Replacing and tensioning the toothed belt
Checking V-belts
Required special tool:
- At BMW workshops, V-belts are checked on special machines. If special equipment is not available, test "finger".
Required wear parts:
- V-belts of appropriate sizes. It is recommended that all V-belts be replaced at once, even if only one of them is worn. The dimensions of the V-belts are indicated in the instruction manual.
The condition and tension of the V-belts of the generator, the power steering pump, and the air conditioning compressor are checked. Insufficient tension accelerates wear or failure of the V-belt. If the tension is too high, the bearings in the respective units may be destroyed.
V-belt replacement is carried out in case of: severe wear, bead fraying, traces of oil, cracking, transverse breaks.
Check the tension of all V-belts, namely, strongly press the belt with your finger in the middle between the two pulleys located at the greatest distance. In this case, the V-belt must bend from 5 to 10 mm.
To replace the alternator V-belt, see section "Engine".
Power steering pump V-belt: Loosen nut 1 and turn tensioner 2 accordingly. It is also recommended to loosen the two lower bolts on the pump support to make it easier to deflect the pump. After tensioning the belt, tighten bolts 9 again. The V-belt of the air conditioning compressor is also tensioned.
Toothed belt replacement
The toothed belt on BMW vehicles is replaced every 80,000 km for safety reasons. Since errors in this work can lead to severe engine damage, the work must be done very carefully. To replace the alternator timing belt, see "Engine".
On a 524td diesel engine, the toothed belt needs to be tightened regularly every 40,000 km. In addition, check and, if necessary, adjust the static torque of the high pressure fuel pump.
External inspection of the exhaust system
Raise the car.
Check the reliability of the installation of the fastening brackets.
Use a carrying lamp to check the absence of chafing and burnouts on the muffler.
Replace badly deformed muffler pipes.
By stretching and bending the rubber suspensions, check that they are not cracked, otherwise replace them.
Every 60,000 km: Tighten the bolts securing the front pipe flange to the exhaust manifold to a tightening torque of 45 Nm.
Attention: Flange connections with return springs do not need to be tightened.