08 H3 Alpha HVAC Info:

[Best4x4]

Okay so after my horrible 10hr trip back and forth from San Antonio, TX with my Efan not keeping my rig cooled down my HVAC may have taken some damage. I found small traces of freon around the hi/lo inlets. Now my HVAC will start to freeze over. It will completely stop dripping, and eventually if you drive long enough airflow thru the vents gets restricted. My only guess is because it is freezing up at the evap core blocking the airflow. If I switch over to heat water will just start gushing out. I'm thinking I am slightly low on freon. It's extremely cold until it starts blocking airflow.

I borrowed a friends gauges and I got these results.

Static PSI with engine off: 27
High side: 35 went to 57lb
Low side: 20+ then 0

My sticker on the airbox is long gone so I have no reference points. From what I can tell the expansion valve is working, which leads me to low freon. None of the hoses have residue on them besides the few drops of freon I found near the inlet valves.


Any help would be great as I am not an HVAC Tech lol.

 

[CaseyS]

I'm no A/C expert but sounds like you are either low on freon, or you have something going on with the compressor.

 

[Best4x4]

Compressor is working good, but I think the entire system got stressed out running 231-234 for 5Hr and then 224-229 for another 5Hr... Gonna have to find someone with their airbox sticker intact for an Alpha.

 

[SuperBuickGuy]

it sounds like your over-pressure sensor isn't working. The biggest issue with electric fans is, in the aftermarket, it's devilishly hard to get a fan that is adequate for the vehicle. Engine-driven fans generally pull 2x-3x more air than electric fans of the same size (which make sense because electric fans can spin up to 1200 rpm, whereas the engine fan can spin even more than engine rpms).

 

[Best4x4]

Yeah I've gotta find someone I trust to look at it.

 

[SuperBuickGuy]

Yeah I've gotta find someone I trust to look at it.

good luck, it took me quite awhile to find a good mechanic. I do most of the stuff myself, but there are somethings I don't have the tools for, or I'm on injured reserve and can't do, or I'm stuck with a case of idontwannaitis

 

[Best4x4]

Yep A/C isn't really my thing. Gauges and a vacuum are all I have available.

 

[CaseyS]

If you are driving down the interstate, you shouldn't even need a fan. Running hot would have happened sitting in traffic in upper 90 degree weather with the A/C on high. Is something blocking your radiator? Checked the thermostat lately?

I seem to argee, the high pressure switch failed and you popped the relief valve somehow.

 

[Best4x4]

Sitting was the only time the efan could keep the engine cool. Higher RPM's and cruising down the road at 70-80MPH the efan couldn't move anymore air thru the radiator. It never runs hot around town or sitting. Efan or Clutch Fan. It only got hot on hills, higher speeds or upon passing with the efan. Removing the lower skid or stopping and raising the hood was the only way the efan could try and keep up. The efan basically was at it's max and once past it, the engine couldn't cool down.

The thermostat is working, and I even removed my front license plate on my arb to allow more air flow. The problem I see is the efan didn't fully cover the radiator. It is mounted slighltly off center due to the waterpump pulley so IMHO that's creating a hot spot that isn't near where the efan was sucking air thru the condensor/radiator. The OEM setup is centered and it allows airflow thru the entire condensor/radiator surface.

This is the first summer with the efan vs OEM setup and it flat out failed. Now an extra efan along with the clutch fan would be nice, but the summer before the efan = no overheating.

I agree I think the stress of 234-237F made my A/C blow out some freon. The compressor would turn off, but my wife and I were hot... So we would turn it off/on and of coarse it would run a while then freeze back up. From what I read if the condensor doesn't get enough airflow to cool down the system will freeze up, which it did, but eventually it let out some freon and now that I am back to normal temps it's freezing up due to low freon vs the overheating issue.

I never got any DIC's on low HP, overheating, or HVAC warnings. I did my best to keep things under control but out in the middle of nowhere I really had no choice.

