Is it normal for temps to rise during a long idle?

[rockola1971]

I also believe that the higher the humidity, the harder the system works to keep up with keeping the inside cooler. High desert temps are easier on the system than high humidity temps in say....Louisiana. Correct?

Yes, correct. Humidity carries heat. All air conditioners are dehumidifiers. Your refrigerator, deep freezer, central air, auto ac, window ac, etc.....all dehumidifiers. Thats how A/C removes heat by evaporating it on the evaporator. The refrigerant absorbs the heat to be carried out to your condenser and the humidity (water) is drained from below your evaporator. On a automobile thats why there is a water puddle below your vehicle when the a/c is on. In your home central air thats why there is a water drain line running to a drain, drain pipe, etc from the bottom side of your evaporator. In your fridge and deep freezer the humidity is recycled to your condenser via a drain pan that your condenser coil bottom side sits in and is actually used to lower the temp (pressure) of the high side in your condenser which actually makes it more efficient. This would be the same as you going outside to your home central air condenser unit and spraying it with cold water out of your garden hose. Remember the lower the outside temp the colder your vent temps(supply air) will be. This is because the condenser is cooled by the outside air and by adding cold water from the garden hose across the condenser coils will cause the refrigerant to reject more heat readily to the atmosphere and lower the pressure of the condenser refrigerant that is on its way back to the evaporator after passing through the condenser coil. The lower the high side pressure becomes before it gets to the evaporator the lower the temp of supply air will be.

 

[mattbta]

In Texas, in home AC during the summer, the business calls it "making water".

 

[afpj]

02 Yukon 4x4 ff. 118 today on pavement, high desert southwest. After fully warmed up, backed up at a light down the road , Idle for 5 minutes and coolant temp via torque pro hit 215 before the light turn green & off I went. The temp gauge on the instrument cluster doesn't go up above 205 ish. Just left the AC on 80 and the AC was cooling pretty nicely even at idle. Have a heavy duty fan clutch. It was whirring like a big rig when I hit the gas. Thankfully, AC was performing much better than 118 - 20 which equals 98°. Well, at least it felt that way.

 

[blueinkd]

My truck idles for long periods daily during this texas heat and no changes on temp at idle. I will sit in a spot close to an hour idling and both front/rear ac going. I do have new AC Delco water, pump, radiator, thermostat, 50/50 dexcool mix and all new hoses under the hood. Been 100* degrees outside this month. I can definitely hear the EFan on high speed as well at times.

After driving for for about 30 mins or so, the AC will keep nicely cold even when I park and idle. Mind you recirculation mode has to be on as well to allow the already cooler air inside the cab to flow past the evap core. No sense in continuing to cool down the outside air

 

[Rocket Man]

The ac in these trucks tends to not be so cold if you do much idling in real hot weather, e-fans or clutch fans. The engine temp shouldn’t rise though, at least mine never does but I did the e-fan conversion on my 02 so yours may be different with the clutch.

 

[Doubeleive]

I am on the other side with this when I had my 00 5.3 with a fan clutch as long as everything was good I could idle for hours in 115 deg ac on, temp never budged
I had that vehicle for almost 14 years, when the temp would start to climb it was because of the radiator, put in a new radiator and back to normal
so what I started doing was a annual flush with citric acid, this kept the system clean and flowing good.
my speculation with your issue is the fan clutch is not working properly or the radiator does not have good flow, regardless of age.
my 2012 does not budge either, it can idle all day ac cranked, 100+

 

[rockola1971]

02 Yukon 4x4 ff. 118 today on pavement, high desert southwest. After fully warmed up, backed up at a light down the road , Idle for 5 minutes and coolant temp via torque pro hit 215 before the light turn green & off I went. The temp gauge on the instrument cluster doesn't go up above 205 ish. Just left the AC on 80 and the AC was cooling pretty nicely even at idle. Have a heavy duty fan clutch. It was whirring like a big rig when I hit the gas. Thankfully, AC was performing much better than 118 - 20 which equals 98°. Well, at least it felt that way.

The temperature Delta is atleast 20deg. Usually is it is much closer to 40deg unless refrigerant is low (leak), condenser is dirty as heck or something else wrong in the system.

 

[afpj]

When you guys are saying the coolant temp never budges sitting at idle, are you referring to the coolant temp on the cluster gauge or an independent source like torque pro or Scan gauge? My cluster gauge doesn't ever budge above 205 warmed up... just under the 210 mark, Even when torque pro was reading 215.

 

[Rocket Man]

When you guys are saying the coolant temp never budges sitting at idle, are you referring to the coolant temp on the cluster gauge or an independent source like torque pro or Scan gauge? My cluster gauge doesn't ever budge above 205 warmed up... just under the 210 mark, Even when torque pro was reading 215.

I mean, you’re talking a 5-7 degree difference? I just use the cluster gauge. It’s fine as far as comparing how hot the engine is on a cool day as opposed to a hot day. It might not be perfectly accurate but we are talking comparison from one day to another. I have seen my engine get hot -and it definitely registered on the gauge- when it’s lost coolant so I know it does work.

 

[Electrician]

To help put it in perspective: Im using an OBDLink mx+ with their app linked to my head unit so I can read all my sensors basically. Including air intake temperature, which I keep a gauge for on my screen to monitor. Left my house the other morning: 85 degrees air intake temp cruising 60mph. Bit later... get to a long traffic light, a/c running... temps climbing to 130! A few days ago, 2:30ish in the afternoon, got in my truck to leave work, started up to cool me off, few minutes air intake temp was 190!!!
Doesn't take long at all for your engine to start sucking in oven hot air when you sit