Parts for your 1990 Mitsubishi Pajero-Exhaust gasket

1990 Mitsubishi Pajero Exhaust Gasket — What It Does and When to Replace It

Based on the Mitsubishi Pajero/Montero Factory Service Manual (circa 1989–1991, Group 15: Exhaust System), the Mitsubishi CAPS/ASA parts catalogue, and common aftermarket application guides (e.g., ACL/Fel‑Pro and the Haynes Pajero/Montero manual), the 1990 Mitsubishi Pajero does use exhaust gaskets. These include the exhaust manifold-to-cylinder head gasket, flange/donut gaskets at pipe joints, and—on 4D56 turbo‑diesel models—gaskets at the turbocharger flanges. So, yes, an exhaust gasket is relevant and fitted to the 1990 Pajero across its typical engines (4G54 2.6 petrol, 6G72 3.0 V6 petrol, and 4D56 2.5 turbo‑diesel).

On a 1990 Mitsubishi Pajero, the exhaust gasket’s job is to keep the hot exhaust gases sealed within the system from the moment they leave the head. The manifold gasket prevents leaks at the head, protecting performance, reducing noise, and keeping fumes out of the cabin. Downstream, flange and donut gaskets seal the joints between pipes, the catalytic converter (where fitted), and the muffler. Turbo‑diesel models also rely on gaskets at the manifold-to-turbo and turbo-to-downpipe connections to maintain boost response and keep everything tidy under the bonnet.

Replacement is pretty straightforward but benefits from a careful, by‑the‑book approach. Any time the manifold comes off—or a joint is split—fresh gaskets should go in. With the engine stone cold, remove the old gasket, clean both mating faces until they’re smooth and free of carbon, then fit the correct new gasket dry (no RTV or general sealants unless the factory manual specifically allows it). Refit fasteners using the factory torque spec and pattern, usually tightening from the centre out. It’s smart to replace tired studs, springs and nuts while you’re there, and use a tiny dab of high‑temp anti‑seize on studs only if the service manual permits.

There’s no fixed service interval for exhaust gaskets, but regular inspections pay off—especially on vehicles that see corrugations, towing, or coastal conditions in Australia and New Zealand. After major exhaust work, a quick re‑check of manifold nut torque once it’s heat‑cycled can help prevent weeping. On 4D56 turbos, keep an eye on the turbo flange joints, slight leaks here can dull spool‑up and add soot under the heat shields.

• Tell‑tales of a leaking Pajero exhaust gasket: a sharp “tick‑tick” on cold start that softens warm, fumes or soot marks around joints, a whiff of exhaust in the cabin, higher fuel use, and for EFI models, potential oxygen‑sensor complaints.
• Driving with a leak isn’t ideal—it can draw cold air back toward hot valves, stress the turbo on diesels, and can trip up a WoF/RWC.

Look after the gaskets and the old Paj will stay quiet, clean and punchy, whether it’s tackling a weekend track or the weekday commute.

FAQs

Does a 1990 Mitsubishi Pajero use an exhaust gasket?
Yes. Factory literature and parts catalogues show a manifold-to-head gasket, flange/donut gaskets at pipe joins, and turbo flange gaskets on 4D56 diesel models. They’re essential for sealing, noise control and safe emissions routing.

What are the common symptoms of a leaking exhaust gasket on a 1990 Pajero?
Expect a ticking sound on cold start that eases as it warms, visible soot around the manifold or flanges, a faint exhaust smell under the bonnet or in the cabin, and slightly lazier performance. EFI versions may also show odd oxygen‑sensor behaviour.

Should sealant be used when fitting a Pajero exhaust gasket?
No general RTV or goop on manifold or donut gaskets. Fit the correct gasket to clean, flat faces and tighten to factory spec in sequence. Only use high‑temp anti‑seize on studs or specified sealants if the service manual explicitly calls for them.