I run Castrol GTX 40wt year around, I’ve put 50k hard miles on mine so far for a total of 176k. If my engine were new with the tight tolerances I would run Castrol GTX 30 wt year round. I personally don’t buy into the multi weight scam especially since I live in CA and on 100 degree days all that multiweight oil thins out so much it all runs out of your bearings and upon restart you can hear things clanking you shouldn’t. Remember when it comes to CAR info from the established Manufacturer Engineers its all about getting your car worn out sooner so your back to buy a new one. That's how we get corrosives in brake fluid, Corrosives in antifreeze, Additives that goop things up, and you buying thin oil for warm days. You think they run these thin multi weights in race cars? Think they run thin oil in race cars? They run some pretty tight tolerances in their motors too but they don’t run these oils. An oil pump is a very powerful mechanical pump and as long as your oil is liquid when you start it up cold it's going to move oil to where it needs to be regardless of viscosity to a point. Most of the race teams have what they car Oil Parties where they dump the sponsoring oil out and put the brand and weight they prefer in their sponsor’s bottles. Now if I lived where it snows I would certainly run thinner oil, but I would change back to thick oil come the beginning of spring.
Rick
