BMW E30 Timing Belt and Water Pump replacement
Timing belt is one maintenance item that should not be ignored on BMW E30 with M20 motor. If not changed in time, you might end up with bent valves or worse - and it will happen at most inopportune moment. BMW recommends changing timing belt every 60,000 miles or 4 years which ever comes first, however a lot of E30 owners change timing belt sooner, usually around 40k or 50k miles. Additionally, timing belt tensioner pulley is often replaced at the same time, and it is recommended to change water pump at every second timing belt change.
Timing belt and tensioner removal
Disconnect battery negative cable. Radio memory will be gone so if you still have factory radio make sure that you know security code in order to re-activate it afterwards. You can get the code from your local dealer. There are some aftermarket gizmos that will keep the power to the radio while the battery is disconnected, so you can use those as well.
Removing the hood is optional, however it will make the job much easier. Before removing the hood, first pop it open, and mark hinge locations with marker or paint pen. On the passenger side, there is a hose for windshield wiper nozzles that goes 'into' the hood. Follow it into the engine bay and disconnect it from the coupler. You might opt to remove the windshield washer fluid tank, or you can simply plug the hole on it so that washer fluid does not leak. While holding the hood in the raised position remove the clip, closer to the hood, from the foldable hinge that connects hood and passenger side fender. Push the hinge to the closed position; you can also remove the clip that secures gas strut and fender to make the job easier. Lower the hood but don't push it closed. From the front of the car, you will see six bolts - three per hinge. Remove those bolts, as well as grounding strap. It would be easier if you have one or two helpers to lift the hood, however one person can do it.
Choke rear wheels, jack up front of the car and place it on
jackstands. Make sure that car is securely positioned on them.
If your BMW E30 has one, remove black plastic splash shield from underneath the car - it protects radiator and accessory belts.
Coolant can be drained next, so make sure to have suitable catch pan. Open coolant expansion tank cap, and remove lower radiator hose. Be ready to catch the coolant. It is not absolutely necessary, but it is good idea to drain the coolant from the block. To do so remove the 19 mm bolt located on the passenger side of the engine, under the exhaust manifolds and just aft from the oil filter.
Remove cooling fan from the water pump. For this you will need 32mm open end wrench. Fan is held on the water pump by a nut which has left handed thread. So to loosen it, looking from the front of the car, turn the wrench in the clockwise direction. You will have to give quick tap to the wrench in order to break the nut free. Give a tap by a rubber mallet if you have one, otherwise you can use your hand but it might hurt. Once the nut is loose, spin it and remove fan from the water pump shaft. There are two clips located on the side of the fan shroud. Unclip those, and remove fan and shroud. Make sure not to drop the fan, and store it in the upright position.
Before disconnecting coolant hoses, it might be helpful to make a
note of how they are arranged. Disconnect and remove coolant hoses
from radiator and water pump.
Before removing the radiator, first disconnect the electrical
harness(es) for the temperature switch(es) from the radiator. Remove
two mounting bolts and lift the radiator. Pay attention not to loose
rubber grommets, nor metal sleeves that are in them.
Next step is to remove cap and rotor. The black protective shield is held in place by three bolts. Unfasten them, and tuck the cap out of the way. You can remove spark plug wires, however it is not necessary. If you do so, mark them so that you don't mix them up upon reinstallation. Rotor is removed by loosening three mounting screws -some models need torx bit, while others need allen key. Be careful not to 'round' the screw head. Once the rotor is removed, dust shield can be removed as well.
Water pump pulley is held in place by four 10 mm bolts. Loosen the
four bolts, but just enough to break them free - don't remove them,
nor excessively loosen them - just break them loose, maybe half a
turn (this will later make pulley removal easier).
Crank pulley is held in place by six 13 mm bolts. Again, just break these bolts free - don't remove them nor excessively loosen them.
Loosen and remove power steering, AC, and alternator/water pump belts. Make sure to loosen the mounting brackets nuts/bolts, and not to strip toothed bracket.
Remove the water pump pulley by unfastening four 10 mm bolts - ones that you 'broke free' earlier.
Unfasten and remove six 13mm bolts that hold crankshaft pulley and vibration damper. If the crank still wants to turn as you are removing the bolts, place 22 mm socket/wrench on the crank nut, and hold it in place while removing the six pulley bolts. Remove the pulley, but leave vibration damper in place; it's located via dowel pin, so even if you remove it you can always put it back in the proper location.
Upper camshaft cover is held in place by two bolts 10 mm and 13 mm. Unfasten the bolts and remove the cover and engine hoist bracket.
Now it's time to set piston No 1 to TDC (Top Dead Center) position. Place 22 mm socket or wrench, on the crankshaft nut and turn it clockwise until the mark on the camshaft sprocket, usually an arrow or an indentation, lines up with the notch on the head. In the example picture notch on the engine head is a line located at about 2 o'clock position from vertical.
