Oil - Type of

[josediaz311@gmail.com]

The GM 216ci and the 235ci recommended oil is SAE 50. SAE 50 is practically not available.
What SAE oil equivalent can I use on our 216ci?

[Deve]

I use a semi-synthetic 10W30 (Royal Purple) in all of my trucks. The weight has more to do with lat/long coordinates and how cold it gets in your area. There is no perfectly correct answer that will satisfy everyone on this question. I like that my oil is Purple and my Gear Oil is Clear so I know what is leaking on my floor if anything by just looking at it.

[josediaz311@gmail.com]

I assume that Royal Purple is a trade mark, right?

[Deve]

Yes. I don't think it matters the brand myself.

[josediaz311@gmail.com]

Thank you. Stay safe in this virus environment.

[Dusty]

The shop manual recommends sae 10 winter and sae 20 summer . I am unable to obtain those oils here , so I use 15w40 and have done for 40yrs , with complete success . I think 50 weight oil is much to heavy unless your engine is pretty badly worn out (stuffed)

http://chevy.oldcarmanualproject.com...51ctsm0002.htm