Is my air conditioning blowing cold enough?

[cpwolf]

You can argue if you want. People thought the same thing about never turning off their computer. The heat a computer constantly generates, wears it out and parts fry. It is the same principle with AC. Hoses crack, leaks occur, compressors fail, compressor clutch wears out and fails, evaporators wear out and fail. Cranking up your Car AC to full with the windows down, compared to being able to turn it down, when the interior is cooled and the windows rolled up, or being able to turn it off completely, effects the toll on the AC and longevity of the AC.
Also, the drag caused by the windows rolled down, plus the extra work caused on the engine by the AC will consume much more gas, dramatically effecting fuel efficiency.
Imagine the toll on your AC driving through a dusty area like a desert with the windows rolled down and the AC on blast. The AC also has to work much harder trying to constantly replace the hot air with cool air, plus the dust has a negative effect on the AC components.
Just Google "Why close the windows in your car when running the AC". I take care of my Jeep. This is why I've had it, looking gorgeous and running great for 28 years. But, I can't force people to accept common sense. Best to you.

It's not common sense, and best to you. You can try and force what's not correct, but it doesn't make it correct, I saw a lot of that dumbness in Covid as a great example.

You're analogies or comparisons are nonsense, just to let you know. I'm in Texas, you may not have been here for the past 28 years, I have. If my top is up in June, July, or August...and probably add May and September and October...The AC is on all the way cold, and all the way up. I might, in the evening, drop it to not full blast. So in 5 straight months....The AC is blowing full on anytime the top is up. There is no "less" wear if the top is up....here in Texas.

Thanks for the "drag of windows and fuel efficiency" comments, I needed a great laugh before I went to work out this morning. Really funny, thanks. Maybe you should museum your jeep and drive a Tesla. The nonsense arguments you're making...are nonsense.

Turning on the AC at a stoplight in 100 degree heat....in a TJ....any delta is negligible at most. "Fuel efficiency" in a TJ forum....very funny though, thank you.

 

[ColoJeep]

You can argue if you want. People thought the same thing about never turning off their computer. The heat a computer constantly generates, wears it out and parts fry. It is the same principle with AC. Hoses crack, leaks occur, compressors fail, compressor clutch wears out and fails, evaporators wear out and fail. Cranking up your Car AC to full with the windows down, compared to being able to turn it down, when the interior is cooled and the windows rolled up, or being able to turn it off completely, effects the toll on the AC and longevity of the AC.
Also, the drag caused by the windows rolled down, plus the extra work caused on the engine by the AC will consume much more gas, dramatically effecting fuel efficiency.
Imagine the toll on your AC driving through a dusty area like a desert with the windows rolled down and the AC on blast. The AC also has to work much harder trying to constantly replace the hot air with cool air, plus the dust has a negative effect on the AC components.
Just Google "Why close the windows in your car when running the AC". I take care of my Jeep. This is why I've had it, looking gorgeous and running great for 28 years. But, I can't force people to accept common sense. Best to you.

As others have stated , when a TJ's A/C is on , it's on . The only thing that regulates compressor on time is the system pressure switches. The system is different from a house A/C system , which uses a thermostat that's adjustable to a given setpoint . Your Jeep does not. Additionally , most of your TJ's A/C settings pull the " dusty hot desert " air into the evaporator , just like using the recirc.setting with the top down. You can change the Jeep's interior temp. setting , but only by blending hot air from the heater core into the air delivery. I hope this helps you understand how a TJ A/C system actually operates. Thanks.

 

[cpwolf]

As others have stated , when a TJ's A/C is on , it's on . The only thing that regulates compressor on time is the system pressure switches. The system is different from a house A/C system , which uses a thermostat that's adjustable to a given setpoint . Your Jeep does not. Additionally , most of your TJ's A/C settings pull the " dusty hot desert " air into the evaporator , just like using the recirc.setting with the top down. You can change the Jeep's interior temp. setting , but only by blending hot air from the heater core into the air delivery. I hope this helps you understand how a TJ A/C system actually operates. Thanks.

"actually operates" funny how much of this is needed in our world...on so many topics.

 

[MBDIAGMAN]

20 deg below ambient is not correct.


Straight from the FSM:

View attachment 626923
View attachment 626924

I think Chris was talking Celsius.

 

[MBDIAGMAN]

Yes unfortunately people put a lot of crappy additives in the system ,I’ve seen some really bad ones,I’ll look for a pic of the one from my ranger.

Yes, I wish that magic ac cures in a container we’re not sold. It would save tons of automotive a/c systems from being destroyed. If statistics were possible, I fully expect they would show many more a/c systems damaged or destroyed than those that experienced any sort of benefit.

