Another '03 A/C Temp. Question?

[Buffalo]

My '03, QC has been pretty uncomfortable, lately. After about 10 miles of driving, the drivers dash vents only get to a bit over 60*.



In May '06, I had to replace the A/C pump & all the plumbing. The inside of the pump disintegrated leaving metal everywhere. The A/C never really worked as well as I thought it should. Freezes up during the monsoon season, here in Arizona (lots of humidity). The reat of the time it never cools as well as I thought it should.



I took it in to a repair facility & they said that the "low side" was low on freon & topped it off. It has definately helped. The temps now are just below 60* in the drivers vents. Before, the passenger vents seemed to be pumping ambient, in cab, air temps. They are better, now. Have you guys found these temps to be normal? My Duramax buddies say that their temps are in the 30* range.



So far, this is another one of my dissapointments with this truck. It always runs but, seems to have a lot of convenience/comfort issues.



Joe F.

 

[Bob4x4]

I do not think your Duramax buddies are being honest... ... ... to blow in the 30's in Phoenix summertime they would have to be doing at least a 70 degree drop. That is unrealistic. @ 110 degrees an outlet temp of below 60 is not out of line.



Bob

 

[Matt400]

In May '06, I had to replace the A/C pump & all the plumbing. The inside of the pump disintegrated leaving metal everywhere.

All the plumbing, would that mean the evaporator too?

In our shop we shoot for 43 degrees on the vent temp and anything below is a bonus but if its hotter something is wrong IMO.

So far, this is another one of my dissapointments with this truck.

I owned an 03 and it cooled just fine, especially after the A/C TSB. but that one is for warm vent temps during idle conditions.

 

[LRutigliano]

This last weekend, it was 85-90F x 40%RH and my vent to the right of the steering wheel was putting out approx 50F air while travelling at 55-65mph on blower speed 2 in recirc.



Lower blower speeds will get you colder temps. Operating in recirc will get you lower temps.



60F doesn't sound too unreasonable in Phoenix, especially if you are running in town.



Sometimes, moving the temp knob(s) from full cold to full hot and back again will reset the blend door(s). I'm not sure if our trucks have electric actuators with a feedback loop, but if not, the actuators can get "lost" over time and not be fully closed even though the temp knob is at full cold.



Run it down the freeway at 60mph and your temps should come down. You need the ram air thru the condenser.



Also, be sure to use a digital thermometer with a long metal probe that you can stick down into the vent. The analog ones are sometimes inaccurate.



Your DURAMAX buddy is lying to you. If he were getting 30F air out of the vents, his evap core would be frozen. The lowest you should be able to get out of the vents is approx 40F because the evap core isn't allowed to get to 32F.



Hope this helps,

Louis

 

[jelag]

Louis is right. . any moisture in the vehicle will freeze if the evap core temp is below 30..... its frost first, and as the frost impedes the air flow the frost continues to build until it freezes solid... now the air can't flow through the system and the air warms...

We shoot for 40* when we test our systems... I keep a small thermometer in the vent and measure the temp. .

What concerns me is that you didn't mention if you back flushed the lines when the first compressor failed... . any kind of dirt can cause problems... a reed valve in the compressor stuck open so it can't function correctly. .

Also you didn't mention if you've leaked checked the system, either with dye or other tests. Low on 134a can lead to warm air...

I read an article on the new sealers for these systems (134a) that are activated by the atmosphere now use a 2 oz charge of sealer if and when I have the system open...

I don't know if our trucks have a fixed orifice or expansion valve... I've never checked... but on a fixed orifice design system any thing that can clog the screen will hinder the flow. .

Hope this helps...

 

[Buffalo]

Thanks for all the replies!!! I feel better that the A/C is working properly.



My one Duramax buddy is capable of enhancing the abilities of his truck.



I'm not sure what the evaporator is. My guess is that it is under the dash & is like a radiator that the warm, in-cab air blows over to pick up the cooling. As I recall, the mechanic blew out the rest of the system that wasn't replaced.



Two years ago, the A/C was replaced. Here is a list of the parts that were replaced:



55056935-AB Line A/C 24028024- $67. 13

55057016-AA Condensor 24027005- $81. 00

55055339-AH Compressor 24025005-$395. 25

55055960-AA Line A/C 24028024-$55. 88

82300102-Lubricant 1081033-$30. 53



Don't know if this helps, or not but, this is what got replaced.



The temps. have been very hot, here, lately. However, it's pretty dry from a humidity standpoint. We are just now starting to go into our "monsoon season" which will increase our humidity, greatly. Lots of cloudiness in the afternoon's & a fair amount of rain.



In the past, I have experienced the A/C system freezing-up. The air gets warm & if I shut the system down, for awhile, & turn it back on, it starts cooling, again. This happens during the "monsoon" & I wasn't using "recirculate", either. Takes awhile for old dogs to learn new tricks, I guess.



Thanks again, for your help. Sure do appreciate you guys sharing all your knowledge.



Joe F.

 

[JanMitchell]

service bulletin

The A/C on my '05 quad cab hasn't been cooling as it should and it seems that the passenger in the front seat did the most complaining. Yesterday I was talking to a fellow with a similar truck and he said the problem could be with the air blending door in that it could be stuck and warm air is being blown into the cab. There is a service bulletin concerning this and sure enough when I went back in my truck the passenger side was blowing warm air and the driver's side was cold. I'll have to take it to the dealer and get it fixed. Not that we use our A/C in Las Vegas

Stan

Not a chick

'05 Dually 6 speed Quad cab

 

[DPKetchum]

Low freon will cause the passenger side to be warm. It will also cause freeze up. On early trucks there was a change of the position of the fin temp sensor on the evaporator to stop freezing when the system is working correctly.