I recently changed my oil and now I'm hearing a slight knocking sound. I was running standard Castrol 10w-30. After hearing all the talk about new oils losing zinc and cam failures I decided to switch to Castrol High Mileage 10w-30, Lucas Oil Stabilizer, and some Cam Saver additive. After changing the oil and filter I took the car for a short drive. When I returned home I thought I heard a slight knocking sound. I drove the car about 40-50 miles yesterday evening and can still hear it.

Could the engine be rejecting this new blend?

Should I switch back to the former oil or switch to a heavier weight oil?

Should I leave out the Lucas Oil Stabilizer?

I'm pretty confused. Any help will be really appreciated.

 

knocking like the rods or tapping like the lifters? I really do not think a change of oil mentioned and it effected the rods so fast, that would have to have been a preexisting condition, if it is lifter noise that is something else... I don't know, I always used 20-50w in my car

 

It appears to have smoothed out somewhat. But if anyone else has any thoughts I would truly appreciate hearing them.