Model: F250 Super Cab
Engine Size: 351W
Refrigerant Type: r-134
Country of Origin: United States
I have a 1989 Ford pickup. The system was completely discharged when I bought the truck. I recently rebuilt the motor, so I decided to repair the A/C system as well. Here's what I've done to date:
Replaced the compressor, receiver/drier, and orifice tube.
The system had been converted to R-134 at some point in its life (110k+ miles on vehicle) - it had the low & high side fitting adapters.
I connected a set of gauges to it, and ran a vacuum pump on it for 1 hr. (needle on gauges was pegged at 30" vacuum)
I closed both valves on gauges and let it sit for 1 hr. - no loss of vacuum observed.
I charged the system with fresh R-134/oil charge, I used all three 12-oz. cans that were in the kit. The compressor was still cycling - each time it came on, the high side would build to 150, and the low side would drop to 25. The line going from the compressor to the condenser was hot, the line from the condenser to the orifice was "room" temperature, the tube going into the evap was cold and sweating, but not iced up, and the tube coming out of the evap was room temp. The inside vent in the center of the dash feels slightly cool, and the vent on the far right end feels like it's just the fan blowing. All of this is with the a/c on "max", fan on high, and slide lever all the way over on cool.
I bought an A/C manual that says this unit should hold 3.25 lbs. of refrigerant (I have since found the factory sticker - it was on the discarded receiver/drier - it says the system should hold 3.25 lbs. of R-12) As I had only put in 3 12 oz. cans of refrigerant, I thought it still was probably low, I added more refrigerant. The low side pressure comes up to 45 with the compressor off, but when the compressor comes on, the pressure drops slowly to 25, then the compressor cuts off. The high side pressure now comes up to 225-250, but the temperatures of all the lines are still as described above.
Does this indicate a blockage in the condenser, the line to the orifice, the orifice, or the evaporator?
How can I pinpoint the problem?
A few other things to note:
When I broke in the motor, the compressor was in stalled, but the electric clutch was not connected, and the lines were disconnected (I had plugged them when I disconnected them)
When I re-installed the lines/manifold on the new compressor, there was a plastic cover over the ports, and a rubber plug in the inlet side, which I removed. Was this a shipping plug, or was it a necessary part? When I installed the compressor, I left the plastic cover on, and rotated the compressor 12 turns with a wrench as instructed. When I pulled the plastic cover off to install the lines/manifold, oil squirted out of the compressor discharge port.
When I replaced the orifice tube, the old one was clogged up maybe 50% with some brownish/blackish gunk.
I can't find any troubleshooting chart that shows low low side pressure / high high side pressure.
Please help - thanks.
It sounds like the new version of Interdynamics death kit was used. This has 3 cans each containing 12 oz R-134a, 3 oz ester oil, and sealer. So now there's too much oil, and sealer in the system.
Check out the Flushing section of the board, as your system needs to be flushed, as soon as possible from what I read... here is link to the tips and FAQ page which has a lot of useful information on charging retrofits. Be sure your fan clutch is working properly, if you switched to electric fans, make sure they are blowing in the right direction. But isolate the compressor, flush it with fresh oil, flush the rest of the system, consider changing the condenser if you can, but get that sealer out..use new o rings, new oil, I recommend BVA auot 100 ester oil, new o tube, and you'll have to change the accumulator again as it will be contaminated with the old oil and sealers.. Use only virgin refrigerant and oil.. stay away from death kits, the stuff in them will void most warranties anyway..Hope this helps.
Freedoms just another word for nothing left to lose
Thanks for all the info, guys. Apparently the only thing I've done right so far is come to this forum for advice . Yes, the kit was the new Interdynamics "Death Kit" I'll check out the tips & FAQ page. You have an excellent forum here, and I appreciate the fast response.
Actually, you did a number of things right*, it's just that A/C has to be 100% right. Even 90% is not a passing grade in this area ;-)
1) You used a proper manifold gauge set with low AND high side gauges. How many times do we see a user report only the low side pressure because that's what the gauge on their death kits displays?
2) You had the sense to change the orifice tube
3) You replaced the receiver-drier (Isn't that an accumulator system?) - unfortunately, you'll now need to replace it again after you flush the system
4) You pulled a vacuum on the system and made sure it held. Plenty of newbies fail to do even this.
See, it's not all bad....but it's subject to the rule that one "oh $hit" cancels 10 "atta boys". At least now you'll be on the right track to fixing it right.
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