A/C question
Thread Starter
Instructor
Joined: Nov 2002
Posts: 158
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From: Motown mi
A/C question
As I sit here in Michigan and watch the snow................ I will be moving to Florida for the summer, and I have some questions on my A/C in my 88.. I swapped to R-134 last summer, and was not impressed. It was suitable aslong as you were cruising down the expressway, but at city speeds, and temps it wasnt comftorable. If I hard wired my fan to run anytime the engine is running, woudl it make the A/C work better? Also, I bought some Freeze12, it is suppose to be a direct replacement for R-12. Any thoughts on this product? If worse comes to worse, I can run to Canada and get some R12 as it is still legal to buy there in the auto parts store. If I did swap to R-12 woudl I have to change all the swappee compnents back, or just the old recharge fitting? Thanks guys.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: A/C question (boxerlover79)
If you switch back, you will have to go through the same process you went through to change to R134. Good vent temps at speed, but less than ideal at idle can mean a couple of things. It may be overcharged. You only need about 80% of the R12 capacity with R134. It could be that the low pressure switch is set too high. For R12, the contacts will open at 25psi shutting off the compressor. For R134, you want it to cycle at about 22 psi. Adjust by turning the screw between terminals counterclockwise, a 1/2 turn or so. Did you get all of the old stuff out? A mixture of R12 and R134 raises system pressure and performance will suffer. If you're dead set on going back to R12, get your license at http://www.epatest.com or any of the sites listed at http://www.epa.gov. Then buy all the R12 you want - you'll need about 4 cans which was running $12 - $15 a can the last time I needed any. Should be cheaper now - not many cars left using it and those who think they are going to make a killing on it, let them continue to have their dreams. Autozone was the cheapest, but they may have finally depleted their inventory.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: A/C question (boxerlover79)
Fan switch on the high pressure line opens at 230 psi - turning on the fan and closes around 170 psi - turning the fan off. Those pressures are ideal for a/c operation so you might want to verify that it's working correctly by hooking up a manifold gauge set. Drop the high much below 170 and the low side will drop below the threshold for compressor engagement; ie, the low pressure switch is going to shut it off and a compressor that isn't engaged at idle, in hot weather, isn't going to produce very cool temps. You should check you're operating pressures and then determine what's best to make it right. R134 can produce good vent temps if the conversion is done correctly; maybe 5 - 10 degrees warmer, but still adequate.
