Toyota Corolla oil leak from timing chain tensioner due to loose rubber gasket on Toyota Corolla

Some Toyota Corolla owners report experiencing oil leaks from the timing chain tensioner, often attributed to a loose rubber gasket. These leaks can occur at the back of the engine, leading to oil seepage that may compromise the tensioner's pressure on the timing chain guide, potentially causing the timing chain to jump teeth on the timing gears. Owners are advised to inspect the area behind the pulleys for additional leaks, as oil may also seep from the crankshaft position sensor or the crankshaft seal behind the bottom pulley. When addressing this issue, some owners find it necessary to replace the o-ring or consider installing a new tensioner assembly, particularly if the vehicle has high mileage.