Replace every 30,000 miles (20,000–50,000 km depending on plug type).
The 5AFE valve cover uses rubber gaskets at the cam caps and rubber half-moons at the ends. Novices slather RTV everywhere, clogging oil return passages. The manual clearly states: "Apply sealant only to the camshaft bearing cap corners and the semi-circular plug." toyota 5afe engine service manual new
For those performing a rebuild or top-end repair, the following torque and maintenance data is frequently sought in a service manual: Cylinder Head Bolts Introduction Spark Plugs: Replace every 30