Poor A/C performance when car is hot inside

[Zee09]

My 2025 Accord Hybrid had a weak AC unit compared to all my other cars.. Woefully underpowered ...
Never what I call cold.....
No, I never used Eco mode either.

 

[brages]

My parents 2018 Subaru A/C seems to get colder with more rpms. I wonder if you're low on refrigerant?

The compressor is electric so its speed is independent of engine rpm

 

[brages]

When was the last time you changed the desiccant element? Only reason I ask is because not replacing it every few years (especially in Asian vehicles) will contribute to leaks in the system due to moisture accumulation.

how does the moisture get in?

what is the dessicant change interval?

 

[Fordiesel69]

Maybe this is like the guy with a leaky roof but it only leaks when it rains...

Anyway, car is a 2019 Honda Accord Hybrid. A/C had been working fine. Recently noticed the A/C struggling - but only in particular situations.

If the car has been sitting in the sun on a 90 degree or more day, and you start driving, the A/C is very weak. It's a little bit cool on the passenger's side but not at all on the driver's side. If you get out on the highway and start driving, eventually you get a little bit of coolness from the driver's side and after 15 minutes or so, it starts feeling pretty good.

In my typical use, I drive to work in the morning and A/C is fine. Park in a covered garage and drive home and again it feels fine. Even stopped in traffic, it's good enough to keep up in 90+ weather.

I haven't done any diagnostics and probably won't for a while, besides looking to see that the condenser/radiator fan - there is only one - seems to be running. There is an extended warranty (10 year, unlimited miles - yay!) on the condenser due to leakage from corrosion, and I'm going to take it to Honda and hope that's the problem. My appointment isn't for a couple more weeks.

The cool air on the passenger side and warm on the driver's side is something my Odyssey did when it was low on refrigerant. I guess there's enough liquid coolant hitting the evaporator to chill down the right side, but it's all vapor by the time it gets across to the left side. But the odd thing to me is that the A/C works pretty well most of the time.

This is a r1234yf system. I ordered some adapters and dye for it, but I think I'm just going to let Honda take care of it (hopefully under warranty).

So first step in diagnositcs is to learn how to select and deselect "RECIRC" in your specific vehicle. Every car maker lables it different. Ford calls this NORM AC, and MAX AC which really sucks. MAX AC is recirc. Dodge uses a symbol to toggle this on and off.

The standard way to air condition any heat soaked car is to first open all 4 doors and get the bulk of the heat out. Start up engine and set a/c to high fan but with NO RECIRC, you want the car pulling air from the outside to positively pressurize the interior, forcing the hot heat out the bleed vents or your open windows. When you depart leave driver window cracked, and passenger rear half way down. In approx 3-5 minutes of driving, or when you can start to breathe in your car, roll the windows up, and then select "RECIRC". This will close the outdoor air damper, and pull the air from your cars interior, run it thru the evap coil and this will slowly drop the interior temperature thru heat transfer. Remeber, air conditioners do not cool, elementery speaking they remove heat by absorbing it into the refrigerant and getting rid of it thru the condensor coil. How do you do this? By using the recirc option! If you stick a temp probe in your vent, you will see a 65 to 75 degree outlet temp at first. Then as you drive and your interior begins to cool, the outlet temp will drop to 40 to 55 depending on the design of your AC system.

I have gotten into blood bath arguments with friends that dont know how to operate their AC and they use outdoor air the whole time, and complain why the AC wont perform when its hot out. Duh! You are bringing in 90 degee air with 80+% humidity, running across a tiny evap coil under your dash, and expect it to be ice cold coming out the vents. No wonder it doesnt feel cool. Using RECIRC or MAX AC eliminates this problem and allows the AC to function as intended.

 

[danstraylee]

how does the moisture get in?

what is the dessicant change interval?

When the element can no longer trap moisture. It is impossible to prevent moisture entering a AC system. That is why there is an element to trap it. Older R12 and 134 refrigerants did not have this issue as much as 1234 that has been used since around 2014.

I have my element changed bi-anually in my Passport. Last time I had it done it cost about 200 bucks.

Filter drier in my home HVAC system is changed about every 5 years during routine maintenance.

 

[zzyzzx]

Isn't Honda famous for weak and failing A/C?

 

[Hermann]

The A/C in my 2005 Accord 4-cyl was great. Only wish the rest of the Monday made car was as good.

 

[kschachn]

When the element can no longer trap moisture. It is impossible to prevent moisture entering a AC system. That is why there is an element to trap it. Older R12 and 134 refrigerants did not have this issue as much as 1234 that has been used since around 2014.

I have my element changed bi-anually in my Passport. Last time I had it done it cost about 200 bucks.

Filter drier in my home HVAC system is changed about every 5 years during routine maintenance.

How does the moisture get into a pressurized system? Generally the only time moisture gets in is when the system is open to the atmosphere during some sort of repair, or by neglecting a discharged system. Water isn't being manufactured inside on an ongoing basis.

So you evacuate the system, replace the desiccant and then recharge it as routine maintenance?

 

[slacktide_bitog]

Open the windows first, and the sunroof, if you have one. Let the hot air escape, then turn the AC on after a few seconds.

Hondas of that era do have weak AC, around the time they switched to 1234yf