AC Pro Professional Formula Refrigerant - Walmart.com

This is the one I bought. Walmart carries it, but you may be able to find it at AutoZone, Advance, etc. also. This is the most expensive kit they had ($38). I figured if I was taking the chance doing it myself I wanted to get the best/most expensive one.

-Dustin

 

Do you recall what the pressure read when you first connected?

Mine typically freezes up on longer road trips. I let the vent run (a/c off) for 5 - 10 minutes and kick the a/c back on and it works. I did some reading and it appears any number of reasons can cause the a/c to freeze up. Low refrigerant is a common fix as low refrigerant levels cause a drop in pressure which in turn drops the internal temperature of the condenser. When that temp drops below 32 degrees it causes the outside air to freeze the system and block air flow. A recharge will fix this symptom by increasing system pressure. Does this sound accurate?

I also read that the system of switches and relays are supposed to keep pressure from dropping below levels that would cause freezing. It also seems to happen on cars with smaller a/c systems - Smart Car, Prius, Civic, etc. all seem to have issues.

I've already ordered the part, so I guess I'll install it since it's cheap. I have some leftover refrigerant from a recharge on my truck so I'll hook it up and get the pressure reading and report back.

 

Also of note - seems to happen in southern climates where temperatures and humidity can get pretty high. Posters in this thread from Georgia, Kentucky, Alabama, North Carolina and Texas.

 

I think the high humidity definitely makes the problem worse.

I don't remember the exact pressure, but the kit I used has a gauge with an adjustment range that you move to match the outside temperature at the time you're recharging the system. Once I set it for the outside temperature my refrigerant charge pressure was just below the lower limit of the proper pressure range, so it was definitely low. It sounds to me like you're having the exact same problem. Before recharging my A/C would work, but it wasn't cooling as well and would freeze up after about 30 to 45 minutes of continuous use. I would have to do the same thing you did and turn off the A/C for 5 minutes or so and leave the fan running to defrost the coil. Then it would work again for a while.

-Dustin

 

I'm going to be taking the fit into the dealer I Think for the same issue. VT here. There are a number of threads on this having to shut off the AC to let the system catch up. Mine is now barely blowing cold so I think I'm due for a refrigerant flush/fill.

~SB

 

I wanted to update my experience with this issue.

I had the same issue as everyone on this thread as well as other threads. AC would stop running cold and blow hot air after driving for four hours two years ago.

Last year it got worse, it would blow warm air after about an hour of driving.

In May of this year, the AC would start out as normal, then gradually blew warmer air after 10 minutes. I changed out the AC fuse since it was only a $8 part and nothing changed. So I followed what Bama3Dr did and bought the walmart refill can and had my cousin (who is in HVAC) refill it for me.

It's been three months now and I can finally say the AC has been fixed. I just completed a three hour drive this weekend in 90+ degree/humid NY weather and for the first time in years, had to actually lower the AC because it was too cold.

 

Your symptom description matches perfectly what happens when the refrigerant level is slightly low. Slightly low causes the evaporator to freeze up and you get no heat exchange causing warmer air to blow into the cabin. You have a very slow leak refrigerant somewhere that took several years to get to the critical stage. You probably would never find that leak since it is so small. You took the route I would have done. There is no need to "flush and refill" which is really evacuate and refill. Adding a little bit of refrigerant while watching the gage got you to where you needed to be. If it does it again in a year or two you now know how easy it is to top off of the system.

As a side note. If you find yourself needing to top it off more that once per season, your leak has gotten larger and you probably will need to find it at that time.

For now, congratulations and welcome to the world of automotive HVAC. I spent today fixing my home AC. They are much simpler to work on than automotive AC systems but the procedures are about the same. Mine quit on Sunday when it was 95 or so out and I could not go get parts until today.

 

I have the same problem on my 2009. The A/C has been weak since new, but it seems worse now.

I'll plan on buying the Wal-Mart kit if it keeps declining this summer.

 

Most DIYers think that more is better.

The opposite is true with AC systems. As you add refrigerant to an AC system the temperature in the evaporator (the heat exchange unit) rises. So less is better to a point. You do not want to reduce the charge (pressure) below the point where the evaporator is running at 32 degrees F.

At 32 F the moisture collected from the outside air that you normally see dripping out of the bottom of your car freezes on the evaporator. This ice reduces the air flow and heat exchange of the air going through the evaporator.

What I like to do is to check the air temperature at the center AC vent with a meat thermometer (available at Walmart for $10.) With the AC on FULL and recirculate while driving down the road I like to see a minimum temperature of 40 F. Most manufacturers recommend a more conservative number of 45 or 46. 40 will give you more cooling and still not freeze up the evaporator.

If you try this, do not do this on a very warm day as the Honda AC system will not be able to reach it's minimum value and you will erroneously think that you need to remove some of the refrigerant.