can i use SG grad oil in my car
Short answer, if your owners manual has a letter grade of lower than SG, yes, oil is ‘backwards compatible’. From PQIA website:
Step 1: Go to your owners manual to find which oil is required for your engine. This will usually reference an API specification such as SN, SM, SJ, etc, and such ILSAC specifications as GF-3, GF-4, GF-5, and/or other specifications. Also look for the viscosity grade recommended for your engine (i.e. 5W-30, 5W-20, etc). You need to know this information - write it down. If you can’t locate your owners manual, an excellent resource for information on where to go for an online version is [Edmunds.com]
(http://www.edmunds.com/ownership/howto/articles/120189/article.html).
Step 2: Go to your favorite retail outlet with your list of engine oil specifications in hand and read the labels on the bottles. Make sure the oil you purchase meets the specifications in your owner’s manual. If you do not find the proper specification “codes” on the bottle don’t buy the oil. It’s that simple.
Step 3: If you have the oil changed for you at a fast lube, new car dealer or other service center, bring your list of specifications with you and confirm that the oil they put in your car complies with the specifications required for your car.
Actually that page only shows the viscosity requirements.
I do not know what the API top grade was in 2008.
Hence my answer.
SG grade oil was specified for cars in the late 1980s to mid 1990s. Manufacturing tolerances have improved a lot since then. I would not use this oil, which has likely been sitting around for many years, in anything newer than 1997.