Radiator Hose O-Ring, Upper or Lower - E46 323i/325i/328i/330i

Coolant hoses are sealed with a rubber o-ring inside the connector. Any time the hose is removed or disconnected the o-ring should be replaced. The o-ring can shrink with heat and time or become damaged. It's common to have leaks when re-using the hose and o-ring.

Instead of replacing the entire hose we offer the correct size replacement o-rings for both the upper and lower radiator hoses on E46 323i, 325i, 328i, and 330i. These o-rings fit with BMW radiator hose part numbers 17127510952 and 11531436408.

Upper Note: the upper hose has another small connection to the expansion tank. See Related Items below.

Lower Note: the lower hose has a temp sensor that also has an o-ring. This does not need to be replaced unless you remove the sensor (or it's leaking already).

These are made of Buna-N (Nitrile) rubber and are compatible with coolant, water, grease, hydraulic oil, and engine oil (not brake fluid). They are rated for temperatures of -40°F to 250°F.

These are sold per o-ring. Each hose uses two.