Notice on the SuperTech 5W-30 bottle, it doesn't list SG in the specifications. Only SM, SL, SJ.
The 93 Maxima service manual says to use SAE 5W30 SG Rated.
Here's something I found on the ratings:
PETROL
SG - Introduced 1989 has much more active dispersant to combat black sludge.
SH - Introduced 1993 has same engine tests as SG, but includes phosphorus limit 0.12%, together with control of foam, volatility and shear stability.
SJ - Introduced 1996 has the same engine tests as SG/SH, but phosphorus limit 0.10% together with variation on volatility limits
SL - Introduced 2001, all new engine tests reflective of modern engine designs meeting current emissions standards
SM - Introduced November 2004, improved oxidation resistance, deposit protection and wear protection, also better low temperature performance over the life of the oil compared to previous categories.
Note:
All specifications prior to SL are now obsolete and although suitable for some older vehicles are more than 10 years old and do not provide the same level of performance or protection as the more up to date SL and SM specifications.
The 93 Maxima service manual says to use SAE 5W30 SG Rated.
Here's something I found on the ratings:
PETROL
SG - Introduced 1989 has much more active dispersant to combat black sludge.
SH - Introduced 1993 has same engine tests as SG, but includes phosphorus limit 0.12%, together with control of foam, volatility and shear stability.
SJ - Introduced 1996 has the same engine tests as SG/SH, but phosphorus limit 0.10% together with variation on volatility limits
SL - Introduced 2001, all new engine tests reflective of modern engine designs meeting current emissions standards
SM - Introduced November 2004, improved oxidation resistance, deposit protection and wear protection, also better low temperature performance over the life of the oil compared to previous categories.
Note:
All specifications prior to SL are now obsolete and although suitable for some older vehicles are more than 10 years old and do not provide the same level of performance or protection as the more up to date SL and SM specifications.