DavidF

Gpzguy has it spot on and is giving the best advice on this thread. I too hold an EPA certification for automotive A/C systems. Basically, that just means I took an online test, passed it and am now allowed to purchase R-12 refrigerant (notice I did not say Freon as that is a brand name of the Dupont company and not all R-12 system had "Freon" in them). Anyway, R134a systems are far inferior to the old R-12 systems as the R134a refrigerants do a poorer job of shedding latent heat in the refrigerant (thus the need for a much larger condensor). So, to get rid of this latent heat, the refrigerant charge and air flow across the condensor are critical.

The BEST course of action (IMHO) is to recover the remaining refrigerant charge, evacuate, then recharge to exact factory specs by weight or volume (will be on green label in engine compartment). The WORST think you can do is dump in refrigerant hoping you get it right. If you dont monitor the pressures when doing so, you run the risk of either damaging the compressor or dumping the charge (pressure relief valve).

Also, even with a proper charge, you may notice reduced cooling at idle especially when the outside ambient temp exceeds about 95 degrees F...again the ability (or lack thereof) of R134a to shed latent heat.

I have one car that still uses R-12 (1980 BMW 633CSI) and the a/c performs better than all the R134a systems (except for the low air volume of the 633).

mbp727

**note: when I talk about the "air" I'm referring to the air coming out of the vents, not the general air in the entire vehicle
I also have a similar problem that only arises during summer here in Florida. When the car does get extremely hot it takes a horribly long time to get the air to cool down. Even if you let the car idle, it wont get cold even after 15 minutes, unless the car is driven (and driven with some oomph...).

I know the logical response is that the car is hotter and therefore demands more time to cool off, but the amount of time it takes to get cold air is far too long. It seems like the air con needs a long time to warm up (?).

If the car was driven earlier in the day (maybe a couple hours) and still left to get hot, it has a fairly easy time getting the air coming out of the vents to cool down however after 3-4 hours it gets a whole lot tougher to cool the air down. The air should be cold after a minute, max.

Don't be mistaken though, the air will get cold (very cold), it just takes some time. The car has been in the garage all night now so if I start it up now the air will get cold in a very timely manner