Originally Posted By: OilGuy
Here are some facts to consider:
Syntec cannot protect a rather common Cadillac, which requires an oil that is approved against GM's high performance oil spec, GM4718M. Castrol intentionally misleads the public to believe Syntec is approved, but they are not on GM's approval list. (It does satisfy the requirements of GM's conventional-level oil spec GM6094M)
Syntec is not approved against Acura's new performance oil spec HTO-06 required for the RDX.
In the industry standard test (TEOST) to evaluate high temp deposit resistance, Syntec creates 5x more deposits than M1. We may not experience such severe test conditions in our everyday driving, by it's an industry standard test to compare apples to apples.
Which Castrol are we talking about here?