 

[CaseyS]

Do you have some pics of your fan and bumper setup? When going down the interstate, the oncoming air should be forced through the radiator stack. Are all the side baffles in place between the grill and the A/C condenser to direct the oncoming air through the radiator? Once the air is in the engine bay it has to exhaust down around the engine and under the truck. Have you done anything else under to impede airflow out of the engine bay? Do you have too much stuff on your bumper in the way of getting air into the grille at highway speeds?

Obviously I have a different setup than everyone else, but I still haven't gotten around to installing my fan. Idling in traffic the temps creep up towards the 3/4 mark but once I get moving they come right back down a little over 1/2 gauge. (I still don't have the A/C hooked back up yet, that will definitely require getting a fan of some sort running).

 

[Best4x4]

Last summer with the OEM Clutch Fan setup the most I ever saw the gauge climb was to between 1/2 and 3/4. This summer with the "performance" efan I was at 3/4 and just above..... No other mods were done during that time. The H3 Alpha has always had an ARB and winch on it.

Yesterday I completely removed the "performance" efan kit and went back to the stock setup. At idle it is 191 vs 193 with the efan. Then in traffic it will get up around 204F then you can feel the fan clutch engage and the temps drop. At speed I'm no longer having an issue. I will do more test over the weekend, but engine cooling is back to normal.

It's the HVAC that needs some attention either due to low freon now or damaged equipment from the major stress test it was put through. I am highly disappointed in the efan. Noise didn't bother me, but watching the temps climb and climb without being able to do anything to fix it is what ticked me off, and now HVAC issues after the fact...

Great product for Oregon, Canada, Washington, but no way does it work in TX!!!

 

[Woodtick]

I do HVAC for a living,by no means a auto a/c expert. Someone already posted a p/t chart,this will help you add gas. There are only a few reasons a evap will ice up. Low on charge,lack of airflow across the evap, something wrong with the metering device. It sounds like its low on gas. You should also have 20 deg differential across the evap with the fan on high. If you still think it has to do with a over heating problem. Run the truck in the driveway with a garden hose on the condenser. I would bet the compressor cycles on low pressure,because it's low on gas. It wouldn't ice if it were very low on charge. It probably just needs to be topped off.

 

[Best4x4]

Yep exactly my thoughts Wood, just gotta find an honest person to add it. Chart is great but greek to me lol.

 

[Woodtick]

We have aprox 80 trucks in our HVAC service company. Other than a simple quick a/c repair,they take them to the dealer. If that helps you decide where to take it.

 

[rsc]

I looked up the weather last week in Houston and SA, said 92-93 degrees? That shouldn't overload the e-fan like that at 92, but with the Hummer's barn-door aerodynamics driving down the highway at 70 is like dragracing uphill with a boat in tow on any other vehicle. Going faster doesn't help, it just makes more heat. I know my I5 ran 215F at 75 last year when it was 98-100 out.

I used to service a/c systems on aircraft, I hated it. Its simple enough, I just never had the "touch" to get the last couple of degrees out of them.

 

[Best4x4]

I am done...... Friend suggested looking at my wifes H3 to see the gauges.... Took the high side valve off the inlet and now it isn't sealing.....

When it rains it pours... Make that two hummers down with hvac issues.... :roll:

 

[Woodtick]

That's why there is a o ring in the cap,give the cap a good snug.

 

[Best4x4]

Wife's H3 sealed up after a few drive cycles. My Alpha is still having issues after the 10hr 237F drive. It isn't low on freon, but after a 30-60min drive the blower starts barely blowing and you can faintly hear dripping. The Evap core keeps freezing up. If you run the fresh air intake vs recirculate and you run the heater for a few minutes it'll melt enough ice off the Evap that it will cool again, but I'm no longer going to use the HVAC until I get it looked at because I don't want to damage the compressor.

PCM of NC should pay for my HVAC repairs IMHO.