Air conditioning Hack

[KcRay]

I am not looking at my truck right now, but wouldn’t it make more sense to install a “u” into the heater core line so that you aren’t changing the flow from the water pump? That way the water will pump towards the core and return just as it would before. (Maybe it is a simple Tee off the main lines so this wouldn’t matter). They do sell adjustable bypass valves like this, although I don’t know that I’d want the added complexity. There are plenty of U hose kits on ebay etc.

What is the diameter of the heater core line? Asking for a friend.

If anyone does this, don’t forget to cap off the heater core as well.

I’m not surprised at the results, in most vehicles the heater core is practically right next to the AC evaporator. I do wonder if there is any increased risk of evaporator freeze up or similar.

I’ve still got my fingers crossed that my dealer will perform the AC TSB next time I go in for an oil change. I will say that after my last trip to the dealer I could swear that I heard the cooling fans on high much more than I used to - not sure what update might have influenced that or if it is just my imagination.

5/8 heater hose

 

[KcRay]

Does that valve allow you to partially open it so that you could reduce but not completely cut off the flow? Could that allow the a/c system to adjust cabin temperature?

Yes you can open valve a bit to let in some hot water

 

[19RamLimited]

Real shame people are going to this length for cold air. Amazing you did this and much appreciated. I dont know what ram is going to do here in the next few summer months. I know there re going to be a lot of dealers with unhappy customers complaining their AC is not cooling well enough. I was one of them last year. Bought mine in July and just was so excited. I was like a kid at Christmas . I had the update done to one and it made no difference. I got rid of the truck. I cant have insufficient AC. Thats my breaking point. Despite the other issues I had I cant accept that my 2019 truck AC is worse than the 2013 Ram. I have neither now. Maybe in a couple years Ill come back around but I won't until I verify a few things are taken care of.

Congrats on taking the initiative to do this. Thanks for sharing it. Great work and really great to see what people can do when driven to.

 

[KcRay]

Real shame people are going to this length for cold air. Amazing you did this and much appreciated. I dont know what ram is going to do here in the next few summer months. I know there re going to be a lot of dealers with unhappy customers complaining their AC is not cooling well enough. I was one of them last year. Bought mine in July and just was so excited. I was like a kid at Christmas . I had the update done to one and it made no difference. I got rid of the truck. I cant have insufficient AC. Thats my breaking point. Despite the other issues I had I cant accept that my 2019 truck AC is worse than the 2013 Ram. I have neither now. Maybe in a couple years Ill come back around but I won't until I verify a few things are taken care of.

Congrats on taking the initiative to do this. Thanks for sharing it. Great work and really great to see what people can do when driven to.

It really is a shame that something this simple yet drastic, can prove without any doubt that we know there is a real problem here. I think we all believed that Ram knows of this problem, they just don't know what to do about.

 

[Thewrangler73]

Does anyone know the TSB info for the A/C update? I can't find the bulletin anywhere.

 

[Jhill]

Does anyone know the TSB info for the A/C update? I can't find the bulletin anywhere.

TSB 24-001-19 from early pages of this thread that applies to trucks built prior to 09-20-18. I also attached a general AC checkout procedure for all 19 Ram trucks. If you want cold AC, put a valve on heater core supply line. The cold air is being warmed from hot heater core and blend door not closing heat off. KcRay got vent temps in high 30's after shutting down heater core. May be wise to reduce coolant flow but not stop it totally as it may be that some heat is needed to keep evaporator from freezing during humid weather.

 

[Hackmunch]

how could ram fck this up lol

 

[GoMango16]

I would be careful not to block all the hot flow off the core as this will cause the condenser to freeze over and cause other issues especially in humid climates. Good idea but don't close all the flow off.....JB.

 

[chemist2000]

I would be careful not to block all the hot flow off the core as this will cause the condenser to freeze over and cause other issues especially in humid climates. Good idea but don't close all the flow off.....JB.

What would be the potential other issues?

 

[GoMango16]

The core icing up as a % of warm air from the heater core keeps the a/c core from freezing over. Sort of like the old fridge's building up ice inside.