The magic leak stop products that are nothing more than seal swellers are benign, but the ones that tempt to plug leaks in the system are often system killers.

 

[B1Toad]

For the most part I agree with what you guys are saying about the operation, it's a "dumb" system and pretty much on or off but what about head pressure? If you are drawing in 110F outside air as opposed to recirculating say 75F cabin air the head pressure is going to rise resulting in more effort needed to turn the compressor. Switching from outside air to recirc in these conditions (and closing the windows or putting the top on) allows for lower head pressure and easier operation for the compressor and the engine driving it, as well as lower condenser temps which in turn means lower radiator temps. Supply temps will also drop allowing for lower blower fan speeds. IMHO of course. Am I wrong?

 

[MBDIAGMAN]

Back in the seventies into the early nineties, GM went through I don’t know how many different types of a/c controls and I always thought the pressure switch system was a really good system. Very easy to understand and troubleshoot. As far as the high side goes, in motion, no problem. With an electric auxiliary fan turned on by a high side switch to bring down high side pressure, everything worked out well until someone thought there would be problems overheating if the fan wasn’t running. The fan is not controlled by, or there for the purpose of, preventing coolant overheating. Made for confusion for a lot of folks, but made for a very simple and effective a/c system IMHO.

 

[B1Toad]

Back in the seventies into the early nineties, GM went through I don’t know how many different types of a/c controls and I always thought the pressure switch system was a really good system. Very easy to understand and troubleshoot. As far as the high side goes, in motion, no problem. With an electric auxiliary fan turned on by a high side switch to bring down high side pressure, everything worked out well until someone thought there would be problems overheating if the fan wasn’t running. The fan is not controlled by, or there for the purpose of, preventing coolant overheating. Made for confusion for a lot of folks, but made for a very simple and effective a/c system IMHO.

Mercedes does that on some of their models. I had a Chevy Express 3500 that I installed two 15" Permacool (pusher) condenser fans on. They were not thermostatically or pressure switch controlled, I just connected them to come on when the AC was on with an aux kill switch for winter defrost mode. I could sit at idle for unlimited periods with ice cold air blasting on me. This is important for a work van because the cab is your office and your lunch room. With both running it sounded like angry bees outside the van.
I also added the big transmission cooler which saved my transmission from early failure as is common on those vans.

Too bad we don't have room for condenser fans on a TJ.

 

[AOSJ]

I can add recent relevant info here because I used Artic freeze on my 2001 a couple weeks ago and it worked perfectly. Happened to get the can on clearance at Advance so it hardly cost anything - anyway, I had to blow off some pressure with my AC Pro gauge to get the product into the system but stopped at 40psi and the air is very cold, about 40 degrees with my Horrible Fright IR temp gun. It had the classic low freon symptom of the compressor engaging and disengaging quickly with only slight cooling.

The Artic Freeze product only has 1/4oz of "stop leak" additive and I didn't even use the whole 12oz can - I can confirm there is no leak present now (there probably wasn't before either).

 

[MBDIAGMAN]

Mercedes does that on some of their models. I had a Chevy Express 3500 that I installed two 15" Permacool (pusher) condenser fans on. They were not thermostatically or pressure switch controlled, I just connected them to come on when the AC was on with an aux kill switch for winter defrost mode. I could sit at idle for unlimited periods with ice cold air blasting on me. This is important for a work van because the cab is your office and your lunch room. With both running it sounded like angry bees outside the van.
I also added the big transmission cooler which saved my transmission from early failure as is common on those vans.

Too bad we don't have room for condenser fans on a TJ.

View attachment 628151

Very wise mods!

What model Benz did you have? Been driving Benz cars since a GI in Germany ca. 1969.

 

[KennethS]

For the most part I agree with what you guys are saying about the operation, it's a "dumb" system and pretty much on or off but what about head pressure? If you are drawing in 110F outside air as opposed to recirculating say 75F cabin air the head pressure is going to rise resulting in more effort needed to turn the compressor. Switching from outside air to recirc in these conditions (and closing the windows or putting the top on) allows for lower head pressure and easier operation for the compressor and the engine driving it, as well as lower condenser temps which in turn means lower radiator temps. Supply temps will also drop allowing for lower blower fan speeds. IMHO of course. Am I wrong?

I was under the impression the high head pressure was caused by the hot air across the condenser. You know, that whole PV=nRT thing, with hotter air across the condenser, less heat is removed from the refrigerant passing through it.

 

[MBDIAGMAN]

I was under the impression the high head pressure was caused by the hot air across the condenser.

