Parts for your 2018 Mitsubishi Eclipse cross-Oil cap

2018 Mitsubishi Eclipse Cross oil cap — what it does and how to look after it

Yes, the 2018 Mitsubishi Eclipse Cross uses an engine oil filler cap. This is confirmed by technical sources such as the Mitsubishi Motors Owner’s Manual for the Eclipse Cross (engine compartment overview and “Checking engine oil” sections), the factory service manual lubrication diagrams, and Mitsubishi parts catalogues for the 1.5L turbo petrol (4B40) and available diesel variants, each listing an oil filler cap on the cam/rocker cover. It’s a standard, required component on these internal-combustion engines.

The oil cap’s job is simple but crucial. It seals the top of the engine where oil is added, keeping dust and moisture out while maintaining proper crankcase sealing and PCV performance. On the Eclipse Cross, the cap sits atop the valve cover under the bonnet, usually marked with the oil can symbol. A sound cap prevents oil mist from weeping out, helps keep the engine bay clean, and ensures the engine breathes as designed.

As part of routine servicing (typically every 12 months or around 15,000 kilometres, or as per the local schedule), it’s smart to give the oil cap a quick once-over. Check the cap body for cracks, heat warping, or a loose fit. Pay close attention to the rubber seal/O-ring — if it’s flattened, brittle, or cracked, it won’t seal properly. A worn cap can lead to oil odours, a light film of oil around the filler neck, and, in some cases, rough running due to upset crankcase ventilation.

Replacement is inexpensive and straightforward. Choose a genuine or high-quality aftermarket cap that matches the Eclipse Cross engine variant, the right cap should seat snugly and hand-tighten smoothly. Avoid “universal” caps that don’t positively lock or seal. If only the seal is perished and a separate gasket is available for your cap, swap it, otherwise, replace the complete cap.

Quick care tips for owners:

• Wipe the filler neck before refitting the cap after an oil top-up to protect the seal.
• Hand-tighten only — firm and snug, not cranked on. No tools required.
• If the cap won’t seat or keeps backing off, replace it immediately.

Driving without the oil cap isn’t advisable. Oil can splash out, attracting dust and creating a mess on belts and hoses. If a cap goes missing, park up and fit a correct replacement as soon as possible.

Technical references: Mitsubishi Motors Eclipse Cross (2018) Owner’s Manual — engine compartment overview and engine oil sections, Mitsubishi workshop/service manual — lubrication system and cylinder head cover illustrations, Mitsubishi ASA/parts listings — engine oil filler cap for 4B40 engine.

Popular questions

Where is the oil cap on a 2018 Mitsubishi Eclipse Cross?
It’s on top of the engine, threaded into the valve (rocker) cover under the bonnet. Look for the oil can symbol. On the 1.5L turbo petrol, it’s easy to spot near the front or top of the cover depending on market layout.

What are the signs the oil cap needs replacing?
Common flags include a persistent oil smell after driving, light oil mist around the filler neck, a cap that won’t sit square or keeps loosening, visible cracks, or a hardened/flattened O-ring. Any of these warrant a new seal or a new cap.

Is it safe to drive with a missing or loose oil cap?
Not recommended. Oil can be flung out, contaminants can get in, and the engine may run poorly due to disrupted crankcase ventilation. If the cap is missing, fit the correct replacement promptly before driving any distance.