMC Yukon Denali)
 
this same sort of thing happens in my gasser suburban. I say sort or because it blows cold going down the freeway but idle and round town it blows semi cold. Is this due to an extra orfice? I was told by the shop when I had it worked on several years ago that it was just the way suburbans were... this post has me thinking.
 
Kinda sounds like it might have a couple ounces to many of freon. I would pull a couple ounces out an see wat happens. A bigger condenser will help to or your idea of adding a fan might help.
 
Bobbie, I have the same fan on mine, but where the engine oil cooler was. On my old Cummins I installed one on each side.

Also just confirming, you did check the the orfice tube was not in the new condeser? it may have had one installed.
 
Am looking at that fan too, but for different reasons and it seems we both agree there is not enough room in the grill for it *and* the tranny cooler. Subscribing to see if you pull the trigger on it.

For the A/C, mine acted similar last year, but it was from a botched compressor replacement by the previous owner and the lines had fouled; end result was a *complete* system replacement (minus the dash components) where some of the hard lines were scarce and one part for the rear (valve?) was NLA but I got lucky as the mechanic was able to bring it back to life. After the complete A/C overhaul, the system worked normally from idle to highway speeds in the DC nasty summer.

Just putting this out there even though it seems you did all the correct overhaul items per post #1: only thing theoretically missing is rather than top-off or pull-out freon and look for a good high-side pressure, to vacuum down the system and then fill with the correct amount of freon; but something tells me that this is already known.
 
I bought the fan for my Sub with the same intentions to wire it into the A/C clutch and also to a toggle switch so I can force it on when towing heavy if necessary. I plan to relocate the trans cooler to underneath the truck and eliminate the radiator trans cooler.
 
Get a set of guages on it and see what it is doing. I know mine will freeze you out at 100 degrees outside unless I'm towing and the underhood temps are running hot which heats up the A/C lines. Could be a bad rear expansion valve, incorrect orifice tube location, incorrect orifice tube, failing compressor, oil charge off, or wrong amount of refrigerant. Need to knopw if the A/C cycles on and off alot, or if it stays on all teh time first though. Does it get cold at an idle and warm up going down the road, or just ot get cold. Also the aftermarket replacement condensers are more efficient and much smaller and higher flowing than the origanal OEM ones.
 
photo-3a.jpgphoto-3.jpg

I put in a valve to shut off hot coolant flow to the front and rear heater cores. I noticed that the rear A/C was cold, but the front was not. It was likely the front air blend door seals. It would have been over a grand to pull the dash and replace them. The A/C was fighting the hot heater core. By putting in the valve, I now have really cold A/C in the heat of summer. (Well I did, before the DS4 went).

I used an Oreilly murray valve.
 
Possible the rear TXV issue wiped your compressor, see reference below. We never run ours below MED speed for the rear. Not looking forward to doing this to mine. The rear warms up due to a bad TXV or debris in it's screen. The orface tube only filters the front evaporator while the TXV has it's own filter.

Check and see if an in line filter was ever installed and has now plugged up.

http://www.thetruckstop.us/forum/sh...fo-Yes-it-has-a-Thermal-Expansion-Valve-(TXV)
 
Just a quick update. I replaced the control panel with no change. I have ordered the auxillary fan, so will see how that works. One problem I noticed, when the fan is on high, it pulls the recirc door to outside air, regardless of where the recirc switch is. On low fan blower speeds, the recirc door works fine. Once it changes to outside air, you have to change the fan speed to low and the door goes back to recirculation on its own. Increase fan speed and the door is back to outside air. I'm guessing the air is overpowering the recirc door motor? I hope I don't have to replace the door motor, its not a fun job. Any suggestions?
 
largelybored said:
View attachment 32884View attachment 32883

I put in a valve to shut off hot coolant flow to the front and rear heater cores. I noticed that the rear A/C was cold, but the front was not. It was likely the front air blend door seals. It would have been over a grand to pull the dash and replace them. The A/C was fighting the hot heater core. By putting in the valve, I now have really cold A/C in the heat of summer. (Well I did, before the DS4 went).

I used an Oreilly murray valve.
Click to expand...

So, this is put before the tee after the coolant x-over?
 
bobbiemartin said:
Just a quick update. I replaced the control panel with no change. I have ordered the auxillary fan, so will see how that works. One problem I noticed, when the fan is on high, it pulls the recirc door to outside air, regardless of where the recirc switch is. On low fan blower speeds, the recirc door works fine. Once it changes to outside air, you have to change the fan speed to low and the door goes back to recirculation on its own. Increase fan speed and the door is back to outside air. I'm guessing the air is overpowering the recirc door motor? I hope I don't have to replace the door motor, its not a fun job. Any suggestions?
Click to expand...

Been there, done that. Fix the ground to the blower motor. Check the 2 wire plug behind the glovebox that goes to the blower motor as it is also the ground for the A/C servos on the 95. i had this same problem 2 years ago and fixing the ground took care of it.
 
WarWagon said:
Possible the rear TXV issue wiped your compressor, see reference below. We never run ours below MED speed for the rear. Not looking forward to doing this to mine. The rear warms up due to a bad TXV or debris in it's screen. The orface tube only filters the front evaporator while the TXV has it's own filter.

Check and see if an in line filter was ever installed and has now plugged up.

http://www.thetruckstop.us/forum/sh...fo-Yes-it-has-a-Thermal-Expansion-Valve-(TXV)
Click to expand...



Thanks for the link, this is a great thread. I'm afraid I'll need this info soon; I've got no cold a/c, and the compressor cycles on and off quickly.
 
You must log in or register to reply here.
Back
Top