Parts for your 2004 Daihatsu Yrv-Oil cap

2004 Daihatsu YRV Oil Cap — What it does and how to look after it

Referencing technical sources, the oil filler cap is absolutely relevant and fitted to the 2004 Daihatsu YRV. The 2004 YRV Owner’s Manual engine bay diagram identifies the oil filler cap on the cam/rocker cover of the K3‑VE engine, the Daihatsu K3‑VE Engine Repair Manual (Lubrication section) depicts the cap and its sealing gasket on the cylinder head cover, and the Daihatsu Electronic Parts Catalogue for chassis codes M201G/M211G lists a “Cap, Oil Filler” with an integral rubber seal. That’s the cap you twist off to add oil under the bonnet.

On this YRV, the oil cap does a deceptively important job. Beyond being the obvious point for topping up, it seals the top of the engine so the crankcase ventilation system can do its thing properly. A healthy cap keeps dust, moisture, and road grime out, and prevents warm oil mist from weeping or splashing onto the engine. Leave it loose or cracked and you can wind up with oil smells, a messy rocker cover, and even a slightly rough idle from unmetered air sneaking in.

As part of regular servicing, it’s worth giving the cap a quick once‑over at every oil change. Check that the rubber seal isn’t flattened, brittle, or split, and that the cap threads aren’t chewed out. If the seal’s past it, replace the seal or the whole cap — it’s a small, inexpensive part that protects a very expensive engine. Refit the cap by hand until it seats, then give it a firm nip