 

[TruckDriver]

The core icing up as a % of warm air from the heater core keeps the a/c core from freezing over. Sort of like the old fridge's building up ice inside.

To that end, it's likely the blend door doesn't close all the way (or has bypass holes in it even at full close) to allow for thawing the a/c core. There's probably a significant margin of safety designed in to prevent freeze over that is seen in this hack; but FCA has to do that to ensure consistent enough performance of the system as a whole in all climates (dry or humid, etc)

*EDIT* If someone can get their hands on the HVAC ducting schematics, you'll likely be able to see if the blending system has a bleed/passthrough built in which is something OP is artificially controlling via the valve

 

[Jhill]

The core icing up as a % of warm air from the heater core keeps the a/c core from freezing over. Sort of like the old fridge's building up ice inside.

Anyone that adds valve should think about possibly freezing up evaporator as mentioned. Reduce coolant flow but don't 100% stop flow. Part of design is that some heat supply is needed to keep everything working.

 

[GoMango16]

Right, if you shut all the warm water off you stand a chance of freezing the core and it will cause other issues. You need little flow through there token the ice off of it....JB.

 

[Gladiator77]

Today I was able to get 36-38 degrees blowing out of both the drivers side and the passenger side ac vents. Previously I was getting 44 out of the passenger side and 50-52 out of the driver side. I installed a water shut off valve in the heater hose going from water pump to the heater core. It's the outbound side of the pump says "out"right on the hose. This stops any hot water from getting into the air conditioning system at all. You will have no heat for the heater you will have no way to control the air conditioning temperature it will be as cold as it can be. This was only a test for me if you decide to do this it will be at your own risk. In essence this proves there's definitely a blend door issue inside the dash letting hot water into the HVAC system when we are telling it not toView attachment 25616View attachment 25617View attachment 25618View attachment 25619View attachment 25616View attachment 25616View attachment 25617View attachment 25618View attachment 25619View attachment 25616View attachment 25619

Do you remember what your outside temp was when you did this shut off valve change ? I'm curious when you got 38 out of your vents what was the weather?

 

[KcRay]

Do you remember what your outside temp was when you did this shut off valve change ? I'm curious when you got 38 out of your vents what was the weather?

Low 80s

 

[Gladiator77]

Low 80s

I have the vice grips on as hard as I can squeeze them and with the outside temp at 84 the vents still around 42 with 15 minutes of driving. It seems to works hard to get to 42... Do you think its not going to get in the 30s? Either way its by far better then it was!

 

[KcRay]

I have the vice grips on as hard as I can squeeze them and with the outside temp at 84 the vents still around 42 with 15 minutes of driving. It seems to works hard to get to 42... Do you think its not going to get in the 30s? Either way its by far better then it was!

Are you sure you are on the inlet hose to the heater core. Please be careful to not harm your hose. Unclamp those vise grips

 

[Gladiator77]

Are you sure you are on the inlet hose to the heater core. Please be careful to not harm your hose. Unclamp those vise grips

The hose coming from the water pump that says out and going into the firewall? And it has that braiding stuff over it it should be fine..?

 

[KcRay]

I just talked to the master "reefer repair" guy where I work. The kind of reefer units the go in tractor trailers and can keep them at -20*
He said he saw no problems at all with closing off the heater core to get as cold as air as I could, could not see any risk of "freeze up". Also said "why not all the big rig trucks do too".
Granted he is not an auto AC technician, so it's another man's opinion. We stood around my Ram this morning with the hood open looking at what I had done, talking about the situation. Said he would "do it too".

 

[chemist2000]

I just talked to the master "reefer repair" guy where I work. The kind of reefer units the go in tractor trailers and can keep them at -20*
He said he saw no problems at all with closing off the heater core to get as cold as air as I could, could not see any risk of "freeze up". Also said "why not all the big rig trucks do too".
Granted he is not an auto AC technician, so it's another man's opinion. We stood around my Ram this morning with the hood open looking at what I had done, talking about the situation. Said he would "do it too".

Great news! I spoke to a few mechanics and they see no issues with anything freezing up either as well as no issues with "stagnant" coolant. Seems like a no brainer now!