Air Conditioning Not Cold

[ShadowsPapa]

You’ll want to use a real thermometer, put it in the vent, let it run for at least 10 minutes. There’s no chance in hell that the air coming out your vent is 4.7F. Celsius would make sense, but no car AC on earth puts out below freezing air. 4.7 degree air directed at your face would injure people.

Well said. When I was doing automotive AC in the 70s and 80s, I had a thermometer sort of like a small meat thermometer. ( I still have it and my old AC tools). It had a dial, and a long stem likely made of aluminum because aluminum is a good conductor. You stuck the stem in the duct and waited a couple of minutes. If it hit about 37-40 you were good.
That's measuring the AIR temperature and you know to get 40 degree air the evaporator coils have to be colder than that because there is no way to get perfect heat transfer and you are moving the air past the coils so it's not going to lose as much heat as it could if it were sitting around the coils not moving.

Those non-touch or laser thermometers, at least mine, says not good for measuring the air temp. It measures the temperature of solid objects, not air. And there's no way you are going to get to even 10 degrees on these because moisture in the air would freeze instantly on the evaporator.
Go look at the YT videos where people throw water into the air, and the response to an AZ video showing an egg cooking - someone in IL said "Oh, look at this" and broke an egg and let it fall and it froze. Anyway, on a humid day like today where the dew point is close to the temperature as it is - your evaporator is going to freeze over with the water in the air even at only 25-30 degrees. Heck, I had a carburetor freeze up on a 37-38 degree day! The throttle stuck solid at 2,000 RPM and opened the hood to see ice on it.

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[BaileyW7]

I find that highly unlikely, as the whole system won’t even hold 5 pounds of refrigerant. Maybe it was 5 ounces low, which would still be a significant fraction of the system capacity.


I’m suspicious of your measurement technique. Design temperature for automotive A/C is about 40 degrees F. At 4.7 degrees, you’ll soon ice up the evaporator, regardless of humidity content.

Kevin

I may be off on the unit of measure but yea it was low and the LAT of the system was in the 40’s and should be in the 30’s

 

[punk'n]

Well, it looks like I need to ask my wife if we have a meat thermometer.

I thought the infrared hitting the plastic of the duct/vent would register correctly since its not really picking up air temp. But, thanks for the HVAC lessons.

Although, I'll still stick with saying it was blowing COLD.

 

[ShadowsPapa]

"There's just something about the cold air blowing out of those ducts that I like............"

 

[Kevin_D]

Although, I'll still stick with saying it was blowing COLD.

I will certainly agree with THAT!

Kevin

 

[Shaqeroni]

A couple of days ago (it was about 80 degrees out) I took the temp of mine while on low temp setting with the fan on high. I used an infrared thermometer. Of course, they say these can be off by +/- 3 degrees or so but it was blowing COLD.

4.7 degrees cold.

Ummmm...probably not.

 

[ShadowsPapa]

Ummmm...probably not.

If he was Canadian, I'd believe it. That's roughly 40 degrees F - but the image is fuzzy, is that a C or an F on the screen?
Otherwise, I've got some buckets if ice cream I'm bringing over and loading in his JT for safe keeping.

 

[MrZappo]

It's not even a question. 4.7 is impossible. It's either set to Celsius or it's broke.

Commercial freezers don't even have an 80 degree temp delta.

It's in the 40's. Which is design spec for typical automotive applications.

And as he said, it's cold. So none of this matters.

 

[exfil offroad]

Started having this issue the other day. So it's about 90 degrees here right now and you can imagine what the temperature inside the cab is like after a full day in the sun. Go to turn on the AC in Auto mode and it blows but only air not cold air. I decided to give it a few minutes but 10 mins later I decide it's not going to blow cold. Putting it into A/C mode and off of Auto doesn't change anything. This is at 11K miles so far. Has anyone else experienced this issue?

is this now always like that, no cold air, or only after start stop engages.

 

[ShadowsPapa]

It's not even a question. 4.7 is impossible. It's either set to Celsius or it's broke.

Commercial freezers don't even have an 80 degree temp delta.

It's in the 40's. Which is design spec for typical automotive applications.

And as he said, it's cold. So none of this matters.

No fun, eh?

We measured air coming through the evaporators of automotive AC we worked on and saw 37 without any problem. We had probes we put into the ducts and got the temperatures that way.
In the 70s and 80s, temps in the upper 30s near the evap were not uncommon.
I've frozen some evaporators over the years hot-wiring the compressor due to thermostat or switch issues.
Average discharge air temperature of 45 (AMC spec) means that evaporator is colder than that due to the heat loss through the ducts.
Anyway, if it's C, he's right on the money pointing that thing down into the ducts.

Anyway, there's TSBs out on the AC on these - the troubled one may need to be seen by a dealer. When they flashed mine it totally changed its behavior. It always worked, but it really works now. Sometimes it almost over-compensates for the sun coming in.

 

[Shaqeroni]

Started having this issue the other day. So it's about 90 degrees here right now and you can imagine what the temperature inside the cab is like after a full day in the sun. Go to turn on the AC in Auto mode and it blows but only air not cold air. I decided to give it a few minutes but 10 mins later I decide it's not going to blow cold. Putting it into A/C mode and off of Auto doesn't change anything. This is at 11K miles so far. Has anyone else experienced this issue?

I didn't see your thread before I just posted the same question.

https://www.jeepgladiatorforum.com/forum/threads/air-conditioning-system-leaking.59513/

I also have about 12k miles with no AC. I have had 2 service appointments so far. One to put dye in my refrigerant and the second one yesterday where they said my hoses were leaking and they would order me new ones. Have you brought yours in yet?

 

[ShadowsPapa]

I didn't see your thread before I just posted the same question.

https://www.jeepgladiatorforum.com/forum/threads/air-conditioning-system-leaking.59513/

I also have about 12k miles with no AC. I have had 2 service appointments so far. One to put dye in my refrigerant and the second one yesterday where they said my hoses were leaking and they would order me new ones. Have you brought yours in yet?

Seriously - the dye showed leaking hoses? Interesting. Frustrating for sure on your side of it all, but from here, interesting, and weird. I expect that from a 30 year old vehicle, but geesh.........

 

[Shaqeroni]

Seriously - the dye showed leaking hoses? Interesting. Frustrating for sure on your side of it all, but from here, interesting, and weird. I expect that from a 30 year old vehicle, but geesh.........

I agree...a nearly brand new vehicle. The red flag for me, however, was the short length of time it took them to diagnose the problem. They had it in the bay for less than 15 minutes. It must have been completely obvious or it is a best guess and that's what we're going with. I will ask more questions when I go back in the 3rd time for the "repair."

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