Drivebelt - tensioning and renewal

Cooling and heating systems / Drivebelt - tensioning and renewal

1 The drivebelt for the alternator and coolant pump is correctly tensioned if it deflects through 10.0 mm (0.39 in) under moderate thumb pressure at the mid point of the longest run of the belt.

2 To tighten the belt, release the mounting and adjuster nuts on the alternator and prise the alternator away from the engine. Tighten the nuts when the belt is taut and then re-check the tension as previously described.

Never over-tension a belt or the coolant pump or alternator bearings may be damaged.

3 Check the condition of the belt at regular intervals. If frayed or cracked, renew it in the following way.

4 Release the alternator mounting and adjuster nuts and push the alternator fully in towards the engine. Slip the belt off the pulleys. If this is difficult, turn the crankshaft pulley using a spanner on its retaining nut while pressing the belt over the edge of the pulley rim. Use this method to fit the new belt after first having engaged it with the coolant pump and alternator pulley grooves.

5 Tension the belt as previously described.

6 The tension of a new belt should be checked and adjusted after the first few hundred miles of running.