M103 oil pump longevity (loud valvetrain on startup)
Our 89 300TE (190K miles, Mobil 1 since 60K, original valvetrain) gives me pause on startup. Oil pressure gauge goes to 1 bar, and then it's 2-3 seconds until it reaches 3 bar on fast idle. You can hear the valvetrain clicking until oil pressure gets above 1 bar. Runs perfectly after that.
This is my first vehicle with this kind of mileage - any thoughts/experience on longevity of oil pump or other causes of this?