AC not as cold as it used to be

Thus spake thebigguy :

What was the outside temperature? A/C is only good for dropping the temperature x degrees, not putt it down to a certain level. When it hits 100 plus around here (last Thursday) my Fit had a lot of trouble getting cool for quite a while.

Are you using recirc? That helps after a bit (but surely not at first) since you are cooling air that is already cooler. But your heat exchanger can only dump so much heat. That's why cars tended to overheat back in "the good old days".

Driving during the day, hot air. Driving home at night, cooler and less humid air.

Bigguy...

Dillon's likely spot on with his answer to your "problem."

If, however, you begin to see this occurring when it is NOT quite so hot and muggy, it may be that your refrigerant charge is down a bit. Actually, it's probably likely that your refrigerant charge on a 14 year old car that's never had the AC service is marginal.

Easy to cure provided you read and follow directions. The little recharge kits they sell at the auto supply stores work great PROVIDED THAT YOU DO NOT OVERCHARGE the system. As stated - read and follow directions, and in most cases you'll be back in Iceland quickly and cheaply (>$25).

P.S. if you happen to overcharge the system, you'll know it as the high pressure cutoff will kick in and the compressor will shut down. In which case, simply bleed off (at the same port you're adding the refrigerant) some of the charge and start over again FOLLOWING THE DIRECTIONS THIS TIME

1997 CRV 135500mi Went on a trip yesterday...four pass and quite hot and humid out. The AC in the car was cool, but not cold. Sometimes it would get colder than others. On the way home that night the AC was plenty cold. Never had this thing charged or anything...any ideas?

This is likely not your problem, however. My air conditioner in my 98 CRV just was not handling the hot weather like it once did. I complained to my mechanic. He checked the coolant charge and said it was fine. He then asked when was the last time my filter for the cooling and heating system was changed. I told him never. He pulled it out and it was almost completely blocked. This needs to be pretty clean for the Honda air to work very well. Honda air conditioners have always been marginal. Everything needs to be in very good working order for things to get cool.

Michael

OK...my mechanic said probably orifice valve (TXV). He changed it and recharged the system and everything seems to be back to normal. $125 parts and labor. Dealership wanted $500. Also at lights, while stopped I have the seemingly common problem of the AC "warming" a tad and then when moving again it gets colder. What should the temp be coming out of the vent?

Thus spake Unquestionably Confused :

Here's a great debugging tool. Get two instant read meat thermometers. Put one on the front seat in the shade but in the open air. Put the other in one of the output ducts. After about 5 minutes the output should be about 8 to 12 degrees lower than the ambient. If it's not, and if it doesn't keep this differential, you have a mechanical problem. Last night it was 92 F at 8 pm. You can not and will not get a car down to 70 F. But a good A/C (like Carol's Camrty XLE) will get you around 80. Now, it was 100 plus when she got in the car after forgetting to pop the sunroof and put up the sunshield and it hadn't cooled enough to be "surviable" by the time she got home.

NB modern A/C units can do as much as 20 degrees differential. But it depends on the outside temperature.

But not so "Unquestioable Confused" has also hit something real important. And it could be multiple problems. His and mine working against your best interests.

Thus spake thebigguy :

Yeah, I always have discomfort when my orifice is blocked.

See my other post. At least 8 F below the ambient inside the car after about 5 minutes.

This is also the same methodology used to check your A/C at home.

Which is fine when the goal is air conditioning--because humidity removal is the key. 80 degrees and dry is just fine for humans.

Not to be confused with refrigeration, which is way different. Humans want conditioned air. Meat wants refrigeration.

Someone should have mentioned that to the Toyota engineers that made the AC in my 94 Previa...not that I complained too much, after too many years driving Hondas made in the 1980s....

Great description of the reality of air conditioning, Elmo.

although some may not feel like it, car a/c is in fact a refrigeration device, not a dehumidifier - the condenser is /outside/ the passenger cabin [and in a cooler location at the front of the car] to dump heat. if the objective was simply dehumidification, it would be inside the cabin and save complexity and money.

excellent point.

indeed. filters are a good thing though - they prevent the heat exchanger getting clogged with dust, losing efficiency themselves and breeding stink.

'Tis true. It's a mix, a compromise--remove enough heat to the outside, and you'll by definition remove enough humidity to be comfortable for humans, which means you can stop removing heat sooner and therefore make the system cheaper/smaller.

Unless you're Toyota designing the 94 Previa, in which case you presume it's a vehicle being used by meatpacking houses for deliveries.