I recently changed the oil in a friends 5.3 GMC Sierra with high mileage (over 200,000). He has been having what sounds like a sticking or failing lifter. He has been getting his oil changed every 5,000 miles at Pep Boys with whatever 5W-30 conventional oil and jobber filter they use. This time I had several 5 qt. jugs of Castrol Edge 10W-30 (A1-B1) that I bought on sale, so I used that and 1 qt. of Traveler 15W-40 to make up the 6th quart along with a Fram Ultra for this oil change.
After start up and warm up the engine clatter stopped. It occasionally returns for short intervals but he reports it has almost completely disappeared. He now wants me to keep changing his oil with Edge 10W-30!
I have always been skeptical of folks who claim a certain oil is makes their engine quieter, but in this case it is certainly true.
So what say you? Is it the oil or the filter that stopped the clatter?