Realistic AC expectations please

[desertwampa]

97 Lx450. Just like every new owner, I've been knocking out items since I bought it. Chased down an overheating issue. Which seems to have worked for the most part.
-brand new fan clutch modded by red line cruisers
- brand new aluminum Kyoto radiator
- New hoses off the radiator
- new AC compressor
- new ac coolant charge
- 100 series aux/elec fan installed

This question i have is should I expect my AC to stay cool on this old truck when outside temps are 100+ and I'm idling?

When I'm moving and outside teams are below 100, AC works pretty damn well. But when I have to wait in afternoon line to pick up my son from school and temps are 100+, the AC just can't keep up. This causes my coolant temp.tp slowly rise to 200-210..

Am I crazy to expect the AC to be able to consistely stay cool under these circumstances?? If I'm not crazy, what else can I do besides what's listed above?? Should I have more ac charging done?

 

[uscmas412]

97 Lx450. Just like every new owner, I've been knocking out items since I bought it. Chased down an overheating issue. Which seems to have worked for the most part.
-brand new fan clutch modded by red line cruisers
- brand new aluminum Kyoto radiator
- New hoses off the radiator
- new AC compressor
- new ac coolant charge
- 100 series aux/elec fan installed

This question i have is should I expect my AC to stay cool on this old truck when outside temps are 100+ and I'm idling?

When I'm moving and outside teams are below 100, AC works pretty damn well. But when I have to wait in afternoon line to pick up my son from school and temps are 100+, the AC just can't keep up. This causes my coolant temp.tp slowly rise to 200-210..

Am I crazy to expect the AC to be able to consistely stay cool under these circumstances?? If I'm not crazy, what else can I do besides what's listed above?? Should I have more ac charging done?

You need the Nissens condenser from Rock Auto. It was a game changer for me. I rarely leave my fan on high anymore, even in the FL heat.

Also make sure the systems is evacuated and charged properly.

 

[manofthewoods]

97 Lx450. Just like every new owner, I've been knocking out items since I bought it. Chased down an overheating issue. Which seems to have worked for the most part.
-brand new fan clutch modded by red line cruisers
- brand new aluminum Kyoto radiator
- New hoses off the radiator
- new AC compressor
- new ac coolant charge
- 100 series aux/elec fan installed

This question i have is should I expect my AC to stay cool on this old truck when outside temps are 100+ and I'm idling?

When I'm moving and outside teams are below 100, AC works pretty damn well. But when I have to wait in afternoon line to pick up my son from school and temps are 100+, the AC just can't keep up. This causes my coolant temp.tp slowly rise to 200-210..

Am I crazy to expect the AC to be able to consistely stay cool under these circumstances?? If I'm not crazy, what else can I do besides what's listed above?? Should I have more ac charging done?

I have found that idling in neutral (or park) increases the RPMs enough to make a little difference. Worth a try, doesn't cost much.

 

[oilbrnr]

What is the temp out of the vent to the right of the gauge cluster? I get 39-40* at idle with outside temps above 100 here in Phx. This is with a mod'd ToolsRUs clutch and a JDM aux fan triggered off the intermediate switch. Scanguage around town coolant temps this time of year down here, 187-191*

 

[greentruck]

39 to 40 degrees out of the vent sounds pretty good for R134a.

 

[KYLXFJ]

As stated, id start with measuring your temp split from ambient air in cabin to air discharging from vent. Then the only question is if its moving enough air. After replacing my condenser, line set, etc, I installed ceramic tint on all windows, but opted for essentially no "visible" tint, and the rig appears stock yet stays dramatically cooler inside than before. If the issue is more directed at engine temps, I had decent luck running a special coolant from Jegs, designed to lower temps, years ago on a 454 small block build that I struggled find a good temp sweet spot on. Best of luck.

 

[bicycleagent003]

Related but not A/C specific, I recently had ceramic tint installed on my 80 and now the A/C feels like I'm in a freezer. It's amazing how much the sun is heating up the air in our rigs, we have a lot of window surface area for the sun to drill through. I haven't put the fan speed in my rig above the lowest setting since I installed the ceramic tint, it's remarkable. I tinted the windshield and all four doors, and it made a huge difference. I had regular tint on the two front doors only, so I had that pulled off when I went to the ceramic. I live in sunny SoCal, and I wish I had done this ten years ago.

 

[thedoughboy]

I had similar issues with a heat soaked engine. I installed an auxillary fan in front of the condensor and it solved my problem.

 

[Marvelicious]

Related but not A/C specific, I recently had ceramic tint installed on my 80 and now the A/C feels like I'm in a freezer. It's amazing how much the sun is heating up the air in our rigs, we have a lot of window surface area for the sun to drill through. I haven't put the fan speed in my rig above the lowest setting since I installed the ceramic tint, it's remarkable. I tinted the windshield and all four doors, and it made a huge difference. I had regular tint on the two front doors only, so I had that pulled off when I went to the ceramic. I live in sunny SoCal, and I wish I had done this ten years ago.

I'm planning on doing this before next summer. One of those stupid-hot days this summer I was noticing what a difference it makes instantly when I drive into the shade. These rigs have a ton of window and it's basically like driving around in a greenhouse. The AC keeps up just fine with ambient heat, keep the heat out and you make your life more pleasant.

 

[chap79]

Temps rising to 210 at idle in 100* weather is a little excessive. How old is your water pump and thermostat? Reading the Red Line page about the fan I’m curious how much cSt and what weight they went with.

