Detergents: Magnesium vs Calcium

[Direct_Rejection]

Not only does SonofJoe have great info, but he also articulates it in a manner that makes it interesting.

 

[CR94]

Originally Posted by Direct_Rejection

Not only does SonofJoe have great info, but he also articulates it in a manner that makes it interesting.

Agreed!

 

[bluesubie]

Originally Posted by Direct_Rejection

Not only does SonofJoe have great info, but he also articulates it in a manner that makes it interesting.

Originally Posted by SonofJoe

I'm no Walter White but if I was to hazard a guess, it would be this...

 

[emod]

Originally Posted by SonofJoe

Boric acid is a white crystalline solid & a rather weak Lewis acid. In an ashless dispersant, it will be weakly bonded to one of the basic nitrogen groups in the polyamine part of the dispersant. It could be that over an OCI, stronger acids formed by fuel combustion or the oxidation of base oil both displace & replace the boric acid on the dispersant chain. Now boric acid, unlike most of the stuff you find in oil, is water soluble. You'll always get a bit of water in the sump from condensed blow-by gas (especially when the engine starts in cold conditions) & maybe the BA preferencially migrates into it. This would result in a net loss of Boron from the main body of oil.

This is an excerpt from an article from Machinery Lubrication: "There are exceptions to additive depletion-measuring limitations of ICP. Most notable is the case of borate-EP-containing oil contaminated with water. In this case, the extreme pressure additive containing the boron settles out of suspension and forms a sludge at the bottom of the sump. If this precipitate is not captured in the sample, the boron level will read much lower than normal, indicating the oil is not fit for further use due to extreme pressure additive depletion. The converse, however, is still not necessarily true: if the boron level is correct, the oil may not necessarily still be fit for use." Source: https://www.machinerylubrication.com/Read/854/oil-analysis-tests (please see chapter "Limitation") So it seems that the reason for "missing Boron" is the water

 

[Shannow]

Good post.