Oil guru's.....will a "synthetic" 5w40 HDEO shear more than a dino 15w40??? Some people tell me that a "marine" engine that runs constant high rpm's NEED'S a
15w40 oil to prevent shearing..but I thought that synthetic oils dont shear like dino oils do?? Also some old wise mechanics I speak with tell me that when "cold" 15w40 oils protect better because they provide a "cushion" upon startup (like honey on the moving parts) unlike a 5w40 that will "drain" off of engine parts like water. Please help me?? I have this BITOG addiction : , )
15w40 oil to prevent shearing..but I thought that synthetic oils dont shear like dino oils do?? Also some old wise mechanics I speak with tell me that when "cold" 15w40 oils protect better because they provide a "cushion" upon startup (like honey on the moving parts) unlike a 5w40 that will "drain" off of engine parts like water. Please help me?? I have this BITOG addiction : , )