Parts for your 1987 Mitsubishi Pajero-Oil cap

1987 Mitsubishi Pajero Oil Cap — What it does and how to look after it

The 1987 Mitsubishi Pajero absolutely uses an oil filler cap. This is shown in Mitsubishi’s Factory Service Manual for the 1982–1991 Pajero (Engine — Lubrication section), identified as “Cap, Oil Filler” in Mitsubishi Motors’ ASA electronic parts catalogue for the L040-series Pajero (covering both 4G54 petrol and 4D56 diesel engines), and noted in the owner’s handbook procedures for topping up engine oil. So, the oil-cap is a relevant, fitted component on this model.

On a ’87 Pajero, the oil cap screws into the rocker/valve cover and does more than just give a place to pour oil. It seals the engine’s top end to keep dust, grit, and water out, helps manage crankcase pressure as part of the ventilation system, and stops oil mist from weeping under the bonnet. A healthy cap (with a soft, intact rubber gasket) helps keep the engine bay tidy and reduces the chance of odours or minor leaks. If the cap is missing or damaged, oil can splash out and unmetered air can enter, which can upset idle quality on petrol engines and make a mess on both petrol and diesel setups.

As part of routine servicing every 10,000–15,000 kilometres (or as per the oil change interval used), the oil cap deserves a quick once-over. Wipe around the filler neck before removing it so no debris drops in. Check the cap’s gasket for hardening, flat spots, or cracks, inspect the threads for damage, and make sure it tightens smoothly to a firm, positive stop without needing to be forced. If the cap feels loose, seeps oil, or the gasket has gone hard, replacing it is inexpensive insurance.

• Clean the area, then remove the old cap and gasket.
• Lightly oil the new gasket with fresh engine oil.
• Screw the new cap on by hand until snug — no tools, no over-tightening.
• Run the engine and check for any weeping around the cap after a short drive.

Genuine or high-quality aftermarket replacements are both fine — just match the engine family (4G54 or 4D56) so the thread and seal profile are correct. It’s a small part that quietly protects a big investment.

Technical references: Mitsubishi Pajero 1982–1991 Factory Service Manual (Engine — Lubrication), Mitsubishi Motors ASA Electronic Parts Catalogue for L040-series Pajero (lists “Cap, Oil Filler” for 4G54/4D56), Haynes Repair Manual for Mitsubishi Pajero/Montero 1983–1996 (Engine chapter).

Popular questions about 1987 Mitsubishi Pajero oil caps

Where is the oil cap on a 1987 Pajero?
It’s on the top of the engine’s rocker/valve cover. On the 4G54 petrol, it’s typically centred or slightly offset on the alloy cover, on the 4D56 diesel, look for the screw-in cap on the pressed or cast cover. It’s clearly marked for engine oil.

What are the signs an oil cap needs replacing?
Common clues are oil mist around the cap, a brittle or flattened gasket, a cap that won’t snug down, or a noticeable oil smell after driving. On petrol models, rough idle from a minor air leak can also show up if the cap isn’t sealing properly.

Can any Mitsubishi oil cap fit a 1987 Pajero?
Not always. While many Mitsubishi caps look similar, thread and gasket profiles vary. It’s best to choose a cap specified for the 4G54 petrol or 4D56 diesel used in 1987 Pajeros, or use a genuine part matched by VIN or engine code.