Originally Posted By: Big O Dave
That is the very chart that got me to start this thread. If 0w20 and 5w20 are completely equivalent, they why would Toyota bother to differentiate between the two, in terms of vehicle compatibility?
I agree that in
theory the two should be interchangeable, but for some reason Toyota, in this case, doesn't think they are, and I would love to know why. Trying to get them to explain it is an exercise in futility.
I just find this whole 0w20 vs 5w20 discrepancy intriguing.
I don't think the above-shown chart is the product of marketing - what would be the purpose? There must be some sort of engineering reason that we haven't yet happened upon.
The 0W-20 and 5W-20 grades are ranges of viscosities.
A 0W-20 can be heavier at operating temperature than a 5W-20 and vise versa depending on the brand and the actual viscosity spec's for each oil.
The Toyota and Lexus oil charts are for their TGMO oils.
The conclusion I take away from the charts is that the TGMO 5W-20 is heavier, not just on start-up but also at operating temp's.