I suppose it's possible, but to be sure, have the actual pressure tested with a mechanical gauge. If it's low, go back to the thicker oil at the next oil change or you can add a can of "viscosity index improver". That is a product such as STP. If the pressure is okay, the thinner oil could still be leaking out of the lifters faster than normal and allowing them to collapse and rattle.
Don't overlook the fact that a lot of people mistake the normal sound of clicking injectors as lifter noise. They're easy to hear under the hood but usually not with the hood closed.
Saturday, August 20th, 2011 AT 3:24 AM