[email protected] I just traded for a beater. It is a 1981 Dodge Omni. Actually, seems to run pretty good. I just changed the oil and added Havoline 5W/20 because that's what I have in stock. Reading the owner's manual, it states that you can use 5W/20 in cold climates. Funny, I thought 5W/20 was something new. Didn't know they had it back then. The manual does specify "DO NOT use 5W/20 for sustained high speed operation". Back then, the oil was rated SG. The oil I just added is SM rated. Am I o.k. to run SM rated 5W/20 in this engine or should I go to something heavier?