The engine compartment of the Mini Cooper is somewhat cramped, but you can still perform a lot of tasks yourself and save yourself a little money on repairs and maintenance. One of the jobs you can perform yourself is changing the serpentine belt. You can tell the belt needs to be changed if it is cracked or fraying on the side, or if it begins to slip. A slipping belt makes a loud squeaking noise when the engine is running.
Raise the car with the jack and lower it onto the jack stands.
Open the trunk and disconnect both the positive and negative terminals from the battery.
Use the small screwdriver to release the tabs holding the engine control unit (ECU) in place and remove the 10mm bolts holding the airbox and intake in place. If you have an aftermarket intake, you may also need to detach the snorkel from the intake, using a small screwdriver to loosen the clamp. The airbox, intake and ECU are connected, so remove them together.
Remove the skid plate from underneath the car. The skid plate is held in place by two Phillips screws -- one on each side -- and three 10mm bolts along the front.
Remove the 16mm bolt in the lower motor mount.
Align the jack with the bottom of the power steering fan. Put the block of wood on top of the jack and gradually raise the jack until the block of wood is firmly against the bottom of the engine.
Remove the 16mm bolt from the driver's side motor mount. This mount is on top of the engine, so reach in through the hood.
Remove the 10mm bolt holding the wiring harness and the radiator hose to the intake manifold.
Remove the 13mm bolt in the passenger-side engine mount.
Remove the vibration damper bracket. Pop out the three hoses from their quick-release catches and undo the two 16mm bolts. Note that the front bolt is longer than the rear bolt.
Remove the passenger-side motor mount nut using the 18mm wrench.
Raise the engine carefully, using the jack to lift it. Be very careful not to trap or overextend any hoses or wires.
Slide the belt tensioner tool into its holes and use it to release tension on the belt. Slide the belt off the tensioner pulley and work it out of the engine.
Install the new belt over all the pulleys. Release the pressure on the tensioner pulley with the tensioner tool and slide the belt over the tensioner pulley. Add pressure to the belt slowly and gradually to make sure everything is in the proper place.
Lower the engine back into position by lowering the jack. Again, take care not to trap any wires or hoses.
Replace the passenger-side motor mount nut.
Reinstall the vibration damper bracket and clip the hoses back into their quick-release clips. When installing the bracket, the longer bolt goes toward the rear of the car.
Reinstall the 13mm engine mount bolt.
Reinstall the 10mm bolt to secure the wiring loom and the radiator hose to the intake manifold.
Reinstall the lower 16mm motor mount bolt,and then replace the skid plate using the three 10mm bolts along the front and the two Phillips screws on the side.
Reinstall the airbox, intake and ECU assembly.
Lower the car from the jack stands and turn the ignition on for 10 seconds to allow the car to reinitialize.
Reconnect the terminals to the battery in the trunk.
Turn the car on and listen for slippage in the belt and watch the belt carefully to check the belt alignment.
