Parts for your 1991 Mitsubishi Pajero-Head gasket

1991 Mitsubishi Pajero head gasket — what it does and how to look after it

Technical sources confirm the 1991 Mitsubishi Pajero uses a cylinder head gasket, so the part is absolutely relevant to this model. References include: Mitsubishi Pajero/Montero/Shogun Workshop Manual (1991, Engine Mechanical – Cylinder Head), Mitsubishi Motors 4D56 Diesel Engine Service Manual (head gasket thickness and torque procedures), Mitsubishi 6G72 V6 Engine Manual (cylinder head and gasket replacement), and common aftermarket manuals such as Haynes and Gregory’s for 1983–1997 Pajero models. These manuals detail the gasket’s function, torque sequences, and replacement specs for engines fitted to 1991 Pajeros, including the 2.5L 4D56 diesel and 3.0L 6G72 V6.

On their 1991 Pajero, the head gasket seals the join between the engine block and the cylinder head. It keeps combustion pressure in the cylinders while keeping oil and coolant in their own passages. When it’s healthy, the engine runs crisp, stays cool, and doesn’t drink fluids. When it fails, owners can see overheating, rough running, and cross-contamination of oil and coolant.

It’s not a routine “replace by kilometres” item — it’s replaced if it fails or when the head is off for other work. That said, smart servicing helps it live a long life:

• Maintain the cooling system: fresh coolant per the manual, a healthy radiator cap, clean radiator, working fans and thermostat. Overheating is the head gasket’s worst enemy.
• Use proper torque and sequence: if the head ever comes off, follow the factory tightening order and angle stages. On 4D56 and 6G72 engines, use new head bolts as specified.
• Check the head and block: have the cylinder head pressure-tested and skimmed if needed, make sure surfaces are clean and flat before fitting a new gasket.
• Choose the correct gasket: thickness and material (often MLS for later service replacements) must match the engine’s spec and measured protrusion/clearance.

Signs they shouldn’t ignore include sweet-smelling white exhaust, unexplained coolant loss, creamy residue under the oil cap, hard upper radiator hose from cold, overheating on climbs, and bubbles in the expansion bottle. If these crop up, it’s time for a compression test, leak-down, and cooling system sniff test. A proper repair means the right gasket, new bolts where required, correct torque procedure, fluids renewed, and rechecking for leaks after a few heat cycles. Done right, a Pajero head gasket can go the distance across Aussie and Kiwi roads and tracks.

Popular questions about 1991 Mitsubishi Pajero head gaskets

How long should a 1991 Pajero head gasket last?
With a healthy cooling system and sensible driving, many go well past 200,000 km. Heat stress is the big killer, so keeping coolant fresh and temperatures stable is key to longevity.

Can they drive with a slightly blown head gasket?
Not recommended. Even a “minor” leak can escalate quickly, risking overheating, warped heads, and bottom-end damage. Best to diagnose early and plan a repair before it snowballs.

Do the head bolts need replacing on these engines?
Yes, on common 1991 Pajero engines like the 4D56 diesel and 6G72 V6, factory procedures specify new cylinder head bolts and angle-tightening. Reusing old stretch bolts risks poor clamping and repeat failure.