Parts for your 2013 Toyota Mark x-Oil cap

2013 Toyota Mark X Oil Cap — Purpose, Care, and When to Replace

The 2013 Toyota Mark X absolutely uses an engine oil filler cap, it’s a standard, essential part on both GRX130-series engines (4GR-FSE 2.5L and 2GR-FSE 3.5L). This is confirmed by Toyota technical material: the 2013 Mark X Owner’s Manual (Do-it-yourself maintenance – Engine oil) shows the screw-on oil filler cap under the bonnet, the Toyota Electronic Parts Catalogue lists a “Cap Sub-Assy, Oil Filler” for GRX130/GRX133, and Toyota’s repair manual for the GR-series lubrication system depicts the cap as part of the rocker cover assembly. So yes—an oil cap is fitted and it matters.

On the Mark X, the oil cap does more than just give you a spot to add oil. It seals the top of the engine to keep dust and moisture out, helps prevent oil mist from escaping, and supports proper crankcase ventilation via the PCV system. If the cap’s loose, missing, or its rubber seal has gone hard, expect oil weep, a hot oil smell, possible engine bay mess, and even a rough idle or warning light from unmetered air sneaking into the system.

During regular servicing, the oil cap deserves a quick once-over. A genuine or high-quality equivalent cap with a fresh rubber packing keeps everything tidy and leak-free. Wipe around the cap before opening so grit doesn’t fall in, then reinstall it hand-tight only—no tools needed. On the Mark X V6, it sits on the cam cover (typically the right-hand bank when facing the car), and should sit flush and seal cleanly every time.

• Inspect each service for cracks, a brittle or flattened seal, and damaged threads.
• Clean the cap’s threads and the sealing surface, replace the rubber packing or the cap if it won’t seal nicely.
• If the cap’s lost or split, don’t drive far—oil can spray out. Fit the correct cap before normal use.
• There’s no set replacement interval, many last years, but age, heat, and handling can shorten their life. If there’s seepage or smell, swap it.

For top-ups, use the oil grade specified for your market and climate (often 0W-20 or 5W-30 for these engines). After refitting the cap, run the engine for a minute and check for any trace of oil around the seal—easy as.

Popular questions

Where is the oil cap on a 2013 Toyota Mark X?
The oil cap is on the top of the engine, typically on the right-hand cylinder bank’s rocker cover when standing in front of the vehicle. It’s clearly labelled and accessible once the plastic engine cover is lifted off or unclipped.

What oil cap fits the 2013 Mark X?
Toyota specifies a “Cap Sub-Assy, Oil Filler” for GRX130/GRX133 models. The correct cap depends on engine and market, so matching by VIN is best. A genuine Toyota cap or a reputable equivalent with the correct rubber packing is recommended.

Can a loose or missing oil cap cause issues?
Yes. It can create a vacuum leak that upsets idle quality, trigger a warning light, and let oil mist escape—leading to smells, residue, or smoke if oil hits hot parts. Fit and tighten the correct cap before driving.