AC effectivness at idle

[hammerheadfistpunch]

Couldn't find any info regarding how the AC is supposed to behave at idle. Backstory, I bought my 97 long distance and the PO had recently replaced the compressor with another cheaper brand, probably just a reman. Anyway, it cools just fine so long as the engine revs are above 1200. i.e. sitting at a light doesn't produce much cold. My suspicious are that it was installed improperly and has too little (or more likely too much) refrigerant. Its not gotten worse in the 3 years I've owned it. Anyone have any experience with this issue? Refrigerant maybe, or just the remaned part?

 

[Hornd]

Have a shop hook up the gauges and check the low pressure side.
I assume you can see coolant in the sight glass on the fender?

 

[slow95z]

it was 102 and 80% or better humidity last week and my AC was blowing little bits of ice out of the vents. something is wrong with yours.

 

[george_tlc]

Assuming your cooling system is working well then nice cold air should come out even at idle.

Doesn't hurt to stick an obd2 reader in and observe actually engine coolant temperatures...

With all the recent A/C threads I guess summer must be in full swing in some areas of the country

cheers,
george.

 

[danthman114]

how hot is the engine running? try a new fan clutch or replace the fluid to 20k. you can also look into threads on electric fans. youre not the only one having the same issue.

 

[vegastoy]

On mine you can hear the compressor cycling on and off at a stop light (cycling on and off on high pressure I suspect). When it's on or your moving it blows ice cubes. I suspected the fan clutch since I could spin it very freely when the engine was off. I replaced the fluid with 20K and the cycling is less frequent but it still does it. I'm going to pull the fan clutch off again and try adding a little more fluid. I would check your fan clutch first, there's a lot of fan clutch threads on here. Seems to be a common issue...

 

[inkpot]

Adding fluid to your clutch is not the same as raising the viscosity(CST) rating. Overfilling can be a problem.

Generally speaking, this is why a lot of us add the pusher fan. They help some at low RPM and slow ground speed.

 

[hammerheadfistpunch]

I can hear the compressor cycling and the cooling system is in great shape (completely new cooling system shortly after I bought it including new blue hub fan, radiator, pump, etc). It blows cold when moving, only when idling where it starts to do poorly. I can rev up to 1200 and it will start to cool again just fine.

 

[Dave 2000]

Either your fan is not pulling enough air at idle or your low on refrigerant, the condenser is blocked, or possible but unlikely, the replacement compressor does not have enough capacity for the vehicle system.

regards

Dave

 

[TexasJack]

I live in Texas. If it is over 100 and sunny, your AC will not cool the truck adequately unless you are going 70 MPH. Below 95 it will work reasonably well. Mine has always been like that and I have owned it since 97. All of the parts have been changed out since then so that is how it works. Trying to wheel your truck over really rough terrain during the dead of summer in Texas is not fun as you will sweat your ass off.

 

[hammerheadfistpunch]

I live in Texas. If it is over 100 and sunny, your AC will not cool the truck adequately unless you are going 70 MPH. Below 95 it will work reasonably well. Mine has always been like that and I have owned it since 97. All of the parts have been changed out since then so that is how it works. Trying to wheel your truck over really rough terrain during the dead of summer in Texas is not fun as you will sweat your ass off.

Yeah, I realize that these trucks are not effective in terms of AC performance (lots of waste heat, lots of glass, lots of car, etc) but this is oddly specific. Granted its been 99 here lately so that certainly plays a roll, in terms of performance or perception of performance but aside from that its definitely specific to low engine speed. I mean, I could use my hand throttle to up the idle to 1200 and get cool, but at 750 its just not cold. Im going to have someone check the coolant pressure and see where its at.

 

[Flank]

Trying to wheel your truck over really rough terrain during the dead of summer in Texas is not fun as you will sweat your ass off.

It will, however beat the hell out of being in an open top 40 while you have your AC on and the kids strapped securely in the back! That is, until you seize your compressor 10 minutes after entering the trail while it is 105* out and the AC belt shreds. Ask me how I know...
That particular wheeling trip and subsequent 45 minute drive home was a particular joy with kids complaining about being hot.

 

[1972FJ55]

I'd suspect the fan clutch but I'd also make sure the surface of the condenser is clean and nothing obstructing it.

 

[LouisianaRubicon]

Mine started doing the same thing a few weeks ago. I found a thread where someone had the same issue and he added refrigerant with a store bought recharge kit and it fixed the issue. Report back with what you find. I really enjoy your content on overland & expedition by the way @hammerheadfistpunch

 

[hammerheadfistpunch]

Mine started doing the same thing a few weeks ago. I found a thread where someone had the same issue and he added refrigerant with a store bought recharge kit and it fixed the issue. Report back with what you find. I really enjoy your content on overland & expedition by the way @hammerheadfistpunch

Yeah, I suspect refrigerant levels too, I will have to get it checked out. Thanks for reading on o&e, I know I'm like the billionth blog on the topic but it's a good group of interesting people that make this one cool, imo.

 

[TexasJack]

Please post up what you find. I have replaced my fan clutch with the "blue" fan clutch and had my air conditioner worked on many times over the year. I would love to find a way to get it to keep me cool during the summer! As it is, I park it in the garage in mid-June and it sits there until October unless I drive it at night.

 

[Dave 2000]

Interesting how my all electric system is waaaay more efficient than the stock units, in particular when going slow or idling.

regards

Dave

 

[TexasJack]

Interesting how my all electric system is waaaay more efficient than the stock units, in particular when going slow or idling.

regards

Dave

Knowledge is power. In your case it is a cooler vehicle! I eyed your post carefully. I intend to recheck everything. Sweating your ass off in a really hot truck is NO FUN!

 

[RedJed78]

Adding fluid to your clutch is not the same as raising the viscosity(CST) rating. Overfilling can be a problem.

Generally speaking, this is why a lot of us add the pusher fan. They help some at low RPM and slow ground speed.

would the adding of an electric fan solve this problem?

 

[Dimples]

I was having a similar issue in Phoenix AZ and the system was just low on freon. It had a R134a conversion when temps were cooler so the system didn't cycle enough to get full. Was almost running a vacuum on the low side at 115 ambient air temp. Half a pound of refrigerant and the truck is much more comfortable even at idle.