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Poor A/C at idle

243K views 423 replies 163 participants last post by  chem_man 
#1 ·
Does anyone have any problems with their A/C not working as well when they are stopped and it is pretty hot outside (90 degrees plus)?

My dealer is trying to get out of fixing, but I don't give up that easily.

My friend has an 05 and he just had his fixed for the same problem, he said they fixed some kind of vent that was letting outside air into the truck.

I figure if I go into the dealer and tell them what I want them to check, they'll fix it. Either that or they will just get sick of my persistance and just start replacing stuff till they get it (unlikely).

Anyway, some suggestions would be greatly appreciated! :D
 
#28 ·
I gotta a bridge you might wanna' buy...

:confused: Hey Guys... Whoever told you the bulletin I previously posted was for EXT chassis only was involved with too much "sucky-sucky" on the "happy pipe". Ask your dealership if they could pull up that bulletin number on their TIS 2000 so you may read it. If they can't find it by Technical Service Bulletin number, the Document number is...like...1671108...man... If after the smoke clears, they can't find it, post a fax # to my private message section and I'll fax you the complete bulletin.
 
#29 ·
I'll be honest, I'm an A.C. whore. I HATE heat so I use the air conditioning more than anyone I've ever met.

From my experience, all cars I have ever owned or driven seem to cool the car better while driving than while stopped. Sometimes it's very noticable, sometimes it's not- but it's always there.

I've always assumed it does that because the engine isn't turning the compressor fast enough, similiar to the way that the headlights in some cars will get brighter when you step on the gas because at idle the alternator isn't turning fast enough to be at it's maximum efficiency.
 
#412 ·
I'll be honest, I'm an A.C. whore. I HATE heat so I use the air conditioning more than anyone I've ever met.

From my experience, all cars I have ever owned or driven seem to cool the car better while driving than while stopped. Sometimes it's very noticable, sometimes it's not- but it's always there.

I've always assumed it does that because the engine isn't turning the compressor fast enough, similar to the way that the headlights in some cars will get brighter when you step on the gas because at idle the alternator isn't turning fast enough to be at it's maximum efficiency.
This actually happens because at idle or low speed you have limited airflow across the condenser. In high ambient temperatures you have the added problem of the condenser being in close proximity to the radiator. Since the condenser isn't reducing the coolant down the compressor is not as efficient in pumping the refrigerant through the evaporator.
 
#30 ·
I agree AC's cool better when being driven. But my TB blows some serious hot air with the AC on until you start driving the thing. Increasing the RPM's in Park to 1000 or 1500 doesn't help a bit. The car we traded in (a 01 Grand Am 4cyl) and my current truck (02 z71) blow cold air in Park, and it only gets colder upon driving it.

04TBEXT: You've got a message... :)
 
#33 ·
I found something on the A/C Problem. Not working very well when at idle. GM KNows About it..

Bulletins - October, 2002

01 – HVAC

02-01-39-005; HVAC System Inoperative for a Drive Cycle, Poor HVAC System Performance in High Ambient Temperatures (Update HVAC Control Module Software); 2002-03 Chevrolet TrailBlazer, EXT, GMC Envoy, XL, Oldsmobile Bravada

Dunno If this will help or not..

Russ
 
#36 ·
02EnvoySLE Guy said:
Was your recirc on? I swear I've never had a problem with my AC blowing warm under ANY circumstances.
My recirc is always on when I have this problem, but it also does it when it is off. It only happens to me when its really hot outside. Early in the morning and late in the evening, snow flakes come out of those vents!! :eek:
 
#38 ·
OK, it hit 98 here yesterday and I see what the complaint is about. Even under recirt and after 15 minutes of driving, when I would slow down, or sit still at a light the air would get warm. Felt like I was on vent. :( Now I can see why people are upset. Before now it has only got up to around 87 or so.
 
#39 ·
MoJoe said:
OK, it hit 98 here yesterday and I see what the complaint is about. Even under recirt and after 15 minutes of driving, when I would slow down, or sit still at a light the air would get warm. Felt like I was on vent. :( Now I can see why people are upset. Before now it has only got up to around 87 or so.
Jump on board with us pissed off sweaty hot people, MoJoe!! :laugh:
 
#41 ·
I found this while searching on the NHTSA site:

Technical Service Bulletins Summary

Make: ISUZU
Model: ASCENDER
Year: 2005
Type: MULTIPURPOSE PASSENGER VEHICLE
Service Bulletin Number: 0512001
NHTSA Item Number: 10014796
Summary Description:
INTERMITTENT A/C PERFORMANCE CONCERNS IN HIGH AMBIENT TEMPERATURES AND OR HIGH HUMIDITY CONDITIONS ESPECIALLY AT LOW ENGINE SPEEDS. *EH

Jeff
 
#42 ·
Same issue here in NJ

Same issue here guys with my 04 Trailblazer. It is 82 here in New Jersey and my air is blowing "OK". Not as cold as it should. Had it checked once. As you all have been told as well by your dealerships that everything checks OK. They placed the leak dye to be sure but do not see any issues.

My A/C starts off cool then seems to get cold for a few minutes (usually when I am on the way to the dealership again for them to see what is going on) and then it gets warmer.

