I see Detroit's point on sequestering liquid refrigerant, but that can get pretty complicated. I don't like solenoid valves in refrigeration if I can avoid it. Lessons from the SAAB. I had a little over 6 gallons of chiller liquid in a tank, concealed in an ice chest in the back. A decent pump and i...

Ok, let's sort out the OEM components from the changes first. The original Front / Rear GM system had a hard line from the condenser with a T in it to feed the rear evaporator TXV. It did not include a receiver / dryer for the rear TXV, but relied on the 8 feet of line to the back of the vehicle for...

Detroit has a great point about the drive ratio issue. Had an Explorer that was miserable unless you manually shifted it to keep the engine speed above 3200rpm And the auto trans was shifting at 1300 all the way to OD around town. I gave up and put 4.56 gears in both ends of it. Try driving your Lex...

With the Lexus part of the blame goes to the NVH engineers. Can't have all of that blower noise in a luxury vehicle. God forbid you ever hear a refrigerant gurgle... Overwhelmed system will keep pumping to the HPCO range. So let's say you have 375 psi liquid headed for the expansion device. That wou...

Where did you source the replacement coil?

These were more fun

You seem to have a good sized leak. Be sure to check your gauge hoses, adapters, manifold valve stems etc for leaks. Nothing worse than bringing the leak with you to the car... Regarding the static system test pressure. A 134a vehicle in the sun in Phoenix is well over 160 psi just with the refriger...

Detroit: In my experience those evaporators do a fine job. Plenum works just fine on big GM vehicles. Tim: Not just a front only A/C in a Suburban on 134a... The suction will drop all the way to 21 psi! Seriously, the normal suction on a system like at at idle can be as high as 60 psi depending on a...

One other thing to check, since it will run as low as 25 psi on the low side...

Run it above 1500 rpm for a little bit, and look at the accumulator. Does it have a frost line? Is if half full of refrigerant?

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Should be a block style TXV on that truck. The BCM is involved in the A/C operation. Sunlight sensor, Outside air temp sensor, ETC. If the compressor is running and it is not very cold it could be a TXV. But since you state the compressor cycles off, one or more sensors are involved. A scan tool mig...