synthetic oil

[mike smith]

i have heard there are basically two types of synthetic oil
class 4 which is regular oil reblended with additive package Like Mazda oil which i use mobil 1
class 5 true synthetic oil castrol

is class 5 better ( using same 0-20 weight oil) and changing according to manf recs

Topic

[Ingvar]

So you have a “blend” and then you have “pure” synth. What is that you are driving that you are concerned about this? Unless it’s a high end Mercedes or something, I wouldn’t be worried about minor differences in lubrication. Or a super charged motor with nitros.
COST is more of concern as if you have oil taking engine, it will cost you arm and leg in refills.

[Daniel Weith]

I think you may be referring to the ILSAC standard GF-5 which is for 2011 and older vehicles, and may be used in all previous applications prior.

The other standard is the API SN standard introduced also in 2010 to include use in E85 automobiles, and is suitable for use as a replacement for all previous API “S” standards.

0W-20 oil is only available as a full synthetic and only the latest API-SN and ILSAC-GF-5 should be used; if the certification logo on the back is SM or GF-4 it is old oil. If the application is for a 2010 or older automobile the previous standards are acceptable for use.

[Author]

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