AC temperature at vents

[Bill Copple]

Last time I serviced my 2010 SLT, ambient temp was 87 after running on max recirculating setting for 5 minutes at 1200 RPM I got 17.2 at the vent outlet. On recirc you bypass or sort of control the ambient intake air. On the same day about 2 minutes later in regular mode without recirculate engaged I had 28.4 at the outlet. That is a 58.6 degree temperature drop. Those numbers would be considered outstanding. (I had just replaced the expansion valve and was reservicing) I would’ve been happy with 25 - 30 degree drop. On recirculate or max mode that would get very chilly after a few air exchanges.

 

[Msko]

You probably already know this but I’ll throw it out there anyway. Put the fan on recirculate- if you are always trying to cool 90 degree humid air You will only get temp down so far. By recirculating you are cooling air thats already cooled once which will drop feels-like temp more....

 

[Retread Tom]

I have a 19 Laramie Longhorn, when the outside temp is in the 90's, the best that I can get is 43-45 degrees at the vents. They did the vent "upgrade" at my last service because my truck is an early 19. No difference. Basically my service manager said with the higher operating temps for the oils and water, it's harder to bring the air cond temps down. Said that 43-45 was pretty good. The Ram that I traded in would get into the high 30's.

 

[wfscooter]

The problem is that hot coolant from the water pump is constantly being circulated through climate control system, even when max AC is on. Bad design. Computer is supposed to control the amount of heated air being blended into the output, but it does not work properly. FCA refuses to acknowledge or fix. Problem is common across the RAM and JEEP models. Quick, cheap and easy fix is to restrict the flow of hot coolant into the climate control system. Place a fluid line clamp on the coolant line at the water pump and clamp off about 90% of the flow. I did it 6 weeks ago on my 2019 1500 and it works wonderfully. I now have 40 degree output air which is great here in south Florida.

Putting a clamp on the heater line sounds like a simple fix. From what I’ve read after seeing this, seems to be a common issue and common fix. Anyone know of a good clamp to try?

 

[turkeybird56]

Harbor freight sells 4 clamps, different sizes, fluid line clamps for $12.00....................

 

[jimboschnitz]

Gents: Firetruck41 was correct, the outlet temp for your a/c will vary depending on the ambient temp and the humidity. The higer the humidity the less variance between ambient and oulet temp. If your system achieves 20 to 25 degrees difference at 50% humidity the system is probably functioning OK. One thing to consider when you first start the vehicle don't recirculate air in the cab because it is probably superheated. Bring fresh air into the cab for a few minutes until the cabin temp cools down, then recirculate to achieve colder outlet temps.

 

[Narg]

My 2020 Longhorn is plenty cold enough. Not the coldest I've ever had, but plenty cold. If anything, it is a bit slow to cool down.

Search around this forum for this issue, it's been talked about a lot. The best trick I've seen for fixing this is to put a valve on the coolant line going into the cab for the heater. Someone posted pics on the install and all. Then set the valve about 1/2 closed to slow the hot stuff going into the cabin. They said this made a major difference. Fixed with about $7 worth of parts and a few minutes of time. I bought this stuff thinking when Summer got here I'd want to do this trick, but my A/C has been plenty good enough so I haven't bothered.

 

[Narg]

I have a 19 Laramie Longhorn, when the outside temp is in the 90's, the best that I can get is 43-45 degrees at the vents.

43 to 45??? Wow that's good for any car.

 

[Narg]

https://www.ramforum.com/threads/diy-heater-core-bypass.187/#post-1518

 

[Marshall]

20 degree is a stupid number, , Mine works good, I don't like it real cold, last couple days in western Canada we are about 34 -35c / 100F a bit warm I do have a good meter that has temp on it , but never checked it.

 

[MRFREEZE57]

It's a TXV/AXV that built into a block that's bolted to the inlet connections of the evap coil.
The oil in the system is compatible with 134a, getting the charge correct shouldn't be too bad if you have refrigeration knowledge (notice I didn't say air conditioning). :-D

it must have just a restrictor at the evap, a txv looks somewhat like a mushroom and most mfg's go the cheaper route. still I would use 134A if needed a recharge before buying the expensive stuff and give it a try. I'm sure the compressor has poe oil which what is needed for 134A. it was 95 where I live the other day which is rare for this area so my AC almost never gets used, though I am a drive with windows open guy for being a motorcyclist all my life like the feel of the open air.

 

[crash68]

it must have just a restrictor at the evap, a txv looks somewhat like a mushroom and most mfg's go the cheaper route. still I would use 134A if needed a recharge before buying the expensive stuff and give it a try. I'm sure the compressor has poe oil which what is needed for 134A.

It's definitely not a restrictor, it has the head of either a TXV or AXV. I've been around the block a several of times with TXVs that dwarf what's in these trucks. The oil won't be the problem, getting the charge correct as the truck runs the cooling fan based in part from the AC head pressure.

