Auxiliary drivebelt check and renewal (Every 10 000 miles or 12 months)

Routine maintenance and servicing / Auxiliary drivebelt check and renewal (Every 10 000 miles or 12 months)

General
1 The auxiliary drivebelt is of the flat, multiribbed (or “polyvee”) type, and is located on the right-hand end of the engine. It drives the alternator, water pump, power steering pump and (when fitted) the air conditioning compressor from the engine’s crankshaft pulley.

2 The good condition and proper tension of the auxiliary drivebelt is critical to the operation of the engine. Because of their composition and the high stresses to which they are subjected, drivebelts stretch and deteriorate as they get older. They must, therefore, be regularly inspected.

Check
3 With the engine switched off, open and support the bonnet, then locate the auxiliary drivebelt on the right-hand end of the engine, under the engine right-hand mounting bracket. (Be very careful, and wear protective gloves to minimise the risk of burning your hands on hot components, if the engine has recently been running.) For improved access, jack up the front right-hand side of the vehicle, support it securely on an axle stand, remove the roadwheel, then remove the auxiliary drivebelt cover (two fasteners) from inside the wheel arch (see illustration).

11.3 Removing the auxiliary drivebelt cover - it is secured by a fastener at each end (arrowed) - from inside the right-hand front wheel arch

4 Using an inspection light or a small electric torch, and rotating the engine when necessary with a spanner applied to the crankshaft pulley bolt, check the whole length of the drivebelt for cracks, separation of the rubber, and torn or worn ribs (see illustration). Also check for fraying and glazing, which gives the drivebelt a shiny appearance. Both sides of the drivebelt should be inspected, which means you will have to twist the drivebelt to check the underside. Use your fingers to feel the drivebelt where you can’t see it. If you are in any doubt as to the condition of the drivebelt, renew it (go to paragraph 7).

11.4 Check the auxiliary drivebelt for signs of wear like these. Very small cracks across the drivebelt ribs are acceptable. If the cracks are deep, or if the drivebelt looks worn or damaged in any other way, renew it

Drivebelt tension
5 The auxiliary drivebelt is tensioned by an automatic tensioner; regular checks are not required, and manual “adjustment” is not possible.

6 If you suspect that the drivebelt is slipping and/or running slack, or that the tensioner is otherwise faulty, it must be renewed. To do this, remove the drivebelt as described below, then unbolt the tensioner (two Torx-type screws accessible from underneath, via the wheel arch) from the alternator mounting bracket (see illustration). On fitting the new tensioner, ensure it is aligned correctly on its mountings, and tighten the screws to the specified torque wrench setting.

11.6 The auxiliary drivebelt is tensioned by an automatic tensioner; Torx screws (arrowed) secure it to alternator mounting bracket

Renewal
7 Open the bonnet. Jack up the front righthand side of the vehicle and support it securely on an axle stand, remove the roadwheel, then remove the auxiliary drivebelt cover (two fasteners) from inside the wheel arch.

8 If the existing drivebelt is to be refitted, mark it, or note the maker’s markings on its flat surface, so that it can be installed the same way round.

9 Reaching up between the body and the engine (above and to the rear of the crankshaft pulley), apply a spanner to the hexagon in the centre of the automatic tensioner’s pulley. Rotate the tensioner pulley clockwise to release its pressure on the drivebelt, then slip the drivebelt off the crankshaft pulley, and release the tensioner again (see illustration). Working from the wheel arch or engine compartment as necessary, and noting its routing, slip the drivebelt off the remaining pulleys and withdraw it.

11.9 Rotate the tensioner pulley clockwise to release its pressure on the drivebelt, then slip the drivebelt off the crankshaft pulley

10 Check all the pulleys, ensuring that their grooves are clean, and removing all traces of oil and grease. Check that the tensioner works properly, with strong spring pressure being felt when its pulley is rotated clockwise, and a smooth return to the limit of its travel when released.

11 If the original drivebelt is being refitted, use the marks or notes made on removal, to ensure that it is installed to run in the same direction as it was previously. To fit the drivebelt, arrange it on the grooved pulleys so that it is centred in their grooves, and not overlapping their raised sides (note that the flat surface of the drivebelt is engaged on the idler, tensioner and water pump pulleys) and routed correctly (see illustrations). Start at the top, and work down to finish at the crankshaft pulley; rotate the tensioner pulley clockwise, slip the drivebelt onto the crankshaft pulley, then release the tensioner again.

11.11A When installing the auxiliary drivebelt, make sure that it is centred - it must not overlap either edge of the grooved pulleys

11.11B Auxiliary drivebelt routing

1 Power steering pump 2 Idler pulley
3 Alternator
4 Automatic tensioner
5 Air conditioning compressor (when fitted) 6 Crankshaft pulley
7 Water pump pulley

12 Using a spanner applied to the crankshaft pulley bolt, rotate the crankshaft through at least two full turns clockwise to settle the drivebelt on the pulleys, then check that the drivebelt is properly installed.

13 Refit the auxiliary drivebelt cover and roadwheel, then lower the vehicle to the ground.