Originally Posted By: CATERHAM
Well the Amsoil 5w30 is much lighter than M1 0W-40 so that may have something to do with it.
For the next oil change you could try M1 5w30 and see if the noise increases.
Originally Posted By: mechtech2
New knock sensors, fixed PCV system , and new thinner oil.
You'd be crazy NOT to notice a difference!
Originally Posted By: mrcoolguy
The pcv system was fixed at the start of the new oil though! and I ran the M1 0W40 for a week after the knock sensor was fixed and it felt about the same as before. This is what puzzles me!
If the sensors were flagging a CEL or you had to reset the ECU, maybe its a result of noise from the ECU re-learning it's relative information and coincidence?
You'd figure dropping a grade would have the opposite affect...maybe your oil change had some chatter from the oil filter? Did you change that?
But seriously it could have been the computer adjusting to properly functioning knock sensors and coincidence after your oil change.