AC not blowing cold at idle

[slypher25aussie]

I’ve noticed at stop lights and idle that my AC is barely cold. Once I get the engine going, it’s nice and cold.

I’ve read conflicting info that the condenser isn’t getting the airflow it needs so it’s not effective at idle. Or it needs a recharge. Or it’s overcharged.

Anyone else experience this?

 

[OR VietVet]

IMO, it does sound like it is undercharged. You may also have a problem with the a/c condenser. At speed the air flow is ok at the condenser and at idle the air flow is way down and does not dissipate the heat at the condenser as well. There was some years of condenser problems but would have to check for the effected years. Is the condenser on either the Yukon or Suburban the original one? Care to share which rig has the problem? Is it a secret?

 

[Tonyv__]

My 2000 Tahoe that I sold a few months ago had this same exact problem. Kid I sold it to took it straight to a mechanic and said it had a tiny leak and was low on Freon. They fixed it and charged it up and it apparently worked great after that

 

[Tonyrodz]

Do you have a clutch fan or electric fans?

 

[slypher25aussie]

IMO, it does sound like it is undercharged. You may also have a problem with the a/c condenser. At speed the air flow is ok at the condenser and at idle the air flow is way down and does not dissipate the heat at the condenser as well. There was some years of condenser problems but would have to check for the effected years. Is the condenser on either the Yukon or Suburban the original one? Care to share which rig has the problem? Is it a secret?

Oops I forgot I still had the Suburban on my sig... sold it a few weeks ago so gotta take that off. This is the Denali I’m referring to.

Here’s some more interesting info... I found a hose and gauge I had from one of those refill it yourself Freon cans and the gauge says it’s overcharged by about 30psi. Does that seem right? I thought if it was overcharged, it wouldn’t work at all.

 

[slypher25aussie]

Do you have a clutch fan or electric fans?

Clutch

 

[Tonyrodz]

Clutch

I've read clutch fans aren't that great in the cooling dept if you're sitting still. Electric fans cool great once they kick in while idling.

 

[ks03]

I've read clutch fans aren't that great in the cooling dept if you're sitting still. Electric fans cool great once they kick in while idling.

I’ve done it, made all the difference sitting at idle

 

[slypher25aussie]

I’ve done it, made all the difference sitting at idle

So you had the same mediocre cooling when idling with your clutch fan?

 

[OR VietVet]

It is going to depend how quick the fan clutch reacts to the lack of air across the condenser. I agree that the fan clutch/fans need to work correctly to help the a/c work at idle but his share of a reading is of no help. Need a set of gauges hooked up and post what the high and low side readings are at idle and is the clutch cycling.