Pelican Technical Article: MINI Cooper (2024)

Both the Cooper and Cooper S use what is known as a poly-ribbed belt (having many channels or ribs on the underside of the belt). The poly-ribbed belt setup utilizes a spring-loaded belt tensioner pulley that provides the proper tension for the belt at all times, making adjustment unnecessary.

When inspecting your belt, the one thing that you want to look for is cracks. If you see any cracks at all, you should replace your belt immediately. The cracks will usually occur on the inside of the belt (the surface that typically rides on the surface of the pulley). With the poly-ribbed belt, replacement is relatively simple. The tension that holds the belt tight can be released using a specialized tool. The tensioners rotate different directions on both the Cooper and the Cooper S, so you will have to rotate the tensioner clockwise or counter-clockwise depending upon your particular car. The description of this process is one of those things that is difficult to describe, but very easy to perform. First, you must remove the fuel tank vent valve which is located above the tensioner on both the Cooper and Cooper S. (See Figure 2) Squeeze the tabs on both the top and bottom to remove the connections. (See Figure 3 and Figure 4 ) Underneath the valve you will also see an electrical plug that must be disconnected. Pull the tab on the side of the plug and pull it off. (See Figure 5) Lastly, push the tab to the side of the valve and remove it from the engine. (See Figure 6)

After the valve has been removed, remove the inner fender liner on the passenger side of the car. This is held in place with a series of plastic tabs called expanding rivets. These have a Phillips head screw in the center that drives the pins of the lower base part outward when tightened. These “fingers” hold the rivet in place. You may need to counterhold the lower base piece while you loosen and remove the plastic Phillips head screws in the center. Once all of these rivets are removed, you can remove the inner fender liner. (see Figure 8)

The removable liners are a neat bit of engineering on the part of MINI. Once they are removed, you gain a lot more access to the various engine and suspension components on the car. With them removed you can see the various components tucked away under the fenders. In my opinion, it is yet another cool example of how BMW tried to remain true to Sir Alec Issigonis’ concept of space-saving in the original Mini.

With the fender liners removed, you can see the serpentine belt routing much more clearly. The tensioner is accessed from above the main frame rail. Place the serpentine belt tool over the tensioner and rotate clockwise (Cooper) or counter-clockwise (Cooper S) - will become immediately apparent how the tensioner releases the belt. You will see that on both models, there are two small holes on the tensioner arm that become visible once the arm is collapsed. Use the tool to release the tension on the belt from the tensioner. (See Figure 9) Once the second hole protrudes from the tensioner, stick the retaining pin through it. (see Figure 10)

Once the tensioner is pinned, the belt will be loose enough to allow removal from off the various pulleys. (see Figure 14)It’s a good idea to take note of the routing of the belt before removal. This will aid in making sure you route the new one correctly. Another tip - if the belt is worn, simply release the tension on it, and snip it with some large tin cutters to pull it out of the car.

The procedure for changing the serpentine belt on the non-supercharged Cooper models is virtually the same, except that the tensioner is different. In this picture, you can see the special tool used for the Cooper to retract the tensioner as well as the lock pin. To retract the belt tensioner on the Cooper, place the forks of the belt tool over the ear of the tensioner and press the tensioner back until you can insert the locking pin into the hole on the side of the tensioner. Once in place, you can let the tension off the belt tool and the tensioner is locked. You can now remove the belt.

Installation of the new belt is easy. Simply slide the new belt onto the pulleys and release the tension on the tensioner. Check to make sure that the belt is securely seated in all of the pulleys. Verify that the ribbed portion of the belt is set against the crankshaft pulley.

Replace the fender liner and re-install the rivets that you removed from the outside of the liner and also the fuel tank vent valve Now, start the car and peek in at the beltsto see that the belt is turning smoothly on all of the pulleys.

The procedure for changing the belt on the R55/R56/R57 MINIs is different than the R50/R52/R53 cars. You’ll need to first remove the left front headlight. Loosen and remove the four 10mm bolts holding it in place. Once free, squeeze the connector on the back of the headlight to unplug it from the car (See Figure 16).

In order to access the serpentine belt tensioner, we will need to remove the upper support panel which MINI refers to as a “lock carrier”. From the left side of the carrier, remove the two 13mm bolts at the end of the panel, then remove the 10mm bolt next to the headlight. Next, remove the two Torx bolts holding the left hood catch to the panel. Finally, remove the two plastic pins securing the front grille to the panel. (See Figure 17)

Now move to the right side of the lock carrier. Remove the two 13mm bolts at the end of the panel. Remove the 10mm bolt next to the headlight and the two Torx bolts holding the left hood catch to the panel. Now remove the two plastic pins securing the front grille to the panel and lift the grille off. Also remove the four 10mm bolts holding the right headlight in place and squeeze the black plastic connector on the back to disconnect it from the car (See Figure 18). You’ll also want to locate the small black plastic lock pin holding the washer fluid reservoir to the lock carrier. Pull the center part of the pin out to release the reservoir (See Figure 19).

The last step to remove the lock bridge is to disconnect the hood release cable. Pry open the end of the black plastic connector. Inside, you’ll see the cable assembly. Pull the end of the cable out of the housing and remove the metal ball from the connector. Once free, pry the plastic connector piece up and out of the lock bridge. Carefully feed it through the hole while you remove the lock carrier (See Figure 20).

Now jack the front of the car up and secure it on jackstands. Remove the right front tire and begin to remove the wheel housing liner. This is held in place by plastic Phillips screws, one Phillips dzus-type screw, one 10mm plastic nut, and two Torx screws. Once all the fasteners have been removed, carefully remove the liner from inside the wheel well (See Figure 21).

From inside the engine compartment, use a 30mm wrench to turn the belt tensioner assembly clockwise. Once fully turned, press the small pin (green arrow) in. This will lock the belt tensioner and slacken the belt (See Figure 22). You may find this a little difficult as there is little space to work with inside.

From inside the wheel well, locate the small plastic pull tab located on the water pump friction wheel. NOTE: It will be difficult to see this as it’s tucked up inside between the chassis and engine. Pull the tab out as far as it will go. This will release the tension on the belt which rides in between the friction wheel and the crankshaft pulley. Now snake the old belt out from inside the engine bay. Take the new belt and fit it over all the pulleys, re-secure the pull tab up inside the friction wheel and rotate the belt tensioner clockwise again. As you do, it will release the locking pin. Now just re-install the wheel, wheel liner, lock carrier and headlights (See Figure 23).

Once the headlights have been re-installed, you will need to re-adjust them. If you have Xenon lights, you’ll first need to make sure that the car has a full tank of fuel, then have someone weighing around 165lbs sit in the driver’s seat. Now turn the lights on and wait 80 seconds for the headlight self-leveling system to stabilize.

Now find the two adjuster screws behind the headlight on either side. The inboard screw adjusts the vertical plane while the outboard screw adjusts the horizontal plane. You’ll want to adjust both screws until both lights are adjusted correctly.