a/c help - Toyota Nation Forum : Toyota Car and Truck Forums

smokey8890 · 06-23-2003, 05:33 PM

Summers here and I can't put off replacing or fixing my ac anymore. I am completely clueless about how the ac works. but the problem I have is the ac don't worth a damn unless I have it on all the way up to feel any type of coolness. But fan seems to be working good.

arcasmachineracing · 06-23-2003, 08:07 PM

Hey Smokey,

Have you put in any R-134 type"a" - lately?

I am not sure if you have a i4 but if you do, I know where the connection valve is located at if you are too lazy to find it in you manual...

Well... LATES!

smokey8890 · 06-23-2003, 08:47 PM

R-134 type"a"? damn for the last 5 yrs or so i don't think i ever did.

is that the can things i see at the shops?

arcasmachineracing · 06-23-2003, 08:57 PM

Quote:

Originally posted by smokey8890
R-134 type"a"? damn for the last 5 yrs or so i don't think i ever did. is that the can things i see at the shops?

Yeah bro... you can pick some up at your local AutoZone, Checkers, or any other shit-shop, just don't let them try to sell you the "Extra Special" R134 cause it is just a bunch of bullshit, belive me, it dosen't work any better than the "Regular" stuff, and down here in AZ (110degF) we will do anything to get cool, also, I think you can buy it "in a kit" for like 15 (< at the most) with brass fittings, they are much sturdier (sp? even a word?? LOL) than the cheap ass plastic ones, but hell, they get the job done either way!

arcasmachineracing · 06-23-2003, 08:59 PM

btw 134 is the new "eco-friendly-equlivent" of you everyday freon... just so you know...

arcasmachineracing · 06-23-2003, 09:04 PM

oh yeah and A/C systems (for the most part aren't too hard to understand...) just pick up a book from the library on Automotive AirConditoning Systems and you can learn most everything you would ever need to know about one in about an hour or so, and a little hands on experiance with your car!

rezzle · 06-23-2003, 09:47 PM

R134a may be the 'friendlier' version of R12 but the two are incompatable. Make sure you know what you have in your car before yo go adding any. R12 requires a mineral type oil and r134a requires polyolester oil. (POE)

AC works like this ...
compresser takes a low pressure gas and makes it high pressure

high pressure gas goes through condenser turns to a liquid giving off excess heat (heat of compression and heat gained from the car's interior) to the atmosphere.

liquid goes through a controlling device (TX-valve) that drops the pressure and allows the liquid to become a saturate. -something that is right at its boilling point niether gas nor liquid but in this case is considered more liquid than gas

saturate goes through dry expansion coil (DX coil) and turns to gas. (removing heat from air to turn refrigerant from liquid to gas)

gas (and maybe a bit of left over liquid on a cool day) goes to the accumulator where excess liquid falls to bottom and pure gas is drawn off the top. (its actually a U tube in a can with a small hole drilled in the bottom for oil return)

Gas from accumulator gor to compressor.'

repeat.

smokey8890 · 06-23-2003, 10:01 PM

damn you guys really schooled me big time. thanks

rezzle · 06-23-2003, 10:16 PM

Oh if your system does have a leak you should get it fixed.

If you are leaking R-12 - dichlorodiflouromethane, you are not being nice to the environment and at about 300 dollars for a recharge it can get quite costly. (unless you live in like Mexico or China where they still use and manufacture the stuff.)

Although R-134a Tetrafluoroethane contains no chlorine (which is what harms the Ozone) it is nonetheless a very inert gas (doesn't react with many things) and it is a rather large molecule that has a large global warming potential.

To repair the leak by law the refrigerant must be reclaimed and the leak fixed. Then for the system to function all the air and water that seeped into the system while the leak was fixed must be evacuated (pulled down to a very large vacuume - less than 400 microns)

Then the correct refrigerant for the oil that is in the system must be installed. In some places vehicles once had R-12 cannot be refilled. In this case a conversion is done. The oil in the system is drained flushed and purged then the new oil goes in. In some cars a larger condenser is required. The system must be evacuated no matter what kind of refrigerent is intalled. Head pressures (pressure after the compressor) get extremely high with a contaminated system and very little refrigerant actually boils in the DX coil.

rezzle · 06-23-2003, 10:19 PM

I design HVAC (heating ventilation air conditioning) units for high rises and was the plant testing foreman for 8 years before that at the company I work for.

mmtchbeary · 06-23-2003, 11:47 PM

I understand you can't run out of freon unless there is a leak?

Nick · 06-23-2003, 11:49 PM

pretty much

oh and for the ppl that don't use their ac all that often, its good to run it for a few minutes every week, mixes up the juice and prevents it from seperating (turns into stuff that eats your system up)

rezzle · 06-23-2003, 11:59 PM

What actually happens when you don't run often is the seals tend to dry out a wee bit and can shrink. That is why cars that haven't run in a while leak.

Newer model toyota's automatically run the AC every time the vent is set to defrost and the low pressure control switch is made.
Most folks defog now and then so the seals keep nice and wet, even in the winter.

smokey8890 · 06-24-2003, 09:18 PM

ok im a idiot. how do i hook up kit to the condensor? and is there any tip you guys might have?

rezzle · 06-25-2003, 07:35 AM

Take it in and get it filled properly. Too full can be very bad. Chances are you have 134a and a system charge can be done fro less than 100 bucks. That is way cheaper than getting it fixed if something goes wrong.