 

[GeoffreyXE]

I did the pinch heater hose trick on my 19 all new ram 1500 and my driver side went from mid 50s average temp at the vent to low 40s on average. The coldest all summer before the pinched hose was 48 out the driver vent after cruising at 55 for about an hour while it was night time. After the pinched heater hose I saw 38 degrees while cruising in full sun! It's a blend door issue for sure. I work outside and boy did my truck stink like sweat because I never got cold. I always sit on a towel too but that helped little. After the pinched hose trick I am dry as a bone while between jobs and my truck is smelling better. So pissed I drove my truck with crappie ac for a year. Oh well

 

[Anonymous007]

I did the pinch heater hose trick on my 19 all new ram 1500 and my driver side went from mid 50s average temp at the vent to low 40s on average. The coldest all summer before the pinched hose was 48 out the driver vent after cruising at 55 for about an hour while it was night time. After the pinched heater hose I saw 38 degrees while cruising in full sun! It's a blend door issue for sure. I work outside and boy did my truck stink like sweat because I never got cold. I always sit on a towel too but that helped little. After the pinched hose trick I am dry as a bone while between jobs and my truck is smelling better. So pissed I drove my truck with crappie ac for a year. Oh wellView attachment 217102 View attachment 217102

Im about ready to do this with my 19 as well. I read in here that if you use the pinch method you lose coolant? Is that true? Also can you share a picture of the hose that you pinched?


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[crash68]

I did the pinch heater hose trick on my 19 all new ram 1500 and my driver side went from mid 50s average temp at the vent to low 40s on average. The coldest all summer before the pinched hose was 48 out the driver vent after cruising at 55 for about an hour while it was night time. After the pinched heater hose I saw 38 degrees while cruising in full sun! It's a blend door issue for sure.

Either the blend door or on the 8spd trucks the three way valve that is supposed to direct coolant to the TMU when not needed for cab heat.

 

[scott lass 18]

wow 50 not mine and done all the ac a mechanic can do ! one thing I first did is put a cover on top of dash to help all the heat coming in ! then a tented film that just for ur front window ! really help when waiting in the sun years back ! so found out one thing the a.c. fan when idle just doesn't help cool when in traffic ! I here a v-6 fan fits in my 2010 so doing this soon more air at idle and maybe cooler when upper 90 s out ! we will find out I know engine is running hotter now 196 no 183 have a 180 t state in it now helps alot ! but u still can fry a egg in a pan on top on the engine when hungry !

 

[MRFREEZE57]

It's definitely not a restrictor, it has the head of either a TXV or AXV. I've been around the block a several of times with TXVs that dwarf what's in these trucks. The oil won't be the problem, getting the charge correct as the truck runs the cooling fan based in part from the AC head pressure.

where do you see the valve? it must be behind the firewall in the casing where the evap is, have not looked there yet. if it is a txv it will have a cap tube coming from the mushroom looking end and a sensing bulb on the end of the tube strapped to the suction line.

 

[crash68]

where do you see the valve? it must be behind the firewall in the casing where the evap is, have not looked there yet. if it is a txv it will have a cap tube coming from the mushroom looking end and a sensing bulb on the end of the tube strapped to the suction line.

You can stop trying to explain to me what an expansion valve looks like, I've probably installed, replaced and adjusted more than most. I'd be impressed if you could tell me what 30 ton capacity rooftops used a single 15 ton Alco expansion valve, and why it works.
As I described where the expansion valve is located back in post #39, it is bolted to the connections of the evaporator. It's part number is: 68417140AA
Looks like this:
the head points twords the passenger side

 

[MRFREEZE57]

You can stop trying to explain to me what an expansion valve looks like, I've probably installed, replaced and adjusted more than most. I'd be impressed if you could tell me what 30 ton capacity rooftops used a single 15 ton Alco expansion valve, and why it works.
As I described where the expansion valve is located back in post #39, it is bolted to the connections of the evaporator. It's part number is: 68417140AA
Looks like this:View attachment 217232
the head points twords the passenger side

not trying to get into a ******* contest, am curios where it is at as can not see it from under the hood and wondering if it is behind the fire wall.
my 38 years was majority supermarket systems and believe me I have replaced, adjusted and cleaned many txv's mainly due to these new blanking refrigerants. also did some rooftop AC and heat pump work.
as far as your 30 ton question, not off the top of my head, can you tell me where the pressure differential valve is for the 2 pipe hot gas defrost on a Hussmann split suction parallel rack and what PD it is set for?

 

[Ricks Ram]

I'm wondering which trucks are affected by this more than others? I have a 14 Express that originally came with the standard single zone manual temp control system. I have since pulled the dash and replaced the HVAC box and installed and programmed the dual zone ATC system so I've had both manual single and auto dual zone systems in my truck and both of them will literally freeze me out if I turn it all the way down. It gets well into the 100s here in the summer but not a lot of humidity so I guess that could be a factor as well. I'm going to put a gauge on mine when I get a chance just to check.

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