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.
- Park the BMW and allow the engine to cool down. Set the parking brakes.
- Pull the hood release under the dashboard on the driver’s side of the vehicle.
- Open the hood and locate the coolant fitting near the front of the engine.
- Remove two 10mm bolts.
- Remove the old fitting from the engine block.
The o-ring needs to be removed as well, as it may get stuck inside. - Clean the outlet on the engine block. Remove any remaining pieces from the coolant hose.
- Install the new fitting. Lubricate the seal O ring before installation. Tighten the two 10 mm bolts.
- Slide the coolant hose on the outlet port.
- Tighten the clamp.
- Add engine coolant. It is recommended only to use the BMW engine coolant.
The o-ring needs to be removed as well, as it may get stuck inside.
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 it is not necessary to replace the coolant hose.
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.
I need the 2 bolts. Lost mine between time I took the part out and the new one came in. Any help? I tried looking online and found nothing.
Where can you purchase the medal connector from? No auto stores I’ve been to don’t seem to have it ..
Did anyone had white vapor come from the radiator at first.?
Cuz the coolant was sprayed there?
Where can I buy this fitting and hose assembly because for my 328i this area was the source of the leak. I opened this hose and the fitting was damaged. So it needs to be replaced.
Thanks
No you don’t have to– I just did mine during my lunch break. the hose will have coolant so I put a paper coffee cup underneath and emptied enough out of the hose to put it in place again. top up coolant and bleed w/ water pump procedure after.
Do you have to drain your coolant before changing this fitting
On what part of the coolant outlet? Is this the original manufactures’ outlet? If so, most original ones are made with a composite plastic resin with two small metal eyelets where the 10mm bolts go to mount the fitting, so it tends to brake down into an almost wood like substance when exposed to extremely high temps over time. In this situation I don’t believe the engine or transmission would be a major concern if a piece broke off, other than the possibility of a coolant leak and overheating. But if your fitting does happen to be metal then I would say an immediate flush of the system would need to be performed. Hope this offers any useful information to you. Best of luck and Happy Trails!
#LoveTheLove
The metal piece of mine is semi broken. I am concerned if that piece may have fallen down through the tube into who knows what? Any advice ?