So I decided to test the theory that some of the Fit AC units don't have enough refrigerant. Went to wallymart and got a hose/gauge and a can of R-134a (no oil, no sealant). The pressure tested fine on my unit (45PSI - max normal) no refrigerant needed.

I haven't been having any problems with my AC, but I just had to know. Besides, I got to buy another car gadget - the AC hose and gauge. I have two vehicles with R-134a AC so it will get used another time.

 

i noticed the same issue in every manual a/c cars tested,

i believe it's due to manual a/c design.. considering normal outside temperatures, and best fuel economy instead of high cooling performance...

i was told that the temperature in the evaporator is not so cool, because there is a risk of frost if used in combination of slow vent speeds..

 

On my 93 Saab, there's a separate anti-frost switch that shuts the compressor down if the evap gets too cold. I don't know if the Fit has one. My guess is that it does because the car was designed so the AC is on when defrost is selected. The anti-frost switch would likely deactivate the compressor in the winter since it's temperature driven. I don't have a service manual to check.

 

Most cars today have a switch that if the ambient temperature is below 40 degrees the A/C compressor will not engage.

 

Even with the IAT (intake air temp) switch. The A/C will not kick on below 40 to prevent freezing of the evaporator and causing SEVERE damage to the vehicle. I would advise against going to Wally World and buying the can-o-freeze stuff for your A/C. A/C systems work on the principle of vacuum and pressure. You have to vacuum the A/C system when it's initially filled to "boil out" the moisture inside of it. Water freezes at 32 degrees F, but a/c refrigerant has a boiling point of -29 to -34 F depending on what's used. So that being said (i'll try to keep in shortened to understand) in a radiator, pressurizing the system makes the car run hotter without damage... 1 psi of pressure raises water's boiling point 3F. I don't know the exact measurement, but vacuum is measured in Inches of either water or mercury. if 1psi raises boiling point, then vacuum lowers it. If you put a system under vacuum for about 30 minutes (what most shops do). It burns the moisture out of the system. A drop of water can ruin the A/C system... Then it is filled to the correct amount after vacuuming with refrigerant. When filled, it's still under vacuuming, so it gladly accepts the refrigerant without fighting against it. If you buy the can of stuff at a department store... 1 wrong reason: The can will only supply so much to the system because the system is already under pressure and doesn't want to accept the contents of the can. 2) the cans commonly contain an oil used for the compressor that the system already has, and too much oil will cause it to not recieve enough refrigerant and cause over oiling of the compressor and it won't work properly. That stuff may cause the car to have more problems, or only work for a little while. But that's a crash course on how the A/C system functions and is filled. They're commonly underfilled from the factory, and the dealer's have to put them through a multipoint inspection before putting them out on the lot for sale. And they work on comissions only. Me working in the construction equipment business and having to do the same thing to new machine deliveries for Caterpillar... I can't hold a grudge, it commonly happens. We all make mistakes and are human afterall. I've screwed up working on stuff, that's for sure. Can't blame Honda. Just the technicians are so rushed to get them out to sale so the company doesn't lose more money holding them in the shop when they are new. It happens. -- Sorry for the LONG post. Just wanted to clarify some stuff. Hope this helps, everyone!

 

I didn't see anything here to keep me from using wallyworld unless you know those cans contain contaminated refrigerants. I bought a can without oil or leak sealant because a new system doesn't need it. Once the low pressure side tested normal, I didn't need to fill the system. The low pressure side of the system is low enough to take refrigerant from a can. It's simple to do this on the fit - one side has a grey cap with an 'L' on it, the other side's fill fitting has an 'H'. DON'T TOUCH THE 'H'!!!! The high side is under considerably more pressure than the low side (190 PSI or higher).

One error in your explaination - the low side pressure isn't under a vacuum in an R-134a system. It should be around 20-45 PSI or so. The only AC systems I'm familiar with where the low side is under a vacuum (less than atmospheric pressure) while operating are the old Lithium Bromide systems which used water as a refrigerant. They were used in some older submarines and building AC plants. Supposed to work very well as long as the operator knew how to keep the lithium bromide from crystalizing out of solution and 'rocking up' the system. Difficult to troubleshoot a leak in those systems because the hole in the side under vacuum won't spew dye to show you where it is.

Vacuum is used in new or rebuilt systems to remove as much air/water as possible from the system before filling it with refrigerant. AC systems in cars include a receiver/drier which contain a desiccant to remove any remaining water in the system. Once the system is filled, it operates at higher than atmospheric pressure.

 

I insulated the LP ac line total cost $2 and i notice a big difference in the south florida heat.

 

Do I have to crawl under the car to do that? Where is this LP ac line? Instructions please? (Make it specific, I am a girl)

 

I used 1/2 inch pipe insulation from lowe's .99 cents for 6 feet and about ten 8 inch black zip ties.

 

I like that tip about insulating the line.

San Antonio here...

Tint all around except front windshield. When parked out in the sun I use an interior sun shade on that large front window which does make a difference.

I crack open the rear windows to help expel the hot air, turn the system to recirculate and fan on high for a few minutes. Cools it down to a reasonable
temperature fairly quick.

I have yet to drive any distance on the highway yet... but I imagine once the interior gets thoroughly chilled I would be turning it down.

I used to drive my old car around without the AC on and crack open the windows... may revert back to that with the Fit, but for now I'm on a mission to keep the interior dust free from all that pollen floating around here in San Antonio right now.

 

That's a good idea. I'm gonna try that this summer, see if it helps with the NW Indiana heat, too.