Question about Air Conditioner
 

My high pressure switch has to be replaced. If I remove the high pressure switch will the freon leak out to atmosphere, or is there a schrader valve on the high side line at the switch. See photo. Thanks.

I "believe" there is a schader valve in the fitting.

But, you can just unplug the connector and put a jumper in it, and by-pass the switch. I ran mine like that for 3 years.

It is a safety device to shut off the compressor if the pressure gets too high (which is really high).

But there is also a "solder plug" in the dryer that will blow out if the pressure gets that high anyway.

Thanks. I thought of that but unfortunately the switch that does not work is the high pressure switch not the dual pressure. The high pressure switch activates the condenser fans when the pressure goes above 220psi. The normal high range on the ac is about 213psi. Bottom line is that when I have my ac on and the car idles at a light the condenser fans do not turn on. Heat starts to build up on the condenser and the pressure starts to build up real high and the cooling inside the car starts to drop. I checked the condenser fan circuit and it does work. I can switch or ground the high pressure switch and fire up the fans. I can do the same with the high temp switch on the thermo housing. Personally I would just probably put in a switch and fire it up at idle like you suggested but my wife drives the car occasionally. I would hate to remove that switch with no schrader valve and lose all my expensive r12. See the photos.

ok ... yes this is off the subject
 

this is a lil strange but i think i have your twinhttp://www.toyota-supra.info/forums/...attach/jpg.gif

Well, I can understand when someone else drives the car, which I never allow. But I don't know if there is a schrader valve in there or not. Perhaps someone who has removed their ac system can check those fittings for you.

I know what you mean about others driving the car. I tell my wife the only important gauge to watch is the temp gauge. I figure a total failure of oil pressure would be rare.

On the switch note here is a picture of the switch. The part the screws into the high pressure line. Does not look like there would be a pin or other mechanism that would push on a schrader valve. Take a look.. See what you think.

what? Your car's are totally different:confused:

Still looking for a ac shop that reclaims or recovers r12. One guy told me I should change out the receiver / dryer if I am going to evacuate the system. He states it is very inexpensive and it acts as a filter for impurities and removes moisture from the system as well as a reservoir. My system cools very well although it is a tad low on freon and has not been opened to air since 1991. Any thoughts. I hate to fix things that are not broken.

Yes.. Delete it and gain a 10th of a second.

Best mod I ever did.

If the ac is working, and cold, and just a bit low on freon, leave it alone.

The receiver/dryer should only by replaced when the system needs to be opened, like fixing a broken hose.

"Don't Mess
With Success"

I like your thinking but remember I am going to replace the high pressure switch and the system will be open. Not for long I hope. Just long enough to unscrew the switch and put the new one in. Vacuum the system and then recharge it. What is your feeling on that? Thanks.

Vacuum it down for a full hour, and this will remove 98% of the moisure in there. Then recharge it. Are you going to refill with the "very" expensive R-12 ??

R134a blows and not in a cool kind of way.

You know your stuff mrnickleye. I went by the ac shop today and the guy told me that the machine they use to reclaim the freon removes the moisture from it and filters it. When they vacuum the system moisture is also removed. He suggested that changing the drier was not necessary. Now the bad news. The estimate for reclaiming, vacuum, installing the switches and guesstimating on a additional 5oz of freon was $260.00.... The ac guy must of seen my jaw drop and hit the ground. He suggested I run the fans on a switch. According to him in Sunny south Florida you can't have a head pressure to low or blow to much heat off of your condenser. Lucky for me they had used the last of their r12 and had none in stock. I jumped back in my car with my wallet still full of money. Very good day I would say.

Yes I am going to keep my r12. A retrofit is not in my plans.

That r12 is ice cold.

I was just saying r134a sucks. I know the r12 rocks.

They did all of this noise back in 98/99.
Everyone was supposed to convert to the 134a and somehow this never quite managed to happen.
And freon and ac's all across america have been dorked up ever sinse.

So we still have guys with piles of cold air blowing blackmarket freon.

I agree with you. 134a is not as cold in a old retrofit system. As far as black market freon. Welcome to America. If you got the bills its not illegal. Cross the border to Mexico and its in ample supply.

i put the r134a in mine, have no complaints about the cooling effect.... Usually its too cold ;(

You're cold blooded then.

R134a is at its worst when you're sitting in traffic and going no where.

That's my largest complaint. I still say delete that thing.

Removing the condensor opens up the radiator to more air flow. Anything you can do to prevent any type of over heating is a plus.

I hear ya though it's not a mod for the weak of heart cause the car does get hot. I just drive faster:).

Often enough mine blows frost at me lol o.o

but ill pick up a thermostat and check it out at idle....

Never idle'n in traffic... just isnt any out this way lol

Right on. It's all good.

Just curious if this is an across the board thing or if there is another reason why r134a is said not to work well retrofited into our cars

becuase my AC blows colder than my wifes 08 corolla

One thing i have noticed though i dont get enough air blowing out of certain vents and like when i switch to defrost it still blows out the same holes... lol

Enough gets redirected to do whats needed but i dont think it works quiet right

Nope. That's it working perfectly well.

Well in closing. The high pressure condenser fan switch and the high low dual switch do not have schrader valves. I bit the bullet and had the ac shop recover the r12 and they vacuumed it down. I did not replace the dryer. I figured if I had any major issues come up with the ac I would just convert it and replace the drier then. The switches were replaced and the system was recharged and leak dye was added. Ac blows ice cold, 42 degrees cold. Its been about 3 weeks and the system still blows cold, with no bubbles or foam in the site glass and I used a black light to look for any leaks and could not find any. Keeping my fingers crossed.

I asked the ac guy about the retrofit to r134 and he said it would work ok on the 7mgte turbo model with the auto trans. Why that specific vehicle I asked. Well he explained that with the r134 you really need a large condenser. Most r12 fitted cars had small condensers. The 7mgte just happens to have the large fan / fan clutch combo and auto tranny 7ms have the extra fan in front of the condenser. Without those extras mentioned the ac would probably not blow very cold in city driving and idling.