I have been reading the GM bulliten everyone has refered to. It also states that even if they do this modification, it will only produce a 3% increase in performance. Not sure if it is even worth the effort.

I would like to hear from anyone that has had their dealership perform this fix to see if it realy improves the A/C or not.
 
#45 ·
Goin in too

I have just scheduled my TB to go in this Sat. The issue is when they usually check it, it is early on in the day so it is very cold. To them it is "what do you mean it is not cold...it is ice cold now...nothing is wrong"

Just drove home from work, about 80 again with high humidity and it was cool...not that hand numbing cold we are looking for. If i check it again in an hour os so, it will blow ice cold.

I mentioned the bulletin when I called to make the appointment. I did get a "it takes a while for the A/C to get cold in hot weather" response from the tech when I spoke with him. I am not buying it though. In my Wife's Nissan Maxima, you can hang meat in there after a few minutes of the A/C running!

I will let all you know how I make out this time around at the dealership....

Stay Tuned Kiddies!
 
#46 ·
A/C Update

Well all, came back from the dealership. I brought the bulliten with me as well to show the tech. They checked the software version on on my Trailblazer and sure enough it needed to be upgraded. As the tech was upgrading the software, we began to talk about this issue. He said that there are so many things that can cause this, it is really a "lets try this, lets try that". He felt that the softwate upgrade could help. However he did say that I shouldn't expect it to get cold enough to "hang meat" in the truck during very high teperature days. High humidity makes it worse.

After the upgrade, it did seem like the A/C got colder a bit faster at idle ( we sat in the car w/ a thermostat in the vent to monitor the temp as it got colder) It got a bit below 60. He said it should go down a dew more degrees when driving (with air going through the radiator).

So, there it is..I will keep an eye on it to see if this makes any difference. They also did mention that they have been experiencing some bad compressor switches with the Trailblazers as well (could be the issue if this software upgrade doesn't help)

Also they did thank me for alerting them about the bulliten (that was a first from any dealership I have ever been to!) Hope this helps anyone else that is going through the same issue.
 
#47 ·
I'm going to have my EXT V-8 looked at. I noticed poor AC performance at idle, especially in the back. I have also noticed that it works fine sitting still if I rev the engine to 1500rpm. It is in the 90s and very dry here. Temp gage goes up to about 2 marks past half way before it drops.

I noticed this after I spent 45 minutes in the vehicle waiting for my wife 2x.

I keep the temperture around 70 to stay comfortable. 70 in my Caddy would freeze something off your body once it cools down the interior.
 
#49 ·
lisicki said:
Well all, came back from the dealership. I brought the bulliten with me as well to show the tech. They checked the software version on on my Trailblazer and sure enough it needed to be upgraded. As the tech was upgrading the software, we began to talk about this issue. He said that there are so many things that can cause this, it is really a "lets try this, lets try that". He felt that the softwate upgrade could help. However he did say that I shouldn't expect it to get cold enough to "hang meat" in the truck during very high teperature days. High humidity makes it worse.

After the upgrade, it did seem like the A/C got colder a bit faster at idle ( we sat in the car w/ a thermostat in the vent to monitor the temp as it got colder) It got a bit below 60. He said it should go down a dew more degrees when driving (with air going through the radiator).

So, there it is..I will keep an eye on it to see if this makes any difference. They also did mention that they have been experiencing some bad compressor switches with the Trailblazers as well (could be the issue if this software upgrade doesn't help)

Also they did thank me for alerting them about the bulliten (that was a first from any dealership I have ever been to!) Hope this helps anyone else that is going through the same issue.

Interesting. May have to look into this. By the way, what year is your vehicle?
 
#50 ·
The wife and I were in Las Vegas the other day 114 degrees, in stop & go traffic A/C just didn't work well. As soon as we got up on the freeway the A/C worked great.
As a person who has an EPA Type I & 2 HAVC Certification I can share with you that R134A is not a good refrigerant in hot surroundings. this is why many manufactures use both mechanical & electric fans trying to keep as much air flowing over the condenser to cool it.

Just after 134A came out in refrigerators I got a warranty call from G.E. a lady had bought a band new upright freezer and it wasn't cooling. So I loaded it up took it back to the shop plugged it in and sitting in the middle of the shop it pulled down to -10 degrees in short order, as I was thinking about where it was located in the customers garage I realized that it was stuffed in a hole where her old R-12 freezer was, & GE had a warning label that said it needed to be in an open area. I took it back the next day and told her she couldn't put it in that hole, so she found another place to put it and that was the end of her problem and mine.
One thing you can do is set up a mister in front of the condenser use a windsheild washer pump to mist at stops. that will drop the temp with cold water about 15 degrees
 
#51 ·
Hmmmm: Deep Freezer + Trailblazer = No A/C problems... :laugh:

Seriously, thank you for the suggestion, but on a $30,000 truck, the last thing I want to hear from my dealer is that my A/C is at its best and can't cool when its hot out. :duh:

I am sure that there is somthing that my dealer can do about this problem, and I will be a frequent customer/complainer until like jauto98 said, they try everything!!
 
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