Parts for your 1991 Mitsubishi Pajero-Receiver driers

1991 Mitsubishi Pajero receiver-drier: what it does and when to replace it

Based on technical references including the Mitsubishi Pajero Factory Service Manual (1991, Heating & Air Conditioning section), the Mitsubishi ASA electronic parts catalogue for 1991 models, and general A/C system guides from DENSO for TXV-style systems, the 1991 Mitsubishi Pajero is fitted with a receiver‑drier in the high‑pressure liquid line. Those sources describe a thermal expansion valve (TXV) layout using a condenser, receiver‑drier, TXV and evaporator — so a receiver‑drier is absolutely relevant on this vehicle.

On this Pajero, the receiver‑drier’s job is straightforward but crucial. It stores and filters liquid refrigerant from the condenser and pulls out moisture using a desiccant pack. Moisture is the enemy of air‑con systems, it forms acids, corrodes components and can freeze at the TXV, causing weak or erratic cooling. The drier also traps fine debris to protect the TXV and compressor. It’s usually mounted up front near the condenser, often on the right‑hand inner guard, and may carry a pressure switch port.

As part of regular servicing, the receiver‑drier should be replaced any time the A/C system is opened, after a compressor or condenser change, following a leak, or when converting from R12 to R134a. On an older 1991 truck, the desiccant can simply age out, many tech bulletins recommend renewal every few years on high‑mileage or long‑stored vehicles. A tired drier can show up as slow pull‑down, fluctuating vent temps, or contamination found at component change.

• Always replace O‑rings with HNBR (R134a‑compatible) items and lubricate with the correct oil (mineral for R12, PAG/POE for R134a conversions).
• Evacuate the system with a vacuum pump to remove moisture before re‑gassing.
• If the old compressor failed, fit a new drier and flush lines/evaporator to get rid of debris.

Because refrigerant handling is regulated in Australia and New Zealand, the work should be done by an ARCtick‑licensed technician. They’ll pressure‑test, evacuate, charge by weight and verify TXV operation. Keeping the receiver‑drier fresh helps the Pajero’s air‑con cope with harsh Aussie and Kiwi summers and protects pricier parts like the compressor.

FAQs

Where is the receiver‑drier on a 1991 Pajero?
It’s typically mounted at the front of the vehicle near the condenser, commonly on the right‑hand inner guard or behind the headlamp area. Look for a cylindrical canister with two A/C lines and, on some models, a pressure switch.

How often should it be replaced?
Replace it whenever the system is opened, after major A/C repairs, or if the vehicle has sat unused for a long time. On an older 1991 system, proactive replacement every few years helps keep moisture and debris at bay.

Can a bad receiver‑drier damage the A/C?
Yes. A saturated or blocked drier can let moisture and particles circulate, leading to TXV icing, poor cooling and even compressor wear. It’s a cheap part that protects expensive components.