KcRay
Well-Known Member
Same here, seems like there's a number 8 fan speed in auto mode.
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Air conditioning performance
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RBRK
Well-Known Member
My A/ C has been pretty good since I’ve had the pcm flashes and HVAC update that may or probably didn’t do much. Anyway I decided to swing by the local harbor freight and put a clamp on the heater hose. Drove home with a digital temp gauge in the vents. I actually was blowing 39.7 out of the passenger vent in a short time. I put it on in the parking lot and drove about 10 minutes home. This was on max a/c. Auto rose the blower speed like usual and it went up 2-3 degrees. It’s 98 degrees on the dash and it’s blowing 39.7 passenger and 42 out of the drivers. Pretty impressive. I got home took the clamp off and held the RPM to 1500 and it was blowing 47.6 drivers side. I know it’s been posted before but I just was giving my results. The clamp or valve obviously helps. When it’s 90 here mine seems great. It’s just been super hot and I was curious to see my results. Last year my truck was blowing 60 drivers side and never cooled down.
If FCA was smart they would put in an electronic valve and a sub harness that hooks into the factory wiring so it would close when Max A/C is desired. It could be that the blend door isn’t sealing when closed like if there is foam on the door it could be an issue or even the door is too small causing a bleed through loss around the door. I don’t see an easy fix for this. I hope I’m wrong.
If FCA was smart they would put in an electronic valve and a sub harness that hooks into the factory wiring so it would close when Max A/C is desired. It could be that the blend door isn’t sealing when closed like if there is foam on the door it could be an issue or even the door is too small causing a bleed through loss around the door. I don’t see an easy fix for this. I hope I’m wrong.
Good to know...I'm like you...getting around 47 out the driver's vent with no modifications. I think that's probably good enough and will give more than acceptable cooling performance for me but if I ever need to, I can clamp down the hose for ultimate cooling.
Wow now that doesn't make logical sense. Anyone else elaborate on this aspect of things. I too would think that
closing the rear vents would boost CFM pressure for the air coming out of the front vents.
What was your ambient temp outdoors? Thanks.
Off the top of my head, (1) closing vents might raise velocity in remaining open vents to a level of turbulence, resulting in louder but less efficient airflow delivery, and (2) cool the cabin unevenly, leading to hotspots and perhaps never fully cooling the cabin. But I’m just spitballing.
Info was upthread but it was 73 degrees and 80% humidity. We had a heat wave over the weekend with temps near 100 and truck felt perfect inside but I did not check until today.....supposed to be near 90+ by this weekend so I'll recheck.
Gman
Ram Guru
It's like trying to cool your entire house with half the registers closed. Volume counts, not "pressure".
moosem
Ram Guru
Gman
Ram Guru
Ok......but, we're not attempting to get a whole cabin temperature...for the most part all of the tests done here have been for temps at/inside the vents. An overall cabin reading/test would also be interesting and I can see that all vents should be open for that....but not having the rears open for a specific front vent test should only help (or at least not affect) a temp reading at those front vents.
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Gman
Ram Guru
That depends on what your intended goal is. If you're only concerned about the temperature coming out of the vents, sure. If you actually care about the internal cabin temp, then you're only testing one piece of the entire puzzle. If you're looking at an equivalent volume of air, with the same circulation patterns, then the temperature is relative.
In other words, if the AC can't cool the volume of the cab, no matter how low the temp is coming from the vents, then the system is inadequate. If you're disabling parts of the system to get a front vent temp result, then I find it difficult to then conclude that the system is deficient.
I have experienced a notable difference in the cooling ability at idle with the fan vs. driving the truck. I wonder if there's something that FCA can change to improve function at idle, or if it's a limitation in the cooling area of the condenser affected by the round fan vs. the entire rectangular area cooled as the truck moves forward.
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DraKhen99
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This logic makes sense, especially if you're sitting in a heat-soaked truck. If the air is moving slower through the dash vents, it's picking up the heat energy from the hot dash parts, and thus would exit the dash vents at a higher temperature.
Has anyone taken apart a new DT dash to see what the ducts look like? Perhaps some sort of insulation could be added to the duct work to make exit temps lower?
-John
First full disclosure. I don’t own a Ram but was considering buying one. However since I live in the gulf south an a strong A/C is a must I’m not sure that will happen.
From what Inread here it seems the new Ram’s A/C capacity is not enough. Apparently the refrigerant charge is just 1.12 lbs. My 2016 Ford’s charge is 1.93 lbs of R-134a, almost a full pound more. Ironically when I checked my old Honda it’s capacity is 1.1 lbs and it’s cabin is way smaller than a crew cab truck. There is no fix for a system that is undersized for its application.
It can’t be the new refrigerant because Ford and GM both use it on their current trucks and there aren’t any complaints about them. As a matter of fact I had a 2018 F-150 loaner and it got just as cold as my R-134a truck. Also the previous gen Ram used it and it was fine.
I believe since the new Ram was developed under Fiat ownership their European background and cooler climate caused them to underestimate how hot it can get in the U.S. The new Ram may be fine for a hot 80 degree day in Italy but it’s underpowered for a hot humid day in Houston Texas. Their performance data shows that they find a 55 degree vent temperature at 95 degrees ambient to be within specifications.
From what Inread here it seems the new Ram’s A/C capacity is not enough. Apparently the refrigerant charge is just 1.12 lbs. My 2016 Ford’s charge is 1.93 lbs of R-134a, almost a full pound more. Ironically when I checked my old Honda it’s capacity is 1.1 lbs and it’s cabin is way smaller than a crew cab truck. There is no fix for a system that is undersized for its application.
It can’t be the new refrigerant because Ford and GM both use it on their current trucks and there aren’t any complaints about them. As a matter of fact I had a 2018 F-150 loaner and it got just as cold as my R-134a truck. Also the previous gen Ram used it and it was fine.
I believe since the new Ram was developed under Fiat ownership their European background and cooler climate caused them to underestimate how hot it can get in the U.S. The new Ram may be fine for a hot 80 degree day in Italy but it’s underpowered for a hot humid day in Houston Texas. Their performance data shows that they find a 55 degree vent temperature at 95 degrees ambient to be within specifications.
moosem
Ram Guru
Yeah, that’s it. It never occurred to them that it gets hot in Houston. Now it all makes sense!
BTW - it also gets very hot In Italy
There are incorrect assumptions here; the new Ram 1500 is advertised to provide more airflow volume than any previous system. It is very unlikely to be undersized. Here’s FCA’s quote:
“The new HVAC system features nearly 25 percent more air flow at lower noise levels, including larger front defroster vents for better performance. Improved vents give rear passengers 50 percent more airflow when compared to the previous generation.”
There have been quite a few posts discussing the actual problem (blend door actuation and/or programming); surf back through previous threads to learn more.
ColoradoCub
Ram Guru
It’s got nothing to do with the Freon snoopy, bypassing the heater core gives me plenty cold AC in 100 deg temps. It’s a blend door issue in the hvac box
Just got mine back and they flashed the FW with numbers I've not seen before. WO states, "Flashing from current part number 68277068AG to targeted part number 68277068AI. A/C is now blowing as intended."
It blew comfortably cold on the way home. I'll break out the thermometer to see if this affects the blend door at all.
It blew comfortably cold on the way home. I'll break out the thermometer to see if this affects the blend door at all.
Gman
Ram Guru
The amount of freon for a charge is largely determined by the overall volume of the system. This includes how much plumbing it takes to route the coolant and the size of the evaporator and condenser. You can't compare the weight of the freon between *insert vehicle here* and expect it to mean anything.
