Sorry for all questions new to Miata. I just got a 1990 Miata and has about 150,000 on it. Since not know anything about when oil was change planning a filter and oil change. With being 150,000 miles was planing on just staying with probably 5w30 dino oil. Is this good wisdom?
thanks

 

Yes it is perfectly fine to use nonsynthetic oils in most any engine unless the auto manufactures specially states a "required" type of oil.

In 1990 full synthetic was extremely expensive as was synthetic blends. Most owners still used nonsynthetic oils in their vehicles. As synthetic oil became less expensive than the owners saw the affordability of them and started the newer trend to more readily use them.

As for the viscosity I recommend the use an oil chart to determine the best viscosity based on where you live and the operating ambient operating tempretures. .