Before starting this repair, you must have the following required parts.
Section 1 - Removing the Intake Manifold
In order to perform a BMW E46 starter replacement, the intake manifold must be removed. This should not be an intimidating process...in fact we urge home mechanics to look at this as an opportunity to install new manifold and throttle gaskets, as well as replace old vacuum lines that are prone to leaking.
For detailed step by step instructions on removing the intake manifold for this repair, please see our article BMW M52 Intake Manifold Removal – 1995-2000 3,5,7,Z3 Series 6 Cyl.
Section 2 - Removing the Starter Motor
The BMW E46 starter motor mounting bolts are notoriously difficult to remove from the engine for two reasons; there is very little clearance to get a socket wrench squarely on the head of the bolts, and the bolts are usually seized from age. These two conditions can create a recipe for disaster if you are not careful...you can strip the mounting bolt heads. We have found the best method
for removing the starter mounting bolts is to use a long 1/4" drive swivel head ratchet
, with a 3/8" adapter
and E12 external torx socket
. The reason why you must use a 1/4" socket wrench is that the head on a 3/8" wrench is too large....it will not allow the Torx socket to fit squarely on the head of the bolt. It is also important to use a long handle ratchet in order to get the proper amount of leverage to loosen the bolts. If used correctly as shown in the below steps, you will be able to safely extract the mounting bolts without any issues. If you need to order any of these tools prior to starting this repair, we have the same ones we used in the above tool list.
- Locate the BMW E46 starter motor. It is located at the rear of the engine.
- Use a 13mm socket wrench to remove the positive battery cable and alternator cable from the starter solenoid.
- Use an 8mm and 10mm socket wrench to remove the two wiring harness leads from the starter solenoid.
- Using a metal pick or small flat blade screwdriver, remove the coolant line on the side of the engine block. Have a 5 gallon drain pan ready to catch any coolant that comes out.
- The starter is anchored to the engine with two E12 torx bolts. Before attempting to remove them, spray both bolts liberally with Blaster PB penetrating oil and allow to soak for 5-10 minutes. You may need to apply the penetrating lubricant several times if the bolts are seized (see next steps). Not pre-soaking the starter mounting bolts with penetrating lubricant could cause the heads to strip during removal.
- Using a long 1/4" swivel socket wrench with 3/8" adapter and E12 torx socket, remove the first mounting bolt as shown below. If the bolt is seized, proceed to the next step. If you are able to remove the bolt, proceed to step 8 below.
- If the bolt is seized and won't break free, spray it again with penetrating lubricant and allow it to soak for a few minutes. Using a ball peen hammer, gently tap on the bolt 10-20 times. Keep repeating this process until the bolt breaks free and can be removed. Be patient...it may take some time. We had to repeat this procedure 6 times before our mounting bolt finally loosened.
- Repeat the above steps on the second mounting bolt.
- When both mounting bolts are removed, grasp the starter and remove it from the engine.
Section 3 - Installing the Start Motor
Installing the new starter is a simple process except for one caveat. It is virtually impossible to get a torque wrench on the starter mounting bolts...there is simply not enough clearance to get the wrench in place. This raises the issue of proper torquing of the bolts. As we have always said here at the BMW Repair Guide, sometimes an important procedure within the repair must be changed or adapted to avoid more complicated circumstances. In this instance, "guessing" at the final torque values of our starter mounting bolts presents less of a risk than dropping the transmission so they can be tightened with a torque wrench. In simple terms, make your starter mounting bolts as tight as you can without stripping the heads and you will be fine.
- Install a new starter motor back into the engine. Make sure the mounting holes are properly aligned.
- Install the mounting bolts and tighten as much as possible without stripping the heads. You unfortunately will not be able to get a torque wrench on them. (see our discussion at the beginning of this section).
- Reconnect the engine coolant line. Make sure to put firm pressure on it until it clicks into place.
- Reinstall the two wiring harness leads and torque their nuts to 6 Nm (4.5 ft-lb).
- Reinstall the positive battery and alternator cables. Torque their mounting nut to 12 Nm (9 ft-lb).
- Reinstall the intake manifold following the procedure in our article BMW M52 Intake Manifold Removal – 1995-2000 3,5,7,Z3 Series 6 Cyl.
- Refill the coolant reservoir and check to make sure there is no air in the system. For more information on refilling the coolant system on your BMW E46 3 series, please see the end of our article BMW E46 Water Pump Repair – 1998-2006 3 Series – All Models.
BMW E46 Starter Replacement Finished