A/C compressor question

[steve_kibbe]

I'm finally to the point I want my a/c to work.
When I turn the a/c on, the compressor clutch engages for a few seconds, then disengages for a few seconds, then engages and continues to disengage then re-engage.

My question: Is this normal? I know I have to recharge the system, there is pressure in the system from the compressor, but it seems wierd with all the engaging and disengaging.

TIA

 

[HarryH3]

That is a sure sign that the gas pressure is too low. The compressor switches on, but as soon as it starts pulling from the low-side the pressure on that side drops enough to trigger the low-pressure-cutoff switch. Once you properly fill the system it should work fine.

 

[steve_kibbe]

Thanks
Thats what I need to know.

 

[cbbr]

Mine needs 3-4 cans when it starts that.

 

[steve_kibbe]

I got the r-134 change over kit and I have air now

 

[HarryH3]

A/C is a wonderful invention! (It's currently 102 degrees outside here, yet my toes are cold...)

 

[southernspeed]

I got the r-134 change over kit and I have air now

Was the kit a tin of catalist and new valves?
I've just had that done to mine but I was very sceptical that it was so easy. You used to have to change the accumulter and all o rings etc.

 

[steve_kibbe]

The kit I got had 3 12oz cans that contained r-134, oil lubercant, and a leak sealer. I had to install the 2 new fittings, one over the high pressure port, and one over the low pressure port. Once those were installed, it came with a trigger type screw on nozzle and you just fill it to 85% capacity, which is .85x 3.25lbs for my system. It also came with a insturctional dvd that actually had a 91 blazer for a example

 

[steve_kibbe]

Oh, the wifey loves the new a/c too

 

[southernspeed]

Sounds a bit different from the one he put in mine. Time will tell! At the moment though it only works for 10 mins before the clutch won't pull in anymore, but it looks like when I had the unit off for a motor rebuild I set it up with WAY too much air gap...and now I can't get the thing to budge! Oh well....rock'n'roll!

 

[cbbr]

If you don't replace the accumulator and orifice tube filter, and clean out the system completely, and draw it down before putting the 134 in, you are just asking for black death.

 

[steve_kibbe]

Black death??

 

[cbbr]

Compressor gets full of sh!t and blows....

 

[K5er4Life]

and if it doesnt the a/c wont work for sh*t, people wonder why there 134 conversions dont net near the same results as the old r-12. You have to replace accumulator-drier, there is dessicant in there to filter the water and anytime the system is opened for repair it has to be flushed (to remove all the r12 compatible oil, cant mix r12 oil and r134 PAG oil) then a vaccum must be applied to the system. Also is a good idea because there are 2 different types of dessicant, xh7/xh9 which is for 134 systems and xh5 (for r12 systems). To do it properly it wouldnt be a bad idea to do a little book reading. You can have a shop flush and pull the vaccum, and even charge it if you dont have the proper gauges. If done correctly your a/c will last a long time and work effeciently.

 

[goldwing2000]

and if it doesnt the a/c wont work for sh*t, people wonder why there 134 conversions dont net near the same results as the old r-12...

In addition to all that, R134 isn't as efficient a refrigerant as R12 was. R134 requires a larger evap and cond, so any system that was designed for R12 won't ever be as cold once it's converted, even if it's done properly.

Dam you, Dow chemical... dam you to hell.

 

[steve_kibbe]

I'm just glad its blowing cold air

My wife was sitting in my blazer yesterday afternoon, and she said she was getting cold... it was in the mid 90's when she said that with the blazer sitting in the sun.

 

[K5er4Life]

women are cold blooded anyways. But hey if its staying cold sitting still and in that temperature then I would be more than happy. My system built up so much pressure sitting still that it purged 134 from the pressure release valve on the back of the compressor. I was out in the desert in about 100 degrees heat, letting the truck "cool down" while I was throwing in the last of what I had at camp to go home and all of sudden I hear a pop and see white-ish smoke bellowing out from under the hood. Scared the hell out of me, I thought my truck was going to blow up. Turns out that there is an elecric fan thats supposed to come on whenever the compressor switch is on. I wasnt getting enough air through the condensor and the system built up too much pressure and boom, there it went. Purged all of my freon into the atmosphere.

I have been thinking about getting a newer model compressor, condensor, and retrofitting it into my truck in hopes that it will cool better. But I dont know if I should because Im afraid that the orifice tube or something else in the system may not be "compatible" with the compressor condensor. What about just a bigger/more efficient condensor only? I bet that would be much better for the 134.