Do lower temperature thermostats create issues in DI engines?

[Dozerboy]

I have my 2022 6.6l gasser that I really like for work. The AC "sucks" though. It probably needs a new compressor because I've heard of plenty of issues with them. However I'm to stubborn to spend $2000 on something I don't have confidence in will fix my issue. The AC works okay other than I idle a lot. 10hrs a day sometimes in 100* weather and high humidity. I feel like the biggest issue is the condenser is getting heat soaked and the AC this doesn't function very well. I cleaned the cooling stack and that helped. The AC doesn't seem to get much over 60* now when it would hit 80* before. I'm kind of wanting to change the thermostat for like a 180° one. I've noticed the AC starts going downhill when the the engine starts getting heat soaked and the intake temperatures climb up over a 180°. My other option is to add an electric pusher fan in front of the condenser. Hopefully not needing 2. I like the thermostat idea better because I feel like it's a little bit more foolproof than adding an electric fan.

Thoughts? Dropping the engine temperature 20* has me a little concerned since it's a DI engine and these trucks are so complex. I don't want to make another issue.

 

[Ridin'GMC]

To make the AC efficient, the condenser needs to cool down by having air flow to cool the condenser. Idling will just create heat soak because there's no airflow to cool. Spraying water on the condenser helps to cool. Lower thermostat doesn't do anything, it just opens the thermostat at a lower temperature but it still can run hot at idle.

 

[Dozerboy]

I'm hoping a lower Tstat will reduce the heat soaked of the condenser. I've never had a truck that run as hot as these trucks do. The engine temperature is always 200* to 205*. Even if the thermostat doesn't necessarily cure the issue I'm hoping it'll cool off the truck some. Everything on the front is blistering hot all the time.
I've had lots of trucks and Rams are the only ones I've had this problem with the AC. It was easy on them just to put them in high idle though.

 

[2004LB7]

I don't think it will help your situation. The engine is what's creating the heat. So, if the radiator is heat soaked and running hot, having the thermostats open at a lower temp will only bring in more heat from the engine to the radiator. In all likelihood the thermostats you have in there now are already open when it's running hot like you describe.

A pusher fan is probably the only real viable option.

Have you tried opening the hood when idling for extended duration to see if it helps?

Another issue with running the AC during idle, along with the higher temperature and lack of airflow is the lower compressor speed. Lower pressure or refrigerant flow as a result. This along with the faster engine fan speed is why high idle helps so much with AC temperature

 

[Dozerboy]

Lower Tstat bringing more heat to the stack.... I didn't think about it that way.

That's a good idea opening the hood.

1 pusher fan I don't mind 2 is starting to to get expensive as a test.

 

[Chevy1925]

Fyi, there is a tsb to change the expansion valve out to a newer one. Iirc the updated valve is for 1234yf strangely enough.

Anyhow, ill see if i can find it. Not 100% it will fix your issue as the compressors in those trucks fail alot but the expansion valve we put in a 2021 seemed to have made a decent difference

 

[2004LB7]

Fyi, there is a tsb to change the expansion valve out to a newer one. Iirc the updated valve is for 1234yf strangely enough.

Anyhow, ill see if i can find it. Not 100% it will fix your issue as the compressors in those trucks fail alot but the expansion valve we put in a 2021 seemed to have made a decent difference

The pressure temperature curve for 1234yf and 134a are very close. Not surprised it would work

 

[Chevy1925]

Here it is

View attachment Tsb 24-na-183.pdf

 

[jlawles2]

I wonder if you are having electric fan clutch issues?

When the truck is idling for long periods of time, try propping the hood open slightly to allow for more air to escape from under the hood?

Is there any way to do the high idle option on a gasser? Increasing air flow and slightly elevating the RPM will also help lower engine temps as the engine is not "lugging" under load. IIRC the AC compressor is about 20 HP, and the cooling fan is probably that or better at full lock. Elevating idle will bring the engine power up slighly helping.

 

[Mikey52]

And remember the in dash gauge is a dumb gauge. It maybe reading 205 but a scanner will probably read about 185.

 

[Dozerboy]

I wonder if you are having electric fan clutch issues?

When the truck is idling for long periods of time, try propping the hood open slightly to allow for more air to escape from under the hood?

Is there any way to do the high idle option on a gasser? Increasing air flow and slightly elevating the RPM will also help lower engine temps as the engine is not "lugging" under load. IIRC the AC compressor is about 20 HP, and the cooling fan is probably that or better at full lock. Elevating idle will bring the engine power up slighly helping.

Those are thinks I'm going to look at aswell. Thanks

 

[Dozerboy]

And remember the in dash gauge is a dumb gauge. It maybe reading 205 but a scanner will probably read about 185.

I was hoping that was the case but I verified it with a scanner. It's kind of how I determined the issue is heat soak. Soon as the intake temperatures hit around a 185* when the AC starts giving up