 

[mudgudgeon]

But when I have to wait in afternoon line to pick up my son from school and temps are 100+, the AC just can't keep up. This causes my coolant temp.tp slowly rise to 200-210..

In my experience, once AC is running cool in these sort of temps, it should keep up and you shouldn't see engine temp rising.

In Aussie summers it's regulary around 100⁰f+, and a cruiser parked in the sun should be cool inside after 10-15 minutes running, then it should stay cool.

 

[Saito]

As stated, id start with measuring your temp split from ambient air in cabin to air discharging from vent. Then the only question is if its moving enough air. After replacing my condenser, line set, etc, I installed ceramic tint on all windows, but opted for essentially no "visible" tint, and the rig appears stock yet stays dramatically cooler inside than before. If the issue is more directed at engine temps, I had decent luck running a special coolant from Jegs, designed to lower temps, years ago on a 454 small block build that I struggled find a good temp sweet spot on. Best of luck.

A 454 small block ? Like, a World block and a 4” stroke crank ? Do tell. I’m curious. Know it’s possible($$$) but not common. Very niche . . .and in your 80 ?

 

[Vasiliy]

Check the pressure on the line when it starts to cool worse.
Then I would check the evaporator(dirt's) and expansion valve
In my exp
After replacing engine radiator (not OEM).
Removing condenser and fully cleaning /washing.
Installing 2 condenser fans(1 from pressure sensor, 2 is always when compressor is ON)
Cleaning evaporator and replacing expansion valve(OEM)
Replacing brand new OEM compressor.
Now it's very cold even though I have rear AC and a cool box, sometimes I even think it's even better than in my LX
(of course it's still R12 )

 

[KYLXFJ]

A 454 small block ? Like, a World block and a 4” stroke crank ? Do tell. I’m curious. Know it’s possible($$$) but not common. Very niche . . .and in your 80 ?

sorry, when I said build I meant "build of vehicle", I didnt build the motor. it was a crate motor from blueprint engines from their own casting, but deck height was same as regular SBC if i recall. I sold a caged 71 corvete with a solid roller 496 and moved onto a 78 corvette pace car I wanted to build up streetable and look stock, so the 454 sbc was part of that, as it would fit under the stock bonnet. I ruined a perfectly good cruising car with that spiraling project LOL. sorry to hijack thread!

 

[desertwampa]

Thanks for all the tips. I do have ceramic tint, its one of the first things I did. It doesn't really help, BUT in all fairness I need to still get the windshield and sunroof done, and that might make a huge difference. On my list of things to do.

Next plan of action is to get the evap and valve looked at and maybe replaced. Water pump and thermostsat age, I have no idea. Maybe them too, if the other doesn't work.

 

[rdcnj]

If you spend a fair amount of time at low speeds or idle and are using the fan clutch fan (not electric), an AUX fan will really solve this problem without any issue.

When you start getting into the triple digit temps and/or crawling on trails, there is just barely enough airflow to make them operate well. That little extra push (higher idle on fan clutch fan for example) is all it needs to go from luke warm to ice cold.

This typically means the condenser needs more airflow to conduct liquid to gas exchange efficiently.

 

[desertwampa]

If you spend a fair amount of time at low speeds or idle and are using the fan clutch fan (not electric), an AUX fan will really solve this problem without any issue.

When you start getting into the triple digit temps and/or crawling on trails, there is just barely enough airflow to make them operate well. That little extra push (higher idle on fan clutch fan for example) is all it needs to go from luke warm to ice cold.

This typically means the condenser needs more airflow to conduct liquid to gas exchange efficiently.

I have an aux fan, and it doesn't seem to make much of a difference. Maybe at lower temps but here in Vegas it was bruuuutal this summer..even now too. many days of 110 or more..

I mean, maybe my 80 can just be my fall/winter rig..it'd keep the miles low..that's for sure. jk

 

[oilbrnr]

Out of curiosity, have you relocated the dryer/accumulator or bent it for approach angle? In the back of my mind I remember reading on here somewhere that there is an effective angle that really shouldn’t be exceeded. Sorry, don’t have anything more specific, but something to keep in mind as it looks like you might have an ARB front bumper looking at your avatar pic.

 

[77mustard40]

I’m curious about the fan clutch. I modded a new blue hub and used 20K CST and almost never have seen 200F in any conditions. My truck will lock in around 186 when moving then rise as much as 10 degrees in a stopped or stop and go situation with ambient temps above 100. AC seems slightly less efficient but I never have it all the way to full cold or the fan above 3.

 

[rdcnj]

I have an aux fan, and it doesn't seem to make much of a difference. Maybe at lower temps but here in Vegas it was bruuuutal this summer..even now too. many days of 110 or more..

I mean, maybe my 80 can just be my fall/winter rig..it'd keep the miles low..that's for sure. jk

I think we have to remember the rules of A/C systems overall right now.

An A/C system is essentially designed to cool the existing air, about 35 degrees. Most of the systems we see with more than 35 degrees, are mostly new and recently had parts replaced and airflow and gas flow is clear.

At 110 degrees, the most efficient system in anyone's vehicle, is pushing out 75 to 80 degree air.

The best way to really gauge the basic health of the A/C system is to measure the temperature of the vent and compare it to the cabin temperature.

In the file below, you can see on a really humid day with not a really alarming temperature, the vehicle at idle was maintaining ~28 degrees of difference between cabin and A/C air.