Thermostat & Water Pump Replacement DIY

[Bimmer360]

Thermostat & Water Pump DIY
by Ernest aka Bimmer360

Disclaimer:
Bimmer360 is not responsible or liable for any damage of any property or injury resulted in performing this DIY. It is highly recommended to implement safety procedures at all times.

Vehicle Info:
2001 BMW X5 4.4i V8

Tools/Materials Needed:
- Various sizes of sockets
- BMW Special Tool (optional)
- Prying Tool
- Flathead Screwdriver
- Set of different size sockets
- 27mm hex socket
- 1 5/16 Wrench
- Torque Bit #45
- Allen range
- 3 Gallons of BMW Coolant
- 3 Gallons of Distilled Water

Step 1: Raise your car and put jack stands on each side and make sure they are supported safely. Remove the splash shield from under engine by removing the nuts all around exposing the bottom part of the radiator. Put shield in a safe place far enough so you won’t step on it while working on your car. Also, remove the cover underneath by removing the 14 bolts around.

On the bottom part of the radiator (right side if you are facing the car), allow coolant to drain by using oil pan or alike.

Step 2: Next step is to remove the Air Intake hood by using a prying tool to remove the expansion rivets and release duct at the air box exposing top of the fan shroud. On top of radiator, there are 3 rivets, gently pry them since the metal part is kinda soft and can easily be bent out of shape. Also, remove the engine cover using allen wrench and loosen 4 of the hex bolts.

Step 3: Using a flathead screw driver, look down and place it between the 2 metal bolts on the pulley at an angle where the tip of the screwdriver will rest under the second nut and the rest on top of the first one. While doing that, use 1 1/16 wrench on fan clutch nut and turn in a clockwise direction while counter holding the pulley with the screwdriver. Spin fan off of the thermostat and remove the pulley as well by unscrewing the 4 bolts that secures it.

Note: Fan’s clutch nut to thermostat, the torque spec is 30Nm (22 ft-lb).

Step 4: Using a #45 torque bit, counter clockwise the stainless metal like pulley and release the belts

Step 5: Unclip the Air Quality Sensor and the Auxiliary Fan Connector from the fan shroud and lift it with the fan together out of the engine compartment. Again, place them in a safe place.

Step 6: Detach electrical connector from AUC sensor. Place harness aside. Then press on the fasteners both sides of the cooling fan cowl and push towards engine and raise fan cowl slightly and work lower retaining tabs out from the base radiator.

Step 7: Disconnect MAF sensor electrical harness connector and remove it along with all the ducts.

Step 8: Remove radiator (see Bentley manual or any other resource on removing this).

Step 9: Disconnect electrical harness and connector and sensor from thermostat housing and remove all hoses by using a flathead screwdriver and loosen the clips on each hoses. There are 3 hoses attached, total.

Note: When removing the smaller bottom hose on the left hand side, prepare a pan and place it underneath to catch a lot of coolant that will pour out of the thermostat.

Step 10: Remove Vibration Damper. This has 8 bolts around and 1 huge crankshaft hub bolt in the center where that requires special tool (11 2 450). This tool needs to be installed on the damper utilizing the holes where the bolts where removed by using the same bolts. Then an assistant (if available) needs to grip and counter hold it while you are turning the center hub bolt clockwise using a 27mm socket. If an assistant is not available, rest handle of tool on front subframe (be careful when doing this or hire a professional to just remove this part and pay him like $20 or something). A friend of mine was able to remove the thermostat without removing the damper, go figure!

Then pull of hub and remove the vibration damper. When reinstalling the damper and bolt, you might want to use discretion when tightening it. Bentley mentions 4 stages when tightening the bolt:

Hub to Crankshaft:
Stage 1 - 100Nm (74 ft-lb)
Stage 2 - 60 degrees torque angle
Stage 3 - 60 degrees torque angle
Stage 4 - 30 degrees torque angle

Vibration Damper:
22 Nm (16 ft-lb)

Step 11: With the damper out of the way, remove thermostat’s mounting fasteners, total of 6 bolts. All the bolts are M6 in size but bolts A are 105mm in length while bolts B are 35mm only.

Step 12: Once all bolts are removed, slide the thermostat away from the coolant pipes. Be gentle and extra careful not to dislodge pipe settings from fittings at rear of engine.

Torque specs:
1.) Thermostat to timing chain cover – 10Nm (89 in-lb)
2.) Pulley to Thermostat – 10Nm (89 in-lb)
3.) Block drain plug to engine block:
M14 x 1.5 – 25 Nm (18 ft-lb)
M16 x 1.5 – 35 Nm (26 ft-lb)
M18 x 1.5 – 40 Nm (30 ft-lb)
4.) Radiator drain plug – 2.5 Nm (22 in-lb)
5.) Thermostat cover to Water Pump Assembly – 10 Nm (89-in-lb)

Step 13: Mount Water Pump to thermostat using the same bolt or if you ordered new ones. Installation in reverse order for the rest of the parts.

Step 14: Top off expansion tank with a 50/50 mixture of BMW Coolant and distilled water. Follow bleeding procedure since 4.4i and 3.0 are different. Check for leaks and make sure there is none.

Step 15: Open a cold drink of your choice to reward yourself as you watch the X performs and not leak fluid! In my case, instead of a cold drink, I had this special delicacy from Asia called “Kutsinta” (Rice Cake made from the finest rice and brown sugar) yummy….Dang, that taste good!