Is your AC not cooling correctly? Technical bulletin:
 

My H2 is an '03. I hadn't noticed it last summer since I bought it late in the summer and I guess I didn't need the AC that much.

That was until the last couple of weeks where the temps are getting close to 100. I noticed (as it seems with most GM's) that the AC doesn't cool as much when I come to a stop.

Typically if the AC condenser doesn't have enough air flow (eg. being at a complete stop), you can help cool the condenser by adding a supplemental electric fan over it.

However, before I jumped on that, I recharged the AC at my shop... it didn't help much so I took it to a tech friend of mine and he checked it out.

Turns out that certain Yukons and H2's have a service bulletin that pertains to the orifice tube being put in backwards from the factory.

He evacuated the system, turned the orifice tube 180 degrees (normally they're suppose to go in one way only... the arrow should point towards the front of the truck) and the AC works perfectly.

Anyway, just thought I'd mention it if any of ya'll don't seem to have your AC working correctly when sitting still at a light.


HTH's,

Mark

Re: Is your AC not cooling correctly? Technical bulletin:
 

Thanks Mark. There's been talk of A/C problems during past summers so I know this info will help some.

Re: Is your AC not cooling correctly? Technical bulletin:
 

What would Freud say about all that?:confused:

Re: Is your AC not cooling correctly? Technical bulletin:
 

That you really wanted to marry your Mother:D

Re: Is your AC not cooling correctly? Technical bulletin:
 

Mark, Same thing here. We had a run of 90's a couple weeks ago and the AC just couldn't keep up. Turns out the orifice tube on mine was in backward too. Dealer fixed it while it was in on other issues and now it works great.

Re: Is your AC not cooling correctly? Technical bulletin:
 

Full bulletin:

Document ID# 1360249
2003 HUMMER H2 Insufficient HVAC System Cooling, Hissing Noise on Engine Shut Off (Inspect/Reposition Orifice Tube) #03-01-39-010 - (Jul 24, 2003)

Important: The Information contained on this DVD is dated October 7, 2005. Please visit your approved GM internet portal for the latest published Service Bulletins, Campaigns and Preliminary Information.

Insufficient HVAC System Cooling, Hissing Noise on Engine Shut Off (Inspect/Reposition Orifice Tube) 2003 HUMMER H2
Condition

Some customers may comment on insufficient cooling of the air conditioning system. Also, a loud hissing noise may be heard when shutting off the engine.
Cause

This condition may be caused by an incorrectly installed orifice tube. It may be installed backwards.
Correction

If the vehicle exhibits insufficient cooling and a loud hissing sound is heard upon shutting off the engine, inspect for a mis-installed orifice tube. Correct the installation of the orifice tube if it is backwards. Refer to Expansion (Orifice) Tube Replacement (SI Document ID #703189).
Warranty Information

For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
D3200
Tube, Expansion (Orifice) - Replace
Use Published Labor Operation Time

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

Re: Is your AC not cooling correctly? Technical bulletin:
 

BTW, mine hissed, slowly and for a while after shutoff before (2 minutes). Now it still hisses, but for a much shorter duration (~20 seconds).

Re: Is your AC not cooling correctly? Technical bulletin:
 

My problem is the opposite. Never had a problem with AC, then while at the dealer for some other issue, they turned the tube around because of the bulletin, and have had non-stop issue of AC not cooling enough since (this was last summer).

They've double-checked the tube, recharged the AC, increased the pressure, decreased the pressure, triple-checked the tube -- but they refused to put it back backwards because of the damn bulletin. Then we hit cool weather and I let the issue go.

HOPING it doesn't come back this summer...

Re: Is your AC not cooling correctly? Technical bulletin:
 

I had my condensor replaced near the end of my warranty period. Then it was winter, so I didn't have to use it....I've noticed this summer that it doesn't seem to be cooling as well as it used to...like you said, especially on the hot days. So, anybody have a diagram on how to check this yourself and turn it around?

Re: Is your AC not cooling correctly? Technical bulletin:
 

Doc,

I think the orifice tube is in between the high and low schrader valves. There is a union nut that you can unscrew and pull the lines apart. The valve will fit either way...

However, unless you have the ability to evacuate and recharge the system, you'll need to take it to a mechanic to have it done. Undoing the lines to take the orifice tube will let the freon escape out into the atmosphere.



Ree,

Until you posted the bulletin, I hadn't realized that the hissing sound was also caused from the orifice tube. I have always noticed I could shut the truck off and it sounded like it was releasing presssure... so hopefully that will be a benefit too.


H2finally,

Do yourself a favor. Take the truck to an AC guy and have them put an actual set of gauges on the system. My techs in my bodyshop use a machine to evacuate and recharge. You set the amount using a digital readout and the machine will install the correct amount.

Point is, I know I have thrown a set of gauges on afterwards and the pressure is wrong and the system doesn't cool correctly.

The high side pressure should run about 230-240 lbs and the low side should be 35-40 lbs. Alot of this depends on the outside temp and other relative factors.

What made me suspect something was wrong (other than it just plain sucked...lol) was my low side was at 60-70 lbs... usually that means the compressor is on its way out.

HTH's,

Mark

Re: Is your AC not cooling correctly? Technical bulletin:
 

He said touch wood:p

Re: Is your AC not cooling correctly? Technical bulletin:
 

Mine has been cooling fine, but never on the right setting. If I put the button on (the one with the snowflake), all I get is hot air. If I leave it off, it cools down great. Never been worth the hassle to take it to the dealer (and wait a week while the wrong part is ordered, returned, then finally fixed).

Stacy

Re: Is your AC not cooling correctly? Technical bulletin:
 

Um, it's a snowflake with a slash through it, meaning turn off AC when you select it.

Re: Is your AC not cooling correctly? Technical bulletin:
 

Its been really hot here lately and ive been wondering if something is wrong. On one hand i think that its just a big truck and takes a while but on the other hand im thinking it should be able to cool off much faster. Ill probably bring it to a local mechanic since the closest stealership is 2hrs away.

Re: Is your AC not cooling correctly? Technical bulletin:
 

x2:)

Re: Is your AC not cooling correctly? Technical bulletin:
 

I don't see no stinkin arrow

Re: Is your AC not cooling correctly? Technical bulletin:
 

BTW, here is an orifice tube

Re: Is your AC not cooling correctly? Technical bulletin:
 

Actually, I think that's the problem. There is no arrow. There is suppose to be one... that's probably how they got put in backwards.

Mark