How to Replace Spark Plugs in a BMW 525


1. Use the flat-head screwdriver to gently pop off the two plastic covers, which are about the size of a quarter, that hide the bolts that secure the plastic cover over the engine head. This large plastic cover runs the length of the engine and has the BMW logo on it.
2. Remove the plastic oil-filler cap and loosen the bolts that connect the engine cover to the engine block.
3. Remove the large plastic engine cover to expose the spark plugs.
4. Remove the hex bolts that secure each 'BREMI' plug to the top of the spark plugs. The BREMI plug is the BMW equivalent to the standard boot that most domestic cars use to attach the spark plug wires to the tops of the spark plug. Remove each BREMI plug from the top of the spark plug by gently pulling it straight off the top of each plug. Leave the spark plug wires attached.
5. Use the spark plug socket wrench to extract the spark plugs from the engine block one at a time.
6. Replace each spark plug by tightening it loosely into the engine block with the socket wrench. Tighten each spark plug fully with the torque wrench to the specific torque setting listed in your owner's manual.
7. Replace each spark plug wire one at a time by removing them from the back of each BREMI plug and unplugging both ends of the wire, replacing it with a new one.
8. Replace the BREMI plugs back to their original location on the top of each spark plug.
9. Replace the large plastic engine cover, oil cap, and re-install the cover back on the engine block with the two mounting bolts.
10. Replace the two small plastic covers that hide the mounting bolts.