i run regular oil during the year. i want to know if i use synthetic oil during the winter can i switch back to regular oil once warms up, and then do that every winter and so on? thanks

Yes, but why? Most synthetics are compatible with petroleum.

i would rather use the synthetic in the winter,because the regular oil is so thick at start up.

I think RichLube was wondering why you would not run the synthetic year round. Many of us do with excellent results.

0W40 synthetic year round for me.

yes you can switch weights during the year. if you run a synthetic i would run synthetic year round then. im sure its ok to switch back and forth from synthetic to dino but the advantages of runing synthetics definatly outweighs the constant switch