Review on Genuine Toyota 90311 45014 Type T Timing by Brandon Burnham

After a few years, microscopic particles in engine oil can wear down the groove on the crankshaft on the front seal. This T-seal will move slightly where the seal contacts the crankshaft, but just enough for the seal to make contact with undamaged metal. If you've replaced the front seal (with or without the oil pump) and you're still leaking oil, this is probably the solution you're looking for. , and they're both as dry as can be. Changing your oil regularly and using a good quality oil filter (10,000 or 15,000 mile rating) will make your oil a lot cleaner and delay the formation of that groove on your crankshaft unless you have a leak (yet).