AC not cooling well at idle and in hot weather - want to add electronic co denser fan - 2008 H3 Alpha

[Jds]

I recently purchased a 2008 Hummer H3 Alpha with 250K miles in it from a friend.

AC is not cooling well. Live near Boerne, TX and we have had hot weather, close to 100 degrees.

I added R134 refrigerant and got pressures up, so cooling is better. Temp was about 110F in open garage. Then took outside to 98F ambient.
Adjusted high pressure refrigerant level to point where compressor would
Shut off from high pressure. I think this was at 450 psi. This gave me the best cooling.

I took my leaf blower and forced air through the condenser and high pressure went down to around 350psi.

Engine is not overheating. Air temp of radiator water is around 190F. Air running through ran and radiator is about 160F.

I think I need to add an electronic co denser fan.
I’m mainly driving on ranch at low speeds and idle much of the time.

I read in a previous post that there is a PCM
Option for electronic fan and then can add a 12” condenser fan in front of co denser.

I would appreciate some help on what to order and learn from other experience bs trial and error on my part.

It seems my fan clutch is working (I assume this because lots of air is
Moving and it doesn’t over heat). At idle on hot days the guage does read 1/4 way above midline on temp guage. I’m pretty certain I’m getting very high refrigerant line pressure because not enough cool air is passing over condenser.

Would appreciate advice.

Thanks, JD

 

[zebra]

i'd try cleaning first. used my air compressor & extendo wand to blow this out of ours last week - likely over a decade's worth of crap between the radiator & condensor. clutch fan works a lot less now.

 

[zebra]

PS: you have to blow from the engine bay forward... otherwise, you're just lodging everything further into the fins.

 

[Jeepwalker]

I completely agree. The condenser is the outside heat-exchanger for your tk's AC system. Probably years of debris and dead bugs between the fins. You might pull the radiator back, or try to split them apart a bit so you can be very thorough to clean the condenser. Preferrably from the backside. Try using some condenser cleaner HERE. It'll help break down bugs. Adding an E-fan will only block airflow.

If once you have the Condenser very clean it doesn't help, then it might be the time to consider taking it to an AC shop. Could be a number of other small things keeping it from cooling properly.

 

[alrock]

While the e-fan may block some airflow when not in use, it definitely increases airflow when in use. There's a reason GM had this as a factory option in South Africa and the Middle East. Reloader cobbled together the parts to put that system on his Alpha and it was effective.

Considering your situation of low speed driving and idling, I think an e-fan is a good solution. I would not recommend it most of the time, but your situation may call for it. My H3 only needed cooling help at stoplights as the mechanical fan could not keep up here in PHX in triple-digit temps. And that's with new fan clutch, newish condensor, newish radiator and a thorough cleaning. Still, start with the easy stuff like cleaning.

 

[rascole]

Agree with a deep clean first. Due to age, the overall system might be showing signs of normal wear and tear. Compressors do wear and leak back, condenser tubes plug up, filter plugged, drier... all these add up to poor performance. 16 years and 250k is a lot for any AC system in your environment.

 

[ski.dive]

You could be Low on freon.

 

[Jeepwalker]

Or too high.

 

[Jeepwalker]

There could be moisture in the system, pressure switch not working properly, weak compressor, piece of crap lodged in the screen, blend door not closing/sealing. Who knows what the previous owner, or his guru 'wonder-buddy' might have put in the AC system for refrigerant or extra oil or who knows what??? They might have added 'miracle refrigerant'. There's lots of reasons an AC system might not be blowing 'cold' air. I'd suck it all out of there and put it under a deep vacuum for a long time and start over. 100*F isn't that hot. It should cool fine. I've had mine in Moab when it was well over 100F and it cooled just fine, no extra fans.

Technically you're not 'blowing cold air'. It's helpful when working on an AC system to look at it like a temperature removal system. It's using Freon as the medium to remove the heat from the inside of the cabin and reject it at the condenser outside of the cabin. When you look at it that way, you can see why various factors might affect it's efficiency. There needs to be proper airflow on the inside evap side and condenser side. The refrigerant needs to be spot-on. Moisture in the system will ice-up inside. A pressure sw can affect cycling. A poor compressor wont produce enough pressure. I know you've checked a lot of things and seem to be doing a great job. Keep looking at things. W/o being there about the only thing a guy can do over the computer is lob out ideas.

Worst case you might take it to an AC shop and get a look-over & free estimate. Even if they charged you for a diagnosis it might be worth it. Then take it from there.

 

[Teahead]

350psi seems way high.

I would think 200 psi at the highest.

 

[alrock]

Put a thermometer in the air vent and drive around for a while at street/highway speeds and see that temp the air is. If it's in the 40s, maybe low 50s, I doubt it's an issue with the refrigerant as it would cooling effectively.

Often if we use those parts store a/c kits they can put in too much oil with the refrigerant and that throws off the efficiency.

 

[cgalpha08]

i would pull the condensor and give it a good cleaning between it and the radiator. or even swap in a new condensor. Crud gets between the two and can cause cooling issues for both the AC and the engine due to build up.
Did you use a gauge set that hooks up to both the high and low side? the auto part store cans dont and dont really do a good job at getting the pressures right. They have the kits on amazon and harbor freight for cheap