Engine over heating with AC on at low speeds

[afpj]

You put NON Dexcool anitfreeze in? I cannot recall specific posts but that alone might lead to bad things happening...perhaps it was in the long term but I thought I read Dexcool had certain chemicals in it that others didn't for these GM's. Curious as to why you didn't use dexcool?

 

[BRUTUS_T_HOG]

Did you put straight antifreeze or was it 50/50 premix? Using pure antifreeze will cause overheating.

When its running hot is the fan moving a lot of air through the radiator and is it hot air? It should be moving a lot of hot air. New does not mean good when it comes to your fan clutch.

Another thing, if you increase the engine RPM's a little does it cool down?

---------- Post added at 11:41 PM ---------- Previous post was at 11:37 PM ----------

You put NON Dexcool anitfreeze in? I cannot recall specific posts but that alone might lead to bad things happening...perhaps it was in the long term but I thought I read Dexcool had certain chemicals in it that others didn't for these GM's. Curious as to why you didn't use dexcool?

Dex-cool vehicles can safely be converted back, though I personally like to use what the manufacturer designed their product to use.

Dex-cool is silicate and phosphate free to prolong water pump seal life, reduce corrosion, and be more compatible with the increasing amount of aluminum parts used in cooling systems.

 

[92__silverado]

Did you put straight antifreeze or was it 50/50 premix? Using pure antifreeze will cause overheating.
50/50 mix

When its running hot is the fan moving a lot of air through the radiator and is it hot air? It should be moving a lot of hot air. New does not mean good when it comes to your fan clutch.




---------- Post added at 11:41 PM ---------- Previous post was at 11:37 PM ----------



Dex-cool vehicles can safely be converted back, though I personally like to use what the manufacturer designed their product to use.

Dex-cool is silicate and phosphate free to prolong water pump seal life, reduce corrosion, and be more compatible with the increasing amount of aluminum parts used in cooling systems.

The fan seems to be moving a lot of hot air when its hot.

Another thing, if you increase the engine RPM's a little does it cool down?
Today after running the AC and getting up to about 220 i turned off the AC and increased RPM. The temp never went down, after about 5 minutes, I turned the heat on.

If finally started to drop after 4 or 5 minutes. it dropped to about 210, then hung there, then dropped below 210. When the temp drops it isn't gradual. it drops in 5-10 degree increments it seems, for what that is worth.

You put NON Dexcool anitfreeze in? I cannot recall specific posts but that alone might lead to bad things happening...perhaps it was in the long term but I thought I read Dexcool had certain chemicals in it that others didn't for these GM's. Curious as to why you didn't use dexcool?

Yes flushed out all the dexcool and changed over to regular green.

 

[BRUTUS_T_HOG]

I just went back and read that you are seeing 90 degree days. With it being 90 ambient temperature it sounds normal to be seeing 210-220.

190-210 is normal op. temp and running the AC puts more load on the system because it adds heat to the air traveling across the radiator

 

[92__silverado]

I just went back and read that you are seeing 90 degree days. With it being 90 ambient temperature it sounds normal to be seeing 210-220.

190-210 is normal op. temp and running the AC puts more load on the system because it adds heat to the air traveling across the radiator

190-210 might be normal, but 230-250 is not. Putting a radiator in since everything else has been replaced.

 

[BRUTUS_T_HOG]

Yeah 250 is way too high I would say 230 MAX.

Being 90 outside though puts a heavy load on the cooling system. I think you probably do have a partially plugged radiator. Let us know how it goes

 

[Yukonboy2014]

Idling in 110* heat today (no Joke--South Tx), AC on full, my '01 Yukon did creep up to 220-230 before I realized it was escalating, so I revved the motor up a bit to get some air moving over the radiator. I guess the mechanical fan just can't move enough air at 500 rpm idle to keep up with the heat load. I'm looking around to fashion a sort of high-idle switch to keep air moving when idling in the heat.

 

[sparkvark]

I had the same problem with my 01 Yukon XL. I replaced the fan clutch and the problem went away.