Parts for your 1987 Mitsubishi Pajero-Heater core

1987 Mitsubishi Pajero Heater Core: What it is, and how to look after it

Based on technical sources, the 1987 Mitsubishi Pajero is fitted with a heater core (also called a heater matrix) as part of its HVAC system. This is documented in the Mitsubishi Pajero/Montero Factory Service Manual (1983–1991) under Heating & Ventilation, the Mitsubishi ASA/CAPS electronic parts catalogue listing for the heater unit and water cock, and independent manuals such as Haynes and Gregory’s for 1983–1991 Pajero models. So, the heater core is relevant to servicing and ownership of a 1987 Pajero.

On a first‑gen Pajero, the heater core is a small radiator tucked inside the heater box behind the dash. Engine coolant flows through it, a fan pushes air through its fins to warm the cabin and clear fogged glass. Depending on market spec, there may be a cable‑operated heater tap on the firewall, or the core may have constant flow with a blend door managing temperature. Either way, it’s a key bit of kit for demisting, winter comfort, and general drivability in Aussie and Kiwi conditions.

Keeping the core happy really comes down to cooling system care. Old coolant turns corrosive, silts up the core, and invites leaks. Owners should stick to regular coolant changes (typically every 2 years or as per the service manual), use quality ethylene glycol coolant mixed to climate, and flush both the radiator and the heater circuit. Back‑flushing the heater core through the firewall hoses can restore heat output if it’s partially blocked. Fresh hoses, proper spring‑band or quality screw clamps, and a tidy heater tap are cheap insurance on an ageing Gen‑1.

• Common failure signs: sweet coolant smell in the cabin, greasy film on the windscreen, fogging that’s hard to clear, damp carpet under the dash, or unexplained coolant loss.
• Good practices: run the heater to full hot during bleeding, replace the radiator cap and thermostat if they’re long in the tooth, and check for electrolysis if leaks keep returning.

Replacement is doable at home but is fiddly. Expect several hours: disconnect the battery, drain coolant, clamp and remove the heater hoses at the firewall, then pull trim panels and the heater box to access the core. Swapping the core is straightforward once the box is out, fit new foam seals and O‑rings, pressure‑test the assembly if possible, then re‑install. Refill with the correct coolant mix, set the heater to hot, and bleed all air. Many take the chance to replace the heater tap and all heater hoses while they’re in there.

Dash layouts and air‑con hardware vary by year and market, so following the factory manual steps for the specific trim is the best path to a neat, rattle‑free result.

Does a 1987 Pajero actually have a heater core?

Yes. Factory manuals for 1983–1991 models, the Mitsubishi electronic parts catalogue, and mainstream repair guides all show a dedicated heater core and related bits (heater tap, hoses, and heater box). It’s standard equipment on first‑gen Pajero/Montero/Shogun models.

How can an owner tell if the heater core is leaking?

Typical clues include a sweet coolant smell inside, an oily haze on the windscreen, damp carpet on the passenger side, or steady coolant loss with no obvious external drip. Some hear a faint gurgle behind the dash. Persistent fogging on cold mornings is another giveaway.

Can the heater be bypassed temporarily?

In a pinch, yes. Joining the two heater hoses at the firewall will keep the vehicle mobile and stop an in‑car leak, but the cabin will have no heat or demist. It’s only a stop‑gap, the proper fix is repairing or replacing the core and any tired hoses or the heater tap.