A word of advice when searching the internet. E-How, How Stuff Works, Yahoo Answers, WikiHow, Ask.com and all the other so called answer sites are written by yahoos most of the time or people with no idea of what they are taking about. They look up stuff themselves without stating their sources, and then write it plagiaristic style so they look smart and get "points" or payment from the site. Take all those kind of answers with a grain of salt. I rely much more on the experience of the members here that I trust and can communicate with. Not speaking of TC's link, (Yesterdays Tractors I consider a good source) it just made me want to remind all. I never even click on those types, just known car guys, Company websites, scientific studies, Associations or other forums to read all the different opinions not just one answer by some actor.
I looked up all the decals I could find, all GM/AC decals said 50 wt. and many also said 20 wt. winter. Old ford decals said use same as engine oil. I always used same as engine oil back before paper element, That's what my dad did because we didn't have the luxury of running down to Napa. Just had one case of 30 wt. Havoline. Never had any smoke from engine sucking oil, fouled plugs or other signs of splish splash. I like Amsoil type systems now.