Correct! That’s why a high pressure sensor to turn on the aux fan works.

 

[B1Toad]

So warmer air across the evaporator (vs cooler air) has no effect on pressures?

 

[MBDIAGMAN]

No, the fan blowing air across the condenser lowers high side pressure. It is warm air, but cooler than the condenser temperature. Thermodynamics at its best.

Whoops! I just noticed that you were talking evaporator not condenser.

Evaporation is a cooling process. When the pressurized refrigerant is forced past the orifice into a lower pressure area, whatever form it takes, it evaporates from a liquid to a gas. This is an evaporation process which removes heat. The pressure does indeed change based on the heat removed at the evaporator.

 

[ChasUGC]

I disagree completely.

The AC doesn’t “work harder”, because there are no components that change operation. Someone running the system with the windows down in a 90 degree environment is no different than me running it with the windows up on a 118 degree Phoenix summer day. The compressor turns, the orifice tube meters liquid refrigerant into the evaporator, the liquid refrigerant boils, the gas changes back into liquid in the condenser, and the cycle repeats. It does not change when you “turn it down” as that is just reducing the fan speed.

I really don’t know why you’re worrying about running the AC. Mine has been heavily used for 27 years in summers that are 110 and above for 3 solid months and 100 and above for 5 months, and this afternoon on the drive home in rush hour traffic and 108 degree temperatures it was blowing 40 degree air.

Your computer analogy is not applicable to an AC system. Computers typically fail due to electrolytic capacitors, which have a known operational lifetime. Think of the refrigeration system in your refrigerator or freezer. Those run non-stop, 24/7/365 for 20-30-40 years or more. It’s the exact same system operation as an automotive AC.

I'm sorry. I don't believe you. You claim to live in Phoenix, with no problems to your Jeep AC in 27 years, operating it with the windows constantly down. I call false. I'm done. You do you. I won't even tell what happened when I ran my Jeep's AC with the windows down. But, people who don't want to act responsibly and instead recklessly, can do them. Best of luck to you. I'm done.

 

[Hacker412]

For anyone with these on their Jeep, I wanted to share this information. My AC is now at least 30% colder after removing these from the grill.

 

[B1Toad]

For anyone with these on their Jeep, I wanted to share this information. My AC is now at least 30% colder after removing these from the grill. View attachment 644215View attachment 644216

I took those off and my cooling and AC went from marginal to excellent. This is after all the reading I did where people said if those inserts affect your cooling, you have something else wrong which is why it took me so long to remove them as my entire system was fresh with factory parts including a new Mopar radiator, Mopar water pump, fan clutch and Flowkooler 190 thermostat but cooling was still struggling on really hot days and I'd have to shut the AC off at long red lights and drive up windows to keep it from hitting 225F. Even my block was clean only having under 20,000 miles on a total rebuild. I had chalked it up to poor design and was considering an upgrade like the Explorer setup.

Then I happened to remove only one insert to see about installing a hood lock and noticed later that day at the drive up window the temp didn't rise like usual with just one insert removed. I went straight home and removed all of them and never looked back. I now find myself reducing the AC temp and blower speed after a bit, it gets downright chilly in that little cabin. It also now stays cool when sitting and never boils into the overflow anymore after shut down. Temps are now normal at idle and at speed, and I like the look better with that junk removed. I've been testing it all Summer in Arizona desert temps, never once has it got hot enough to concern me, and I can leave the AC on as long as I like. I only wish I had done it sooner.

 

[BC Moto]

So I used the vacuum pump on the A/C system and It held vacuum and I ran the pump for an hour and it sat for another hour for leaks but it was solid. I then proceeded to fill the system and it seems to blow cold but this is with the temp gauge in the center vents. It seems like it could get better than this...

 

[dearchristopher]

So I used the vacuum pump on the A/C system and It held vacuum and I ran the pump for an hour and it sat for another hour for leaks but it was solid. I then proceeded to fill the system and it seems to blow cold but this is with the temp gauge in the center vents. It seems like it could get better than this...

Sounds like my issue, which ended up being an aftermarket pressure switch that wasn’t properly rated for the jeeps system.

I went to an adjustable pressure switch that I thought I’d have to tweak, but it ended up being perfect out of the box.

I diagnosed it similarly to how you did, eventually noticing that my compressed would turn off too often. If I disconnected the pressure switch and just jumped the wires together, it ran long enough to freeze me out. You can’t run it like this forever or you’ll freeze your system over, but It’s a good test to see if it’s the issue or not.

 

[BC Moto]

I am going to have to look into that, I think mine is turning on often.