Pro6TEN issues.

[Awann99]

I recently converted my 72 k2500 to orginal AC using r134. I used a new Pro6Ten A6 compressor. Vintage air Parallel flow condenser annd drier. Everything thing else is new expect the evap core and POA valve which was changed to 27 psi.

I charged it with around 3 and half 12 oz cans of r134

My low side pressure is 55 high side is 250

It's blowing around 50 degrees.

It's 78 degrees outside with 85% humidity when I took these readings

The compressor needs to be super tight and then it still starts to slip after a few minutes. The belt size looks a little too wide at the top causing this. I'm going to get a 13/32 size belt and see if it helps.

Currently I can smell and see the belt getting burnt up when it slips.

So my question is does this sound like a failing compressor or just a belt squeal. Did I over fill the ac based on these readings. I feel like it should be colder.when the belt slips I can feel the compressor is hot to the touch. The only thing cold on the system is the POA line and evap core. It is sweating.

I also added 8 oz of PAG oil to the system before adding the r134.

Any help would be great. Thanks.

[Bob B.]

Low side should be somewhere around 25-35 psi, high side maybe 175-200 psi at that temp.. Check to see if the pipes into and out of the evaporator are both cold, close to the same temperature. You may be a bit overcharged or you may have poor air flow through the condenser, that will cause both the high and low sides to be higher than normal. 50 degree output isn't bad, you are seeing a 35 degree reduction in temp.. Doesn't sound like the compressor is giving up, just the pressures are too high and the belt is slipping. You have plenty of oil in it.

[Awann99]

Awesome. Thanks Bob. Both pipes coming out of the evap core were very cold. The compressor also pulls my rpm's down about 200 when at idle. You can really feel the HP pull when I'm driving. Turning it off when I'm
Driving feels like I'm letting off the brakes. Is that normal? This is the first truck I've driven with ac.

[Bob B.]

A little bit maybe, but not much. My truck idles a bit slower with the A/C on, but I really can't feel it while driving.

[jeffahart]

Originally Posted by Awann99

Awesome. Thanks Bob. Both pipes coming out of the evap core were very cold. The compressor also pulls my rpm's down about 200 when at idle. You can really feel the HP pull when I'm driving. Turning it off when I'm
Driving feels like I'm letting off the brakes. Is that normal? This is the first truck I've driven with ac.

Yes. I just ditched my Pro6ten for an SD7H15 Compressor. I used Alan Grove Brackets. My Pro6ten on r134 was cooling fine. But I hated it dogging my engine, especially when it's hot. And it gets really hot here. When hot, I could not switch the A/C on at running RPM or the belt would not grab and start squealing. I had to put my foot on the gas pedal a bit at idle or the RPM dropped too low; so I installed a solenoid on the carb to bump the idle when the A/C was turned on. But that does nothing for the belt squealing. And it still felt like I was towing a load with the A/C on.

So, I moved to the SD7H15 with the Alan Grove brackets. I drove it at temp of 114 and measured 49 at side and center vents(on r134) no more engine dogging and I just pulled the compressor snug and tightened to bolts... no more belt slippage and squealing. It is a joy to have this setup. I need A/C here and I am now happy .

j

I will add, I just did the conversion over the winter. Been driving the truck a lot this summer, which I usually did not do because I hated the A/C compressor dogging my old engine. So far so good, no issues. I think this may be the best upgrade I've done on this truck!

j