A/C Temp. at vent?

[DWB]

Help, Trying to gather data to get dealer to fix A/C problem. My 03' has 60-70 deg air temp at the vent and the dealer is saying it's within specs.
Those of you in hotter areas, what vent temp are you seeing and what was outside temp when checked?

[a64pilot]

DWB,
Are you in recirculate mode ? Are you sure the A/C goes in the Recirc mode ? Does the fan noise noticably increase when Recirc is selected ? Not to be insulting, but output air temps will only be useful when compared with intake temps. Normal mode of course is outside air temps and recirc is cabin air temp. I think that a 20 to 30 degree temp drop is about all an A/C system is capable of. Obviously many A/C's obtain about 40 deg. or so output air temp, but they do that by multiple passes of the air through the the evaporator, hence the question of being sure your system is in recirc mode.
In order to be useful, I believe you would need output temps in the normal mode only and know outside air temp as well. I believe the vehicle should have been in the shade for a while to eliminate heat gain from sunlight.

[DWB]

a64pilot, Your right about the varibles, but the bottom line is the dealer and the GM issued TSB for the 03' D/A saying 81 deg is a acceptable vent temp. I say no way! I have compaired the A/C preformance of several 02'and 03' 2500HD (gas trucks) and after a few miles at highway speed, they all manage 40-43 deg vent temp, even when it's over 100 outside. Same day and temp, my truck is doing good to get below 70 and they say that is within specs. I just want to gather some data to determine if it is my truck or a Duramax thing.

[mdrag]

DWB,

No complaints with the A/C on my '01 3500 D/A - and the OK summers are HOT with many days in the 100-105*F range...we had a 104* day before the end of May this year. My wife always asks me to turn down the A/C since it is too cold.

I'll have to remember and check the vent air temps later this week.

IIRC, when the 2500HD received Motor Trend's 2001 Truck of the Year Award, they tested in the desert and remarked how well GM's A/C worked - it was the preferred vehicle used to escape the heat...

What HVAC changes did GM make for '03 to ?improve? :eek: the system??? Could it be the 'hood bludge' actually did something ;) tongue.gif

[GMC D-Max]

Mine's going in tomorrow for (among other things) poor AC performance. We had a "heat-wave" here over the weekend (low 90's), and the AC was USELESS. If 30 below ambient air temp is within spec, mine must've missed it by at least 15-20 degrees!
:mad:

This will be my second trip to the stealer for the AC.

[Lone Eagle]

DWP, Find another dealer. The one you have has absolutely no common sense. Mine runns between 40&45 when recirculating no mater what the outside temperature is. Later! Lone Eagle ;)

[DinoMax]

DWB, I live in So. Florida, and the outside temps always seem to be hot. My A/C is always ice cold. Matter of fact, when I sold my '98 Z-71 x/cab and got the crewcab, I thought to myself, it'll take forever to cool this bigger cab down, but I was wrong. A/C is even better in my '02 :cool: Recirc. mode definately makes a big difference when outside temps start climbing. Haven't had a chance to put temp gauge in vent yet, but I'll try to do it this week & let you know. It's supposed to be in the 90's here all week:( so it should be a good test.

[DalDMax]

Ok I put a digital thermometer in the truck this morning so I could check out the A/C temps on the way home from work and running around this evening.
Today it was kinda cooler then it has been.
Temps are on highway in traffic
Outside temp was 92 :cool:
With Recirc on A/C output was 40 to 44
With Recirc off A/C output was 46 to 49
I noticed that engine speed plays a big part as to how cold it gets. Idle to 1500 rpm and it was at the higher temps, once steady engine rpm above 1500 it got to the lower numbers.

If I can do any other testing for y'all, just let me know smile.gif

[rcarbs]

I live just outside of Phx AZ. The end of last week we were in the 107 to 109 range. My '03 D/A 2500HD had no problems freezing me out if I needed it to. I normally have it set on 74, it initially goes into the recirc mode(inside cab temp >130) then changes to the normal mode. If GM says 81 is within spec....they must be talking about the evaporative cooler at the dealership not the AC on your truck.

[dave p]

this air conditioner is weak compared to my 98 chevrolet 2500. i put limo glass tint in rear and rear side windows, it helps a little. 98 truck was a better truck, all the way around. would never buy chevrolet again, have had 40 service calls in 31000 miles. dave p

[hoot]

Originally posted by dave p:
this air conditioner is weak compared to my 98 chevrolet 2500. i put limo glass tint in rear and rear side windows, it helps a little. 98 truck was a better truck, all the way around. would never buy chevrolet again, have had 40 service calls in 31000 miles. dave p I had a '97 6.5TD that was a very good truck but I cannot say this one is worse. Some things aren't as good but I feel the suspension and drive train is better, with the diesel and Allison hands down.

I have had mine over two years and 53,000 miles. Only been in for defueling, airbag light, serpentine tensioner pulley, bigger driveshaft, and a power window switch. Service was excellent, especially with evening hours. Truck has only been in twice for these things and left overnight only once.

I have the auto climate control that I absolutely love. A/C has no problem at all in these humidity laden hot Northeast summers although lately it's been a cool wet Spring.

Sometimes you get a troublesome truck. You may not buy GM again but you won't guarantee yourself a perfect truck no matter where you go.

Forty service calls? Isn't that lemon law/buyback territory?

[ 06-11-2003, 05:48 AM: Message edited by: hoot ]

[Mike Fultz]

One other note... Don't run the fan at the fastest speed when your trying to cool the truck down. If you turn the fan down a bit, it will allow the air crossing over the coils to be a bit cooler at the vent. I will run the re-circulating button and crack a rear window. The truck seems to cool down quicker. The only annoyance is you have to keep turning on re-circ everytime you get in the truck with the automatic controls.

[huntindog]

The 20-30 degree temp drop statement is hogwash.
I live in Phoenix, and always let the automatic control do it's thing. I have it set at about 74, and it goes into recirculate as needed. Usually when the truck is first started,then it switches over. I have never checked the temp at the vent as it's always cooled great. 110 is very common here, so I know when a ac system is working right.
I will take some temps and report back.

[cowboywildbill]

Have your dealer replace the A/C relay. It is in the fuse box under the hood. It sounds like it could be the cause. It is cheap to try. It could be a restriction in the system also. Did they say what the Hi and Low pressures were? Also you might have a problem with the vent door, that opens and closes from the heater box. It might not be closing or opening all of the way. There are also filters in the cab, check them. There is a posting about them here somewhere.Maybe you should try another dealer. Mine is an 02 and it gets ice cold 40 deg. F. in the hot summer days.

[huntindog]

Ok, here's the results of the test.
Outside temp 107 at 5:45 pm
climate control off and fan on high
3 miles on the highway at 60 mph
out side air button on
vent temp 48 degrees
turn around and retrace route
recirculate button on, fan still on high only blowing much harder now
vent temp 48 degrees

Exit highway and turn climate control on.
After a mile of residential driving (arrived at destination) temp is 44 degrees!

Recirculation appears to have NO effect on actual vent temp, just the volume of air, which has the effect of increased cooling.
Also notice that the temp drop from outside was 59 degrees!

Go back and tell that dealer he's FOS.
Also, Iv'e never replaced the filters and have 28,000 miles with a lot of dirt road driving

[oyazi]

My only gripe w/the 01/02s is that recirculation really isn't. There is even a comment in the manual about that fact. I think recirculation should mean just that. Put it into the recirculation mode and turn off the fan ~ put hands in front of vent and one can see what I'm talking about. One would hope the 03s would've been different.