When those cam marks are aligned, the marks on the vibration damper and lower timing cover must be aligned as well. Vibration damper has "O | T" mark that should align with the notch on the lower timing cover. Remember, one full crank revolution corresponds to two full cam revolutions. Just to emphasize the point - make sure that both sets of timing marks, cam and crank, are aligned. If you turned the crankshaft too much, such that marks are not aligned, just keep turning the crankshaft in the clockwise direction until the marks are perfectly aligned. Note that removing sparkplugs will make the job of turning the crankshaft easer. Now that the No 1 piston is at TDC, make sure not to move crank or cam in subsequent steps. Following pictures illustrate examples of crank timing marks on M20B25 ("i") engine and M20B27 ("eta") engine.
Remove the crankshaft damper. Although it might look that damper is
held in place by the crank nut, it is not.
Remove the lower cam cover. It is held in place by 13 mm bolt.
Loosen, but do not remove, the upper bolt that holds tensioner pulley. Next loosen the lower tensioner bolt - it is on the same stud that holds alternator bracket (thin 15 mm one).
To relive timing belt tension get a long screwdriver and push the
tensioner, in order to rotate it, towards the pass side of the car.
Holding the tensioner in that position, tighten the upper bolt.
Remove timing belt, by sliding it off from the pulleys and the sprockets. This is not hard but take your time, and work in clockwise direction starting from camshaft sprocket.
Now that the timing belt is off, start to remove the tensioner pulley by slowly removing upper tensioner bolt. Be careful that the guide pin and spring do not fly off. Once the bolt is removed, take out the guide pin and spring. Remove the lower bolt and tensioner pulley as well.
Water pump removal
It is recommended that water pump be replaced at every second timing
belt change. At this stage it is very easy to do, as the water pump
is held in place by three 13 mm bolts. Remove the bolts, and the
water pump will be free to come off.
Now would be a good time to clean front of the engine. Clean the area where water pump gasket was at, as well as any dirt, oil, etc., at the front of the engine.
Timing belt and water pump installation
Put new water pump gasket and water pump back on. Torque the three
bolts to 22 +/- 2 Nm.
Get new timing belt tensioner pulley (make sure that it has "Z 127" stamped on it), and hand tighten the lower bolt. Install guide pin and the spring. Make sure that the pin is securely, and properly, positioned in the water pump notch. Rotate the pulley towards the passenger side, and hand start the upper bolt. Pay attention to the pin tip, as it should engage hole in the pulley assembly. Using the long screwdriver, push the pulley all the way to the pass side, and tighten the upper bolt so that it locks the pulley in the position.
Next step is to put the new timing belt on, but before you do so, re-check timing marks and make sure that they did not move. Start putting the new belt on the crankshaft sprocket and work in the counterclockwise direction (crankshaft sprocket, intermediate shaft, cam sprocket, and tensioner pulley). Assure that the timing belt is tight between each sprocket. It might take a little practice, but only use your hands to do this, and not tools such as screwdrivers, etc., as you don't want to damage sprockets or the timing belt.
Once the timing belt is properly positioned, slowly loosen, but do
not remove, the upper tensioner bolt. The tensioner will rotate
towards the driver side and engage the timing belt.
Loosely put the lower timing cover and vibration damper (located via dowel pin) back on, as you need to check timing marks.
Using socket or wrench on the crankshaft nut, in the clockwise direction rotate crank between two to four full revolutions. Recheck the timing marks. If they do not align, you have to remove the timing belt, align the marks and put it back on again.
Torque upper and lower tensioner pulley bolts to 22 +/- 2 Nm.
- Tighten the camshaft cover bolts: 10 mm to 10+/- 1 Nm, and 13 mm to 22 +/- 2 Nm
- Six crankshaft damper and pulley bolts to 22 +/- 2 Nm
- Four water pump pulley to 9 +/- 1 Nm
- Three ignition rotor screws to 3 Nm
- Install and tension alternator, AC, and power steering belts
- Radiator mounting bolts to 9-10 Nm .Don't forget to reconnect the electrical connections to the sensors at the top side of the radiator
- Fan nut - remember that it is a reverse thread so it should be tighten in the counter-clock wise direction. Give the wrench final 'whack' with rubber mallet or hand, although the proper torque is 40 Nm
- Don't over tighten hose clamps bolts / screws
- Torque block darin plug to 50-56 Nm
- If you removed the hood, put it back on, install six hinge bolts making sure to install the ground strap, and clip(s) for the folding hinge. Use alignment marks that you made before to properly align the hood
- If you removed sparkplugs, tighten them to 25 +/-5 Nm
- Add water-coolant mixture to the overfill reservoir
- Bleed the cooling system - add water-coolant mixture into the expansion tank, until it reaches full mark. Inside the cabin, turn heat control knobs to full warm. Start your E30, and let it idle and warm up to normal operating temperature. Loosen the 8mm bolt on the thermostat housing and let coolant mixture run out until there aren't any bubbles in the stream. Tighten the bolt, let the engine cool, and add water-coolant mixture to the expansion tank, until it reaches 'full' mark.