In most climates it takes 5W-30.
A 2001 Chevrolet Trailblazer uses a STP Extended Life Oil Filter
anywhere from 10w30 -10w40
5w30 in the winter time 10w30 in the summer time Castroll GTX is a great oil to run.
5W-30 is Recommended.Regards HHH
5w30 conventional or synthetic is your choice.
10W40
A 2001 Chevrolet S10 2.2 liter engine will hold approximately 6 quarts of oil. The recommended oil type is 10 W 30.
20w50
on the oil pan
A typical type of oil filter for an Chevrolet Colorado 4x4 would usually when bought from a dealership or a car sales men would be a SYNTHETIC oil type filter.
It comes on when you need to change the oil.
5W-20 ( according to the 2001 Ford Mustang Owner Guide )