Coolant Expansion Tank Cap

Product Details

Don't let a weak factory plastic cap compromise your BMW's cooling system when pushing it to the limit. Whether you are daily driving your ultimate driving machine or turning laps at the track, keeping your coolant under steady pressure is critical to preventing thermal spikes and engine damage. This Febi Bilstein coolant expansion tank cap is designed to maintain the exact 1.4 bar pressure required to maximize your coolant's boiling point. Over time, the internal relief valve in your original cap will weaken and vent too early; swap it out with this high-quality Febi replacement to guarantee your system holds pressure when you need it most. It's cheap insurance against track-day disasters.

Key Features

• Engineered to hold a precise 1.4 bar opening pressure for optimal boiling point protection

• Built with a heavy-duty spring-loaded relief valve to vent excess pressure safely

• Supplied with a fresh, pre-installed gasket seal to stop slow pressure leaks in their tracks

• Rugged polymer construction designed to withstand severe heat cycles and cooling system pressures

• Exact-fit design for quick, hassle-free replacement on a wide range of modern BMW chassis

Specifications

• Brand: Febi Bilstein

• Part Number: 46221

• Replaces OE Numbers: 17117639020, 17117521071

• Opening Pressure: 1.4 bar (approx. 20.3 psi)

• Material: High-strength plastic

• Thread Size: M52 x 3 mm

• Color: Black

• Package Includes: Cap with pre-installed rubber seal/gasket

Prop 65 Warning

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Lifetime Replacement

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