How to Replace a Timing Belt on a 1990 BMW 325i

The timing belt on the E30 generation of the BMW 3 Series should not be neglected. If the timing belt fails, it can cause major engine damage. Though BMW recommends that the belt be changed every 60,000 miles, many owners actually do it sooner--at around 40,000 to 50,000 miles--for added insurance.

Tools Used: Floor jack, Jack stands, Socket set and ratchet, Screwdriver, Container for coolant, New coolant, Timing belt kit

Replace Timing Belt

Disconnect the negative cable (the black one) from the battery. Remove the bolts that hold the black plastic splash shield on under the car. Remove the shield.

Open the lid for the coolant expansion tank. Drain the coolant from the block into a container by removing the 19-mm drain bolt under the exhaust manifold on the passenger side just behind the oil filter.

Remove the cooling fan from the water pump with a 32-mm open-end wrench. The nut has left-hand threads so turn it clockwise to remove it. Store it in an upright position. Remove the fan shroud by unclipping the two clips that hold the shroud on.

Remove the coolant hoses from the radiator and the water pump, noting which hose goes where and what orientation they are in. Remove the two mounting bolts that hold the radiator in place and remove the radiator.

Remove the three bolts that hold the distributor cap in place, and the cap. Loosen the three mounting screws that hold the rotor in place and remove the rotor and the dust shield underneath it.

Loosen the four 10-mm bolts that hold the water pump in place. Loosen the six 13-mm bolts that hold the crank pulley in place. Loosen and remove the belts for the power steering, A/C and alternator/water pump.

Finish removing the water pump bolts and remove the water pump. Remove the crank pulley bolts and the crank pulley. Leave the harmonic damper (behind the pulley) in place.

Remove the two 10-mm bolts and one 13-mm bolt that hold the upper camshaft cover in place. Place a 22-mm socket and ratchet on the crankshaft nut and turn it clockwise until the mark on the camshaft sprocket (an arrow or indent) lines up with the notch on the head. Check that the "O/T" mark on the harmonic damper lines up with the notch on the lower timing cover. Both sets of timing marks MUST be aligned.

Remove the crankshaft damper. Remove the 13-mm bolts that hold the lower cam cover in place. Loosen the upper bolt for the timing belt tensioner pulley. Loosen the lower tensioner bolt. Rotate the tensioner towards the passenger side of the car with a screwdriver to relieve the tension on it. Tighten the upper bolt with the tensioner in the loose position.

Slide the timing belt off of the pulleys and the sprockets in a clockwise direction, starting at the camshaft sprocket. Remove the upper tensioner bolt, the guide pin and the spring. Remove the lower bolt and the tensioner.

Install the new timing belt tensioner pulley and hand-tighten the lower bolt. Install the guide pin and the spring. Rotate the pulley towards the passenger side and install the upper bolt. Push the pulley all the way to the passenger's side and tighten the bolt.

Double check the timing marks and adjust if needed. Install the new timing belt, working in a counterclockwise direction. Make sure the belt is tight between each sprocket. Loosen the upper tensioner bolt, which should cause the tensioner to rotate to the drivers side and engage the timing belt.

Loosely install the lower timing cover and harmonic damper. Check the timing belt marks by rotating the crankshaft with the socket two full turns. Check the marks. If they are off, remove the belt and reinstall it until you get the marks lined up.

Tighten the upper and lower tensioner pulley bolts. Reinstall the camshaft cover, water pump, belts, radiator and fan belt. Reinstall the distributor cap and rotor. Reinstall the radiator hoses, the drain plug in the block and top the engine with coolant. Reinstall the splash shield.

Post a Comment