Parts for your 1998 Mitsubishi Pajero-Manifold gasket

1998 Mitsubishi Pajero manifold-gasket — purpose, fitment and servicing

Technical sources confirm a manifold-gasket is absolutely used on the 1998 Mitsubishi Pajero. The Mitsubishi Pajero/Montero Workshop Manual (1991–1999, Engine Overhaul), the Mitsubishi ASA electronic parts catalogue for the V20-series Pajero, and general repair references like the Haynes Mitsubishi Montero/Pajero manual all list both intake manifold gaskets and exhaust manifold gaskets for the 4M40 2.8 diesel and the 6G72/6G74 V6 petrol engines. So the manifold-gasket is relevant to this vehicle.

On a 1998 Pajero, the manifold-gasket seals the join between the cylinder head and the manifold. There are two types in play: the intake manifold-gasket keeps unmetered air from sneaking into the engine, preserving stable idle, correct air–fuel ratios and smooth running. The exhaust manifold-gasket contains hot exhaust gases as they leave the head, protecting nearby components and helping the oxygen sensor and turbo (on 4M40) see consistent flow. Either way, the gasket’s job is to hold pressure and temperature without letting leaks form as metals expand, contract and vibrate under the bonnet.

Age, heat cycling and surface corrosion are the usual culprits when a gasket gives up. On the diesel 4M40, EGR soot and oil mist can cake around the intake ports, hardening the gasket and creating air leaks, on the V6s, repeated heat soak can flatten the exhaust gasket. Typical tell-tales include:

• Ticking sound on cold start (exhaust leak) or a whistling/hiss (intake leak)
• Rough idle, loss of torque, increased fuel use, or diesel smoke changes
• Soot marks at the exhaust flange or vacuum/idle fluctuation at the intake

Servicing advice for a Pajero manifold-gasket is straightforward. Replace, don’t reuse. Clean both mating faces until spotless, check for warping with a straightedge, and follow the factory torque values and tightening sequence from the Pajero workshop manual. Quality matters—use genuine or OEM-grade multi-layer steel (exhaust) and composite/metal-backed (intake) gaskets. On 4M40 diesels, it’s smart to de-coke the intake runners and EGR passages while the manifold is off, that helps the new gasket seal properly and restores breathing. After refit, recheck fastener torque after a few heat cycles if the manual permits. For prevention, keep an eye on manifold nuts/studs, fix any broken studs promptly, and address misfires or over-fuelling that spike exhaust temps. With proper install and hardware in good nick, a fresh manifold-gasket should last for many years and kilometres in Aussie and Kiwi conditions.

Popular questions about 1998 Mitsubishi Pajero manifold-gasket

How can someone tell if the manifold-gasket is leaking on a 1998 Pajero?
Common signs include a sharp ticking from the exhaust area on cold start that quietens when warm, soot tracing around the exhaust manifold, or a hissing noise and unstable idle if the intake side leaks. Drivers may notice down on power, higher fuel use, or for diesels, a change in smoke and turbo spool behaviour. A quick test with soapy water (exhaust) or a gentle carb-cleaner mist (intake) at idle can help pinpoint leaks—use care around hot parts.

Should sealant be used with a new Pajero manifold-gasket?
Generally no. The OEM gasket is designed to seal dry when torqued to spec. The workshop manual specifies where, if anywhere, a small dab of high-temp sealant is appropriate—usually at specific joints or half-moon corners, not across the whole face. Excess sealant can squeeze out and cause issues, so sticking to the factory guidance is the safe bet.

Is it okay to drive with a leaking manifold-gasket?
It’s not ideal. An exhaust leak can erode studs, overheat nearby wiring, and skew oxygen sensor readings on petrol engines. An intake leak can make the engine run lean or cause rough idle, which isn’t great for valves or the turbo on a diesel. Short trips to a workshop are usually fine, but letting it go can turn a cheap gasket job into broken-stud drama.