Originally Posted By: OceanRuns
I have several older Japanese vehicles. Oil information, like what's posted below, is similar in a few different owners manuals. This particular manual is from a 1983 Toyota Tercel wagon (3AC engine.)
On the back of the manual, it says to use 10w30 or 10w-40 in 'normal' temperatures.
However, on the viscosity chart inside, it seems to indicate that if you're driving in temperature that is ever in the 70s or 80s, you need a 50 weight? Wouldn't most people consider those temperatures in the 'normal' range?
I'd like to protect the engine. I currently have Delo 10w30 in there (partly for the 1200ppm level of ZDDP). Sometimes on the coldest winter day it is 30 degrees. Sometimes I go somewhere in the summer and it's 90s. Most days are 40s or 50s in morning to 70s afternoon.
Looking at this chart, does it seem like 50w is necessary of you're ever driving in 70, 80, or the occasional 90 degree weather? Or, is this chart a bit of a relic?
Thanks
Here’s what we think OceanRuns, we would recommend Shell Rotella T Triple Protection 10w30 or 15w40 Motor Oil. Besides considering what’s in your picture (API Grade and Vis/Temp graph), it’s also important to know that the Rotella product is formulated with a higher level of anti-wear agents for older flat tappet engines (as you’ve also mentioned in your write-up). - The Shell Rotella Team
