MMX Washer Fluid Filler Cap for G8x BMW
Give your engine bay a clean, premium look with this MMX billet washer fluid cap. It is a full replacement for the factory plastic cap, not a stick-on cover. UK engineered and machined from solid aluminium, then gloss-anodised in black for a durable finish.
Why this cap matters
- Full replacement design for a neat, OE-style fit
- Integrated seal for a secure, leak-free closure
- Billet aluminium construction for strength and long life
- Gloss black anodising resists marks and corrosion
- Refined feel every time you top up the washer bottle
Each cap is CNC machined on 5-axis equipment for precise shape and fit, then hand polished before anodising. The result is a tidy, consistent finish that lifts the overall look under the bonnet without being flashy.
Fitment
Designed for BMW G8x M3 and M4 models, including saloon, touring, coupe and convertible. This cap replaces the original washer bottle cap on these platforms.
Please use our vehicle lookup tool to confirm fitment for your car, or check the Vehicle Fitment tab for full details.
Installation
Direct replacement. Pop off the factory cap and press the MMX cap into place on the washer bottle neck. No permanent changes needed and no special tools in most cases.
Ensure the cap seats fully on the bottle neck and the seal is clean before use. Wipe away any fluid on the neck to avoid drips.
| SKU | MMR03-0002 |
| Brand | MMX |
| Product type | Washer fluid filler cap – full replacement |
| Material | Billet aluminium |
| Finish | Hand polished, gloss black anodised |
| Manufacture | CNC machined, 5-axis |
| Fitment group | BMW G8x M3/M4 platforms |
Pair it with other MMX under-bonnet dress-up parts for a consistent factory-plus look.






