Lifter Tick Bad?

One lifter failing is rare. All of them clattering is the result of something in common which is low oil pressure, often due to low oil level and the pump is sucking up air. Have you checked the oil level?

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.

If it's just one, I'd wait to see what happens with thicker oil. If that solves the noise, I'd continue running that oil in cold weather. I have one in my '88 Grand Caravan that's so loud, people get out of my way in parking lots for fear of falling parts! It's been doing that for over five years. I use 10W-40 year round because it is a REALLY high-mileage engine.