When I turn on the a/c, the compressor goes on (clutch engages) for a few seconds, then shuts off, on a few seconds, shuts off ... repeat forever. Any one know what is going on?

Thanks - Chris

 

Add refrigerant and see if it stops.

 

Sounds like you are low on Freeon(sp?) Before you put Frigerent read this

all a/c systems before 1995 use a Frigerent called R-12 which you can't buy less you have a liense to buy and right now I think it is $60 a can

1995 and later use 134-A which you can buy at wal*mart or part stores.

You can convert a R-12 A/C system to 134-A but all of the r-12 Freeon(sp?) must be vacumed out of the system

 

If adding freon doesn't solve this, take a paper clip and jumper across the electrical connector for the high/low pressure switch. It's usually located on the accumulator. If the compressor continues to run when you jumper the switch, you could have a bad high/low pressure switch.

 

Thanks for the help. The coolant is low. I'm checking for leaks with the dye. Added a little coolant and problem went away.

Thanks for the help

 

hi

i think i have the same probelm as this. My 1990 f250 a/c has stopped working i checked the pressure in the system and its fine. I do however have a strange noise from the compressor which clicks on and off all the time when the truck is running regardless if the ac is switched on or off...

is there anything i can do to fix the a/c or do i need to change to the new setup?

 

What happens if you put '134-A' in a 'R-12' A/C system???

 

The oil that is in an R12 system is not compatible with R134 freon. I don't know exactly what the outcome would be, but you would probably ruin the whole system. I converted mine from R12 to R134, the first time, in 1998 when my compressor failed and just redid the system with another compressor this past summer. R134 uses a different oil. I changed out the compressor, flushed the lines and condensor and installed a new accumulator with expansion valve. You need a set of gauges, an air compressor and a vacuum pump to do all this. And above all you need to research it and be careful. The whole conversion with a new compressor from Advance or Autozone would run about $350 or so.

 

Once the A/C system is opened up, you need to remove all of the regular air and moisiture in the system with a vacuum pump before filling with R-134. You can buy a decent vaccuum pump for $150. I'm wondering if anyone has tried those cheapie $50 vauum pumps that connect to shop air? Do they work?

A purge and filling from my local shop costs $125 so I thought I might try it myself...

 

I got a vacuum pump at Harbor Freight for $10 that I and several people I work with have used and it works fine. The more expensive ones are nice, but to use once a year, maybe, that 's a lot of money to just let sit around.
It works off an air compressor or shop air either one.

 

Boy I love these forums. I've had this problem for about a year now and I figured the compressor was going. The air that comes out is still cold and this clicking reminds me of the compressor dying in my old truck (82 F150). I was just figuring on replacing the compressor once it died. Thanks guys.

 

Ok - I'll try the $10 vacuum pump. Does it need a large amount of air flow to work? All I have is one of the compact "pancake" compressors.

 

O.K. I was wrong the price went up to $15.99 now. But that still beats $150.
This link is to the page showing the pump. Says it requires 4.2. CFM. I used a 5 HP compressor with a 20 gal. tank and it worked fine. Depending on how hot it is you might want to increase the time you pull the system down with a minimum of 45 min's. I think I pulled mine down for an hour and it was about 90 degrees. Might want to set your air compressor in the shade also, if it gets too hot it may kick off. The threads on the vacuum pump are set up for an R12 hose connection so you will need to by an R12 to R134A adapter somewhere like NAPA. The adapter will cost as much as the vacuum pump did.
A set of R134A gauges is a must for doing this. They are $50 at Harbor Freight.
http://www.harborfreight.com/cpi/cta...temnumber=3952

 

Thanks for the help guzzler96,

Thats just what I did. Ordered the pump and gauges at harbour freight. I'll pick up the adaptor when I buy the R134.

 

My '94 F150 5.0 v8 came with R134a from the factory and still blows ice cold.