HVAC - Intermittent Cooling Issue

[dcs111]

Folks,

today we embarked on 12 hour road trip and at about the 8th hour the AC began to stop conditioning the air. We were running in recirc, cooling at around 72 when it was about 102 OA... it seems that the compressor timed out as the vents kept blowing, but not cool air (which is really not cool). After about 45 minutes of driving (and my wife reading owners manual, googling, and searching for open shops) the system miraculously began cooling again and just as well as before.
I am guessing either the condenser froze or the compressor overtemped and system went it to some sort of protect mode?

I am going to have a mechanic put a line set on it and pull any codes...

Has else experienced this? And if so, please share issues and outcomes!! TIA

 

[TheGrrrrr]

I occasionally get less cool or even ambient outside temp air when I’m not moving much in >100f heat. Haven’t had an issue while at highway speeds. Recently stopped running the rear system and trying to remember to not run the cool box when nothing is in it, in those conditions and that seemed to help. I doubt my experience is going to be of use but I’ve been meaning to post up about it so, maybe I can piggyback on this thread for some advice.

 

[JS22STL]

Does the display on the climate control stay lit up like it is working or does it go black like it’s off?

 

[Sandroad]

Maybe not relevant, but could be worth checking on.

https://static.nhtsa.gov/odi/tsbs/2020/MC-10176693-9999.pdf

 

[dcs111]

Does the display on the climate control stay lit up like it is working or does it go black like it’s off?

Thx for the comment. No issues with the display, control, or fans.

 

[cboyd]

The Servo TSB sounds interesting.. had not seen that before.

I had a similar issue to what you are describing on my 2015 and it did that for a couple weeks intermittently. About 2 weeks later it was blowing warm. I love in New England but we had a stretch of 90+ in early July. I took it in and had dealer evacuate, pressure check and refill. No issues since, was running low. They dyed the system to check for leaks, we’ll see. So far it has been ice cold.

one question - did you have your cool box on? I’ve heard of issues with leaks in the cool box.

 

[Adrenaline6]

Yeah , I recently noticed the rear vents were blowing warm air while the front was cold. I checked the sight glass near the high pressure inlet to the right of the radiator on the drivers side. Saw that there were bubbles in it when ac on and not a steady stream of liquid refrigerant. Bought a refill kit from Autozone. It had a digital pressure gauge already on it. Connect to the low side. The pressure looked good at 45 lbs. It says hit trigger in 15 second increments. Did it a couple times, while running the ac full blast with doors open so compressor stays running. The bubbles went away. Now it's ice cold and gets cold quicker. Problem solved.

If the problem comes back quickly, I will check for leaks.

 

[dcs111]

The Servo TSB sounds interesting.. had not seen that before.

I had a similar issue to what you are describing on my 2015 and it did that for a couple weeks intermittently. About 2 weeks later it was blowing warm. I love in New England but we had a stretch of 90+ in early July. I took it in and had dealer evacuate, pressure check and refill. No issues since, was running low. They dyed the system to check for leaks, we’ll see. So far it has been ice cold.

one question - did you have your cool box on? I’ve heard of issues with leaks in the cool box.

Of course the cool box was on! Gotta keep those ham sammiches on chill!
Yes I think once I can have someone check the pressures I will know more.. mine is a 2013 BTW.

 

[borfoo3]

1- check if ac gas needs top ups or leaks
2- make sure airflow to the ac side of the radiator is not blocked (I believe it is lower passenger area)
3- in extreme heat (>44c or 110F), you will need to be driving for a few minutes to cool the air initially. After that, it should not have issues staying cool even when stopped.
4- if #3 is not the case, check 1 and 2 above

 

[dcs111]

1- check if ac gas needs top ups or leaks
2- make sure airflow to the ac side of the radiator is not blocked (I believe it is lower passenger area)
3- in extreme heat (>44c or 110F), you will need to be driving for a few minutes to cool the air initially. After that, it should not have issues staying cool even when stopped.
4- if #3 is not the case, check 1 and 2 above

Thank you. Will check as suggested.

