Procedure
- Confirm the leak is actually the covers: oil pooled in the plug tubes and drips at the cover's rear corner are the giveaways. Wash the area and drive a day if unsure.
- Driver side needs the battery out; passenger side the washer bottle. Remove coil packs and unclip harnesses along each cover.
- Remove the perimeter 10mm bolts, noting lengths and positions, and break the cover free with a palm strike - never pry against the sealing surface.
- Peel the old gasket and tube seals. Clean both surfaces to bare metal with brake cleaner; any oil film will re-leak.
- Seat the new gasket into the cover groove dry, with a rice-grain dab of RTV only at the half-moon corners where the cover meets the cam cap seams.
- Press new tube seals in square. Reinstall and torque the perimeter bolts in a cross pattern to spec - these are in-POUND values; overtightening splits the new gasket.
- Reassemble, run to temperature, and check the rear corners with a mirror. A correctly torqued cover stays bone dry.
Work at your own risk. Torque values and procedures vary by vehicle — always confirm against the factory service manual for your exact model.