Parts for your 1987 Mitsubishi Pajero-Tx valve

1987 Mitsubishi Pajero TX Valve — what it does and when to service it

Yes, a TX valve is relevant to the 1987 Mitsubishi Pajero. Technical sources including the Mitsubishi Pajero/Montero 1983–1991 Factory Service Manual (Group 55: Heating & Air Conditioning), the Mitsubishi ASA Electronic Parts Catalogue for L040-series Pajero, and aftermarket catalogues from DENSO and Four Seasons all specify a thermostatic expansion valve (TXV) fitted at the evaporator on this model. Being an R12-era system from factory, it uses a receiver–drier and a TXV rather than an orifice tube/accumulator setup.

On a first-gen Pajero, the TX valve meters refrigerant into the evaporator based on temperature sensed by its bulb and the pressure returning from the evaporator outlet. By controlling superheat, it keeps the evaporator cold without flooding it, which means steady cabin temps, decent pull-down on hot days, and protection for the compressor.

When servicing the A/C, the TX valve is worth a look any time the system’s open or performance is patchy. Common give-aways it’s unhappy:

• Airflow is fine but cabin cooling is weak or swings hot–cold.
• Frosting at the evaporator or valve body, with low suction pressure.
• High head pressure and a noisy, overworked compressor.

Replacement is a straightforward, glovebox-out job on most Pajero trims, as the valve sits at the evaporator connections near the firewall/behind the dash. Because refrigerant work is regulated across Australia and New Zealand, recovery, evacuation and re-gassing must be handled by a licensed A/C technician.

Good practice when replacing the TX valve on a 1987 Pajero:

• Always fit new O-rings compatible with the chosen refrigerant and oil.
• Replace the receiver–drier whenever the system’s been opened.
• If converting from R12 to R134a, use a R134a-specified TXV and oil, flush out mineral oil, and label the vehicle clearly.
• After assembly, pull a deep vacuum, verify it holds, then charge to the correct weight rather than by pressures alone.

Look after the TX valve and the Pajero’s A/C will pull its weight from the coast to the high country. If performance is still off after a valve swap, consider blower speed, blend doors, condenser cleanliness, and fan operation—they’re all part of the same comfort equation.

Popular questions

Where is the TX valve on a 1987 Mitsubishi Pajero?
It’s mounted at the evaporator inlet/outlet, typically behind the glovebox or at the firewall interface. Access usually involves removing the glovebox liner and trim to reach the evaporator pipes and valve body.

Should the TX valve be changed during an R134a conversion?
It’s strongly recommended. Fit an R134a-compatible TXV, replace the receiver–drier, update O-rings, and switch to the correct oil. This helps stabilise superheat and prevents hunting or poor cooling with R134a.

How can they tell it’s the TX valve and not just low gas?
Low refrigerant typically shows low suction and low discharge pressures with weak cooling. A sticking or misadjusted TXV can show low suction but normal-to-high discharge, frosting at the valve, and cycling temps. Proper diagnosis with gauges and temperature probes by a licensed tech will confirm it.