Fix BMW Broken Coolant Hose

BMW engine radiator hose outlet to the engine block may break or crack while the engine is running, causing coolant loss and the engine to overheat.

The original outlet is made of plastic and is prone to failure. The part is found on many BMW models, including the popular BMW 335i.

What you will need

• BMW Water Hose Fitting 11537541992
  • Interchangeable parts 11537544638
  • Fit the N54, N53, N52, and N51 3.0-liter motors
• OEM BMW Engine Coolant
• Flathead Screwdriver
• 10mm Socket
• Ratchet Wrench

The other advantage of the aluminum design over the OEM part is that the aluminum fitting has a larger diameter, which improves the coolant flow.

Procedure

The fitting is mounted with two bolts and has a 1-inch diameter.

The hose connects the coolant thermostat housing hose at the front of the engine.

1. Park the BMW and allow the engine to cool down. Set the parking brakes.
2. Pull the hood release under the driver’s dashboard.
3. Open the hood and locate the coolant fitting near the front of the engine.
4. Remove two 10mm bolts.
5. Remove the old fitting from the engine block. The o-ring must also be removed, as it may get stuck inside.
6. Clean the outlet on the engine block. Remove any remaining pieces from the coolant hose.
7. Install the new fitting. Lubricate the seal O ring before installation. Tighten the two 10 mm bolts.
8. Slide the coolant hose on the outlet port.
9. Tighten the clamp.
10. Add engine coolant. It is recommended only to use the BMW engine coolant. 

Notes

The best solution is to replace the plastic fitting with a metal part that will not leak and crack like the original. See what you will need to list above.

The broken part may come as one piece with the hose when purchased from the dealer. We could not verify if BMW sells only the outlet fitting. This problem can be fixed by replacing the defective outlet, and replacing the coolant hose is unnecessary. The hose should be replaced if it is leaking or damaged.

Applications

This part is found on N54, N53, N52, and N51 3.0-liter motors.

This guide applies to the following vehicles:

• N54 3.0L twin-turbo motors in 335i, 335xi, 135i
• N53 (3.0-liter non-turbo) in 2006 – 2010 325i, 330i, 525i, 525xi, 528i, 528xi, 530i, 530xi
• N20 (2.0-liter turbo) Z4 2013 and newer
• N52 X3
• N55 motors

We hope you find the “Fix BMW Broken Coolant Hose” guide helpful. Check these troubleshooting and repair guides for more help on your BMW.