Parts for your 1987 Mitsubishi Pajero-Heater tap

1987 Mitsubishi Pajero Heater Tap — what it does and how to keep it happy

Referencing the Mitsubishi Pajero/Montero 1983–1991 Workshop Manual (HVAC Group) and the Mitsubishi ASA electronic parts catalogue for the L040 series, the 1987 Mitsubishi Pajero is fitted, in most market configurations, with a heater water control valve — commonly called a heater tap — on the heater hose at the firewall. Those factory sources show a cable- or vacuum-actuated tap controlling coolant flow into the heater core.

The heater tap’s job is simple but important: it meters hot engine coolant into the heater core so the cabin gets warm air when the slider’s on “hot”, and reduces or shuts flow when set to “cold”. On a tough old Paj, a healthy tap means better demisting on cold mornings, steadier cabin temps, and less unwanted heat soak through summer.

• Common symptoms of a crook heater tap: stuck on full hot or no heat, a stiff or gritty control lever, coolant seepage at the tap body, the sweet smell of coolant, or slow coolant loss without obvious drips.
• Typical location: high on the firewall, passenger side, in-line with the two heater hoses, actuation via a cable from the dash slider, or vacuum hose on some specs.

Good servicing practice for an ’87 Pajero is to inspect the heater tap whenever the cooling system is checked. Look for perished hoses, rusty clamps, green crust around the tap spindle, and free movement from cold to hot at the dash. A couple of drops of silicone-safe lubricant on the cable end won’t hurt. If the tap binds, leaks, or refuses to shut off/on, replacement is the go — they’re inexpensive and save the heater core from contamination.

1. Only work on a stone-cold engine. Drop coolant to below firewall level (about a few litres) via the radiator drain.
2. Mark hose orientation, remove clamps and hoses, disconnect the control cable or vacuum line, then lift out the tap.
3. Fit the new tap in the same flow direction (look for the embossed arrow). Renew any tired hoses and clamps.
4. Adjust the cable so full “hot” at the dash equals full open at the tap, and “cold” equals fully closed.
5. Refill with the correct coolant mix, bleed air, and check for leaks with the heater set to hot and the engine at operating temp.

That little valve does a lot of work in Aussie and Kiwi conditions, keeping it tidy helps the Pajero stay comfy and the cooling system reliable.

Popular questions about 1987 Mitsubishi Pajero heater taps

Where exactly is the heater tap on an ’87 Pajero?
It’s typically mounted on the passenger-side firewall, in-line with the upper heater hose. Look for a small lever and cable, or a vacuum nipple, between the two rubber heater hoses that pass through the firewall to the heater core.

How can someone test if the heater tap is working?
With the engine warm, move the cabin control from cold to hot and watch the tap lever move. Both heater hoses should get hot on “hot”, on “cold”, the outlet hose should cool off relative to the inlet. If the lever doesn’t move or the temperature doesn’t change, the tap or cable may be faulty.

Do all 1987 Pajeros have a heater tap?
Most first-gen Pajeros do, as shown in Mitsubishi’s workshop and parts literature, but some market/trim variations used different actuation. If yours has constant hot hoses and no valve body at the firewall, it may be a constant-flow setup using an internal blend door instead.