Goldenwrench Blackline Performance BMW M Car Series Coolant Expansion Tank Cap Cover

The Goldenwrench Blackline Performance BMW M Car Series Coolant Expansion Tank Cap Cover is a precision-machined billet aluminum upgrade for the factory coolant expansion tank cap on compatible BMW M vehicles. Building on the success of the Blackline Billet Oil Cap Cover, this piece applies the same CNC-machined T6 aluminum construction and anodized finish standards to the coolant expansion tank — delivering an OEM+ result with tangible material and aesthetic improvement over the factory plastic component.

Each cap cover is CNC-machined from high-grade T6 aluminum and available in multiple anodized finishes, including the race-inspired Edition Red. All logos and design details are created using an advanced 3D milling process, machined directly into the cap surface for a permanent, high-definition finish. The Blackline Performance design language carries over from the oil cap cover for a cohesive engine bay appearance. Compatible with N55, S55, and S65 engine-equipped BMW M models that use the large coolant expansion tank configuration. Verify that your factory coolant cap shape matches the product images before purchasing.

This is a cap cover, not a full replacement. It installs directly over the factory coolant cap in minutes with no modification required. Each kit includes the billet coolant expansion tank cap cover and an installation guide.

Product Details

• Precision CNC-machined billet T6 aluminum construction
• Available anodized finishes: Edition Red, Anthracite Grey, Motorsport Blue
• 3D-milled logos machined into cap surface for a permanent, premium finish
• Designed for BMW M models with N55, S55, and S65 engines
• Installs over factory coolant cap — no modification required
• Includes billet coolant expansion tank cap cover and installation guide

Vehicle Applications

• BMW E90 M3 (S65 Engine)
• BMW E92 / E93 M3 LCI (S65 Engine)
• BMW F87 M2 (N55 Engine)
• BMW F87 M2 Competition / M2 CS (S55 Engine)
• BMW F80 M3 (S55 Engine)
• BMW F82 / F83 M4 (S55 Engine)

Notes

• This is a cover that affixes to the top of the factory coolant cap — not a full cap replacement
• Verify that your factory coolant cap shape matches the product images before purchasing
• Designed for BMW M models fitted with the large coolant expansion tank