How cold should the A/C be -- '08 Civic

My daughter is the regular user; I see the car once a week and seldom drive it. I noticed a few weeks ago that the A/C was not makng really cold air as all my other A/C-ed cars did (incl a 2000 Camry). I took it in to my trusted mechanic, who found it low on refrigerant and recharged it with 0.25 lb of R-134 (incl dye). He commented that the system uses only a small amount of refrigerant (I think he said 1 lb).

After the recharge the air did seem a little cooler, but not impressively so. This week I asked my daughter how it was. She said, “Sort of OK, but maybe this car just doesn’t make real cold air like the other cars did.”

Should this car be making real cold air? If yes, I’ll run it back to the mechanic when it’s here next week.

Well, my '07 TL, which is also a Honda product and uses the same refrigerant as your daughter’s car, puts out damned cold air if I ask it to. There’s no reason to assume that the Civic is a hot-air AC car.

If you post the temperature of the air coming out of the vents and the temperature and humidity of the outside air, you’ll probably get responses that are more useful.

lion9car – Sorry I can’t be more precise. If I had the car available, and if I had a thermometer that covered the A/C range, I’d give the numbers. Heck, if I had the car I’d be willing to buy the thermometer.

The temp coming out of the vents with the AC on should read between 40-50 degrees.


They make special thermometers just for the purpose…Any parts store should have them. $6-$8…A decent A/C system should blow about 40 degree air on high cool…45 degrees is acceptable. Warmer than that, something is wrong…

Let the system run for a while. If it’s a very hot day, you won’t get to the lowest temperatures for a while. Drive around for 10 to 15 minutes.

Thanks for the advice and info. The car will be here Monday evening and Tuesday. I think I’ll try to get a thermometer by then to check it out. But I’m certain enough that the temp is not low enough, so I’ll make an appointment at the shop, too.

You can buy a very good digital meat thermometer in the kitchen utility department at your local WalMart, cheap. That’s what I use. Totally unnecessary, but reads in tenths of degrees. I repaired and converted an '85 Fox body to R134a yesterday. 46.2°F on a 95° F day.

newer cars after 93 use r134a and they cool ok and they blow colder air the faster the car is going like on a highway they work ok in city driving or stop and go. is the the fan thats mounted to the ac condencer working that will make a differnce as how cold the car is.

I thought the rule of thumb was 30 degrees colder than the outside temperature? MG-- 46 degrees on a 95 degree day? Nice!

The rule of thumb is generally considered to be 40-50 degrees but that’s a pretty shaky rule and may not work well in very hot climates.
What I look for is vent air in the very low 40s on a 100 degree day.

The problem might not be with the AC. The problem could be due to the heater control valve and blend door adjustment. Unless Honda has changed its design on or before 2008, the heater control valve used a push to close cable instead of a pull to close. This (very bad design) means that the heater control valve does not always completely close.

To test this, open the hood and follow the heater hoses to the firewall. You will see that one of them has a ball valve in it. The arm for the ball valve should be in line with the hose to close the valve. I know that is contrary to convention, but like I said, its a bad design to begin with.

With the dash control all the way to cold, see if you can finish closing the valve by hand. You can see that the cable is trying to push it closed, but that is like trying to push a rope uphill. If it closes some more, then test the AC and I think you will see 40°F air coming out the vents. It will be cold.

Adjusting the cable is a very labor intensive job. My recommendation is just to manually close this valve at the beginning of each cooling season and not touch it till winter. Honda, are you listening?

Keith – Thank you! I’ll check that first thing.

If the problem is, in fact, from the valve’s not closing, would we get heat when the controls are set to “off”? (I don’t know if that’s happening or not; just curious, and maybe looking for a quick way to diagnose. Car will be idle this weekend, but won’t be here until Monday evening.)

“Labor intensive” – I won’t even think about doing it myself. Last I looked, Haynes had not published a manual for this one. And weather is hot as blazes here.

There will be hot water circulating through the heater core. The fan blows air across the evaporator core first, then thru the heater core because the blend door does not completely close either.

The AC might be working fine, it could be heat is still coming into the system. Cycle through all the settimgs, see if you hear any unusual noises. Does the fan vary in speed with the different settings?

Thanks again, all. I’ll have the car Monday evening to try all these ideas, and Tues morning I have an appointment at the shop. I’ll post back the results.