Parts for your 2018 Nissan X-trail-Oil cap

2018 Nissan X‑Trail oil cap — fitted, important and worth keeping in top nick

Technical sources confirm the 2018 Nissan X‑Trail (T32) is fitted with an engine oil filler cap. The Nissan X‑TRAIL (T32) Owner’s Manual (2018, “Engine oil” section) instructs the driver to remove the oil filler cap to add oil. The Nissan Service Manual (Engine Mechanical sections for MR20DD/QR25DE/M9R) depicts the cap on the cam/rocker cover, and Nissan’s Electronic Parts Catalogue (FAST) lists a “Cap Assy – Filler, Engine Oil” for these engines. So, yes — an oil cap is used on the 2018 X‑Trail.

On a 2018 Nissan X‑Trail, the oil cap is a small but vital piece of kit. It seals the top of the filler neck on the rocker cover, keeping dust, water and grit out of the oil, and helping maintain proper crankcase ventilation. Without a healthy cap and seal, contaminants can get in and oil vapour can get out — neither is good for engine longevity. It’s also the obvious access point when topping up oil between services.

As part of regular servicing of a 2018‑nissan‑x‑trail oil-cap, it pays to give the cap a quick once‑over. Before removing it, wipe around the area so no muck drops inside. Twist the cap anti‑clockwise to remove, top up as needed, then refit and hand‑tighten clockwise until it seats firmly. No spanners — it’s designed to be snug by hand, not cranked tight.

What to look for? Check the cap body for cracks, heat damage or a wobbly centre insert, and inspect the rubber O‑ring for flattening, hardening or splits. A perished seal can lead to light oil misting around the cover, a whiff of hot oil under the bonnet, or even a slightly rough idle from a minor air leak on some engines. If any of that shows up, a replacement cap (or new seal, where applicable) is cheap insurance.

There’s no set replacement interval for the oil cap — it’s a replace‑when‑needed item. If the cap has damaged threads, a broken tether/tab, or the seal’s past its best, swap it out. Keeping a genuine‑spec cap matched to the MR20DD, QR25DE or M9R engine ensures proper fit and venting. It’s a quick, low‑cost job that protects far pricier engine components and keeps the X‑Trail running sweet as.

• Wipe the area clean before opening.
• Hand‑tighten only, don’t overdo it.
• Replace the cap/seal if cracked, loose or leaking.

FAQs

Where is the oil cap on a 2018 Nissan X‑Trail?
It sits on the top of the engine’s rocker/cam cover, usually marked “OIL” or with the recommended grade symbol. Stand at the front with the bonnet up and look for a round, twist‑off cap near the centre or one side of the cover. Turn anti‑clockwise to remove, and refit by hand until snug.

Which oil cap fits the 2018 X‑Trail?
Use a cap specified for the T32 X‑Trail’s engine (MR20DD 2.0 petrol, QR25DE 2.5 petrol or M9R 2.0 diesel). Genuine Nissan caps are listed in the FAST parts catalogue as “Cap Assy – Filler, Engine Oil” for these engines, and quality aftermarket equivalents are available. Matching by VIN or engine code ensures the correct seal and thread.

What happens if the oil cap is left off or loose?
Expect oil mist or splatter under the bonnet, an oily smell, and potential intake/ventilation issues that can cause a rough idle. If it’s missing or loose, switch off as soon as it’s safe, clean any spilled oil, and refit or replace the cap before driving further.