Automotive Air Conditioning Information Forum

Mark86 wrote: ↑Mon Feb 13, 2023 1:17 pm As for the TXV, this wouldn't be the first time I've heard about a "new" TXV malfunctioning. Causes include loss of gas in the sensing bulb.
- good point. I’ve been burned by “new” parts more often than I like. I have the old TXV and may bench test it for an idea if it was working or not.

Mark, it seems like we've covered everything else except changing-out the TXV again.

I've never attempted to test one on the bench. Normally, I replace it with a new OEM part, if available. Just guessing, but you might be able to see the internal needle move a little bit as you warm and cool the sensing bulb, alternating between a hair dryer and an ice-in-water solution. Put a little mark on the needle with a Sharpie to help with that. If you can see any needle movement, then the bulb and capillary tube have gas in them and the valve is probably good. You might also have to pressurize the equalization tube for this test to work.

If someone in the past had attempted to adjust the superheat spring, then it might be out of calibration, though.

I’m going to start with a new Rec/Drier. This problem has followed two TXV and Evaporators. The constant is the R/D. Then if problem persist, I will order an OEM TXV and install that. I’m back to work for a few days so I will update when I get the new R/D in.
Thanks again.

You can also alternate between a hair dryer and a can of so-called computer air which has a very cold spray, to the point it can even frost up an object

Mark86 wrote: ↑Tue Feb 14, 2023 4:28 pm I’m going to start with a new Rec/Drier. This problem has followed two TXV and Evaporators. The constant is the R/D. Then if problem persist, I will order an OEM TXV and install that. I’m back to work for a few days so I will update when I get the new R/D in.
Thanks again.

Mark, I didn't re-read the entire thread, but I believe that this would be the third R/D if you change it out again. It's possible that it is defective—for instance, the internal screen could be plugged or partially plugged for some reason not known to us—and it won't hurt anything to replace it. Of course, you'd have to recover the refrigerant, then evacuate and recharge the system again. A new R/D is also relatively inexpensive, as you probably know.

If the system works correctly after the change-out, it would be interesting to see what the insides of the previously installed R/D look like. It's easy to cut it in two using a 4-1/2" angle grinder and a thin-kerf abrasive cut-off wheel. Be sure to wear eye, ear, and hand protection while doing the cutting.

Not sure how many R/D it has had in its life with the multiple repair attempts. Under my repair I initially installed a new Comp, R/D and Condenser, so just 1 RD.

Noticed the diving and constant cycling. I was on the fence about tearing into the dash if not needed, but went ahead and replaced the Evap and TXV as I had a TXV and Evap on the bench. Replaced those and the diving LP issue persists.

My thoughts are there are only two items that can constrict the flow, TXV or a blocked / bad R/D. I inspected the lines for kinks or bends, blew them down and they flow freely. There is only about 3 feet of rubber hose, the rest Al pipe.

I’ve chased my tail before due to bad or faulty “new” parts. Maybe the R/D wasn’t sealed and it sat in a CONEX container for 6 months and the desiccant is now one solid piece.

I've skimmed most of this thread. Doesn't sound like compressor problem, the compressor pulls down to an adequate suction pressure. 2nd capillary tube from the TXV would be an external equalizer connection, must be hooked up to the suction pipe at evaporator out.

You might be getting replacement TXVs that fit many applications, but are not adjusted for your Montero. Poor vent temps, but with proper suction pressures might be too high superheat (TXV needs adjustment). Also might be a heater core blend door problem, not sure if you've investigated that already.

DetroitAC wrote: ↑Thu Feb 16, 2023 5:24 am I've skimmed most of this thread. Doesn't sound like compressor problem, the compressor pulls down to an adequate suction pressure. 2nd capillary tube from the TXV would be an external equalizer connection, must be hooked up to the suction pipe at evaporator out.

You might be getting replacement TXVs that fit many applications, but are not adjusted for your Montero. Poor vent temps, but with proper suction pressures might be too high superheat (TXV needs adjustment). Also might be a heater core blend door problem, not sure if you've investigated that already.

The TXV is non adjustable, and was identical in physical appearance to the one removed (which was a replacement as well).

The Comp engages, LP needle begins to dive until LP switch cut off. Rinse and repeat.

I did have an up close look at the blend door, seals, and function when the evaporator housing was removed. All normal Ops.

As mentioned going to replace the R/D then the TXV with an OEM unit. Although I’ve ordered OEM from the dealer in a “GM” or Delco box only to find it’s the same aftermarket part I had.

I've never seen a TXV that isn't adjustable, manufacturing tolerances require them to be adjustable, It sounds like an angled brass unit if it has an external equalizer. Adjustment is a hollow screw, usually a hex screw that is just a ring, inside the outlet port ( inline with the pin that goes from the power head to the ball or cone)

Agree.
Too bad they are not externally adjustable as they are on resi and commercial

Mark86 wrote: ↑Thu Feb 16, 2023 1:59 pm As mentioned going to replace the R/D then the TXV with an OEM unit. Although I’ve ordered OEM from the dealer in a “GM” or Delco box only to find it’s the same aftermarket part I had.

Interesting about the "GM" TXV. One tip-off that it's a true OEM component is that it will probably cost three or four times as much as an aftermarket TXV. In my humble opinion, it's money well spent if you can locate one.

Isn't the OEM TXV for your Mitsubishi a Denso part? Regardless, have you checked with Tim at ACKits.com, this Forum's sponsor, to see whether he has one in stock or can get it for you?