It is recommended to replace the two 10MM hex screws.

OE Part No. 07119905591

Detach the old factory hose from your vehicle's cylinder head.

It's extremely important to check the hose port on the cylinder head for any debris. The old hose almost always breaks off small plastic pieces that could possibly fall into the engine. Trace your finger in a circular motion and check there are no plastic pieces broken off.

Disconnect the expansion tank return hose by prying up on the metal retention clip and simply pulling it off of the nipple.

Remove the two 10MM expansion tank retention screws.

Move the expansion tank all the way forward, to give yourself access to the vehicle's thermostat.

Loosen the band clamp holding the hose to the thermostat (white arrow) with a flathead screwdriver. Once loosened, pull the hose from the thermostat.

Carefully wiggle the old hose out from your engine bay.

Transfer the band clamp from the old hose to the new one. Install the band clamp so the screw faces upward, so you can easily reinstall it and remove it in the future.

(Hose Part No. 11437545890)

Install the hose to the thermostat and tighten the band clamp screw until it's snug into place and can not be pulled off.

Firmly attach the new hose to your vehicle's cylinder head and hand tighten the retention screws into place.

Tighten the cylinder-head hose retention screws into place with a 10MM wrench and/or socket.

Place the expansion tank back into place ensuring the drain port at the bottom fully aligned to the frame of the vehicle.

Install and hand-torque the expansion tank screws with a 10MM socket and ratchet.

Re-install expansion tank return hose to the expansion tank nipple and press retention clip down into place.

Fill your cooling system with approved BMW coolant until full, then carry out cooling system bleed procedure.

Good job replacing your thermostat to cylinder head hose! Be sure to keep an eye out for coolant leaks or any signs of overheating.