GM E.O.S. states not recommended as an oil additive?!!?

[TallPaul]

Bump. Hopefully we will get an answer as to how much zddp is too much and in what relation or lack of relation to other oil components it is a problem.

Redline has (IIRC) about 1500 ppm zinc and phosphorus. Is that too much? Maybe that is part of the reason Redline UOAs don't show that well.

Or is it the sulfur content of the zddp that is the corrosive agent?

The graph in this link (at end of article) shows BMW SG oil running 1800 ppm zinc and little calcium. Seems to me that 2000 ppm should not even be a problem.

 

[TallPaul]

Here is a linked article that implicates sulfer as the component of ZDDP that can result in high copper in diesel UOAs. It describes the reaction that also can affect camshaft bushings. So it seems zinc and phosphorus are not the culprits, but sulfur.

So perhaps if enough zddp is added to a motor oil, it will become sort of like a gear lube, which we know is bad for an engine.

 

[BrianWC]

Hmmm, I wish we could get more input. Isn't a higher level okay, though, if a copper deactivator is used?

 

[ebaker]

The experts previously posted that ZDDP at diesel oil levels or slightly higher is a good number to shoot for.

 

[MolaKule]

Our testing and analysis shows that in certain gas engines, copper and iron wear starts to increase at a level of 1600 ppm of Phosphorus.

Increasing the zddp levels raises the phosphorus, zinc, and sulfur levels.

 

[TallPaul]

Thanks, Molakule.

So the recommended dose of most additives is fine for a SM or SL oil, but would be too much for Redline. Of course why would anyone want to additize Redline?

So VSOT, SX-UP, SLOB all are produced specifically for additizing oil, but EOS is not. Besides, why go with EOS when SLOB has about 2/3 as much zddp anyway?

 

[MolaKule]

Not necessarily, since it depends on the formulation and the engine; this is where UOA's and expert analysis come into play.

I don't see additizing Redline either.