 

[dcs111]

Yeah , I recently noticed the rear vents were blowing warm air while the front was cold. I checked the sight glass near the high pressure inlet to the right of the radiator on the drivers side. Saw that there were bubbles in it when ac on and not a steady stream of liquid refrigerant. Bought a refill kit from Autozone. It had a digital pressure gauge already on it. Connect to the low side. The pressure looked good at 45 lbs. It says hit trigger in 15 second increments. Did it a couple times, while running the ac full blast with doors open so compressor stays running. The bubbles went away. Now it's ice cold and gets cold quicker. Problem solved.

If the problem comes back quickly, I will check for leaks.

Awesome! TY

 

[dcs111]

I had the AC checked this week and the refrigerant was low. Greer ran a dye and found the leak… Turns out, one of the rear refrigerant lines was leaking at a fixture connection. They replaced an o ring and recharged - all fine.

it was interesting to learn the schematics of the AC system as I did not realize there was a second expansion valve and condenser (among other components) for the back half of the truck.

 

[cboyd]

I am having literally the same issue. heard some “whispering” coming from the dash. Played with setting and realized it would stop with AC off. Went a week or so more and the AC blew hot

HVAC recharge, dyed. about a month and half ago. (Post 6 above). Slowly went out again. Same symptoms and whispering, the days later blows hot.

I did not run the cool box between episodes.

It’s been at the shop this week and they called today and said “good news it’s an o-ring and not the hard lines”

I don’t have specifics as I’m picking the truck up in the morning. I was under the impression that the o-ring was up front on near the compressor, but your note indicates somewhere else.

Which O-ring was yours?

what year? I’m a 2015

 

[dcs111]

I am having literally the same issue. heard some “whispering” coming from the dash. Played with setting and realized it would stop with AC off. Went a week or so more and the AC blew hot

HVAC recharge, dyed. about a month and half ago. (Post 6 above). Slowly went out again. Same symptoms and whispering, the days later blows hot.

I did not run the cool box between episodes.

It’s been at the shop this week and they called today and said “good news it’s an o-ring and not the hard lines”

I don’t have specifics as I’m picking the truck up in the morning. I was under the impression that the o-ring was up front on near the compressor, but your note indicates somewhere else.

Which O-ring was yours?

what year? I’m a 2015

Not exactly sure where this is, but appears to be under the truck. Truck is 2013.

 

[BigLexusMN]

Hello, 200 owners. I need to start out by saying this forum is amazing.

I, too, was having problems cooling the 2nd and 3rd rows in my LX, especially from the ceiling vents.

I followed the guidance here and bought a 20oz can of AC Pro and just did the process. The gauge on the bottle started right between the white (fill) and green (ok) zone. So, I decided to proceed.

With AC on full, recirc on and coolbox cooling, my rear ceiling vents went from 70 degrees to 60 degrees and I can tell and definite difference. I used the entire 20oz bottle and one empty, the gauge read 35 PSI.

Does anyone know what the spec is for pressure on these vehicles? Wondering if my system could take another bottle?

 

[cboyd]

Mine was the

View attachment 2775325
Not exactly sure where this is, but appears to be under the truck. Truck is 2013.

O-ring on mine was at the front hardline going to the back, as they told me. If it leaks again I’ll point them at this one. Thanks for the info.

 

[Adrenaline6]

Hello, 200 owners. I need to start out by saying this forum is amazing.

I, too, was having problems cooling the 2nd and 3rd rows in my LX, especially from the ceiling vents.

I followed the guidance here and bought a 20oz can of AC Pro and just did the process. The gauge on the bottle started right between the white (fill) and green (ok) zone. So, I decided to proceed.

With AC on full, recirc on and coolbox cooling, my rear ceiling vents went from 70 degrees to 60 degrees and I can tell and definite difference. I used the entire 20oz bottle and one empty, the gauge read 35 PSI.

Does anyone know what the spec is for pressure on these vehicles? Wondering if my system could take another bottle?

Pretty sure 134 systems on the low side is 45.