I have checked the oil level and it's okay. I don't know if it is the oil pump or not, does anyone know how I can check to see if it is the oil pump? Has anyone had this problem before because I hear that the toyota sienna's are notorious for oil sludge build up which can lead to a bad oil pump.
Thankls johnny

Thoughts:

. Remove the oil sender unit and connect an oil pressure gauge, in order to check the pressure.

. Use 5W-30 full-synthetic engine oil (e.g. Mobil 1), to prevent sludging.