Parts for your 2018 Mitsubishi Asx-Exhaust gasket

2018 Mitsubishi ASX exhaust gasket: what it does and when to replace it

Yes, the 2018 Mitsubishi ASX uses exhaust gaskets. Mitsubishi’s own technical literature confirms it: the Mitsubishi Motors Service Manual for the GA2W/GA3W platform (ASX/RVR/Outlander Sport) lists gaskets at the manifold-to-cylinder head, and at key exhaust flanges. The Mitsubishi ASA electronic parts catalogue for 2018 ASX variants also shows sealing rings/donut gaskets at the front pipe and flat gaskets at other joints. Whether it’s the common 2.0-litre petrol or market-specific diesel, there are gaskets in the exhaust path to keep things sealed and quiet.

On this ASX, exhaust gaskets are there to seal the high-temp, high-pressure gases where two metal surfaces meet. They stop fumes sneaking out, keep the note civil, protect against underbody heat spikes, and help the oxygen sensors and catalytic converter do their job. You’ll typically find a multi-layer steel (MLS) gasket at the exhaust manifold, and a crush/donut gasket or flat graphite/steel gasket at the front pipe and other flanged joins.

Signs the ASX might want fresh gaskets include:

• A ticking/choofing noise on cold start that softens as it warms
• Exhaust smell near the engine bay or underbody, or black sooty marks at a flange
• Raspy note, slight loss of go, higher fuel use, or engine light from skewed O2 readings

There’s no set replacement interval, they’re changed when disturbed or if they leak. Any time the manifold, front pipe, cat, or DPF (diesel) is removed, fit new gaskets. Reusing old ones often ends in leaks.

Good workshop practice on a 2018 ASX:

• Use quality gaskets that match the joint type (MLS for manifold, correct crush ring for the front pipe)
• Clean mating faces, replace rusty studs/nuts, follow Mitsubishi torque specs and tighten evenly
• After refit, do a warm-up then re-check for weeps, rattles, or soot
• During regular servicing, inspect flanges, clamps, hangers and heat shields, surface rust is normal, but flaking metal or loose joints isn’t

Left to blow, a leaking gasket can let fumes creep towards the cabin, cook nearby components, and confuse the sensors, which can upset fuel trims and the cat. Sorting it early is safer, cheaper, and keeps the ASX feeling right on the road.

Popular questions

Does the 2018 ASX have a separate exhaust manifold gasket and where is it?
Yes. It sits between the cylinder head and the exhaust manifold at the front of the engine (under the heat shield). On petrol models it’s a multi-layer steel gasket, diesel variants use a similar sealing approach. It should be replaced any time that joint is undone, as once compressed it won’t reseal properly.

How much does it cost to replace an exhaust gasket on a 2018 ASX?
It varies with which gasket and local labour rates. A front pipe/donut gasket is usually a short job (around an hour). A manifold gasket is more involved, often a few hours due to shields, studs and access. Parts are typically modest—think tens rather than hundreds—while labour is the bigger slice. In AU/NZ workshops, expect a small job to be relatively affordable and a manifold job to be mid-range.

Is it OK to keep driving with a leaking exhaust gasket?
Short term, it might just sound a bit sharp, but it’s not ideal. Hot gases can damage nearby components, fumes can find their way towards the cabin, and the leak can skew oxygen sensor readings, potentially harming the catalytic converter over time. It can also lead to a failed inspection (e.g., WOF/reg). Best to book it in promptly.