Ok to switch back/forth from Dino to Synthetic?

[kscheffler]

I have a 40 Hp mercury 4 stroke 2002. I have both 10/30W regular dino oil and 25/50W synthetic oil. Both of these oils are mercury 4 stroke oil. I would like to run the heavy oil in the summer and thinner oil in the winter. Is it okay to swithch back and forth between dino oil and synthetic. I though I heard once that if you go to synthetic you have to stick with it?

[Orca]

Switch at will. No problems. One of those wife's tales. I would just run syn all the time. Better protection, and if something goes wrong with cooling and you overheat, you are more likely to survive it.

[fishkisser]

:yeahthat::agree:

[CRD4Liberty]

No need to worry about the syn in the winter it doesn't get thick in the winter like dino oil. Pours just as good in 10 degrees as it does in 70 degrees.