What are the steps for removing and installing the valve cover on a BMW 523 inline 6-cylinder engine?
4 Answers
The steps for removing and installing the valve cover on a BMW 523 inline 6-cylinder engine are: 1. Remove the air conditioning intake cover on the left side of the engine; 2. Remove the ignition coils and fuel rail, and disconnect the wiring harness; 3. Remove the valve cover screws diagonally from the sides to the center, and use a flat-head screwdriver to pry the valve cover loose. Taking the BMW 5 Series 2012 523Li Leading model as an example: it is a mid-to-large-sized car with a body length of 5039mm, width of 1860mm, height of 1471mm, and a wheelbase of 3108mm. The front suspension uses a double-wishbone independent suspension, and the rear suspension uses a multi-link independent suspension. It is equipped with a 2.5L engine model N52B25, paired with an 8-speed automatic transmission.
Disassembling the straight-6 valve cover on a BMW 523, I share my experience as a seasoned mechanic. The engine must be completely cold before starting to avoid burns or component deformation. Disconnect the battery's negative terminal to ensure electrical safety. Remove the ignition coils and intake piping to create space and avoid obstructions. Then loosen the valve cover bolts in a diagonal sequence, removing them from the center outward, and record their positions. When removing the cover, proceed slowly as old gaskets often stick—use a plastic scraper to clean residual adhesive and oil stains. Thoroughly clean the cylinder head contact surface and the interior of the cover, using a lint-free cloth with alcohol for degreasing. Apply a thin layer of high-quality sealant (RTV silicone) to the new gasket and carefully align it. Reinstall the cover, tightening the bolts evenly in a diagonal sequence with a torque wrench according to the service manual specifications (approximately 8-10 Nm). Over-tightening or incorrect tightening order can cause oil leaks or cover cracks. Finally, reassemble the components, reconnect the battery, and test-run the engine to check for leaks. Ignoring oil leaks can damage the engine—inspect the valve cover every 50,000 km during maintenance.
DIY Enthusiast Perspective: I enjoy handling the maintenance of my BMW 523 myself. When removing and installing the valve cover, first ensure the engine is completely cooled—wait about an hour and disconnect the battery negative terminal to prevent sparks. Prepare the necessary tools: a socket wrench set, torque wrench, new valve cover gasket, sealant, and cleaner. Remove the ignition coils and surrounding intake pipes to clear the working space. When loosening the bolts, start from the center and work diagonally, and take photos to remember the sequence for easier reassembly. After removing the cover, patiently clean off the old gasket residue, using gasoline to wipe the surface smooth. Apply some sealant to the new gasket, press it flat during installation, and be careful not to wrinkle it. When reinstalling the cover, tighten the bolts evenly to the torque specified in the manual, increasing the torque in two stages to the standard value. After reassembling the parts, start the engine for a few minutes to check for oil leaks. If there are no issues, the job is done. This step in regular maintenance is simple but saves on repair costs. If you lack tools, you can rent them.
As a beginner doing this for the first time, I'm a bit nervous, so I'll explain from a simple perspective. The engine must be completely cold before working on it, wait at least half an hour before starting. Disconnect the negative battery terminal for safety. Remove the ignition coils, tubes, and other accessories. Carefully loosen the valve cover bolts in sequence without losing track of their order. After removing the cover, clean off all old gasket residue thoroughly before installing the new one. Apply a small amount of sealant when fitting the new gasket and tighten properly, but don't overtighten the bolts. Finally, reassemble all components and test for oil leaks. If unsure, it's safer to seek professional help to avoid damaging the engine. These are the basic steps—take your time and prioritize safety.
