some information about Borate esters to discuss:
"Ashless multi-functional additives are currently being developed as possible alternatives to ZDDP. However, their reactivity with water has limited widespread use. Reaction of the boron-containing additives with water results in the liberation of oil-insoluble boric acid that can cause corrosion in the engine. Approaches to improve hydrolytic stability have been developed, but have not always proven satisfactory@
from book "Lubricant-Derived Ash – In-Engine Sources and Opportunities for Reduction " by Simon A.G. Watson
"Borate esters possess friction-reducing, antiwear, and anti-oxidant characteristics when blended in lubricating oils. However, borate esters are susceptible to hydrolysis. The formation of a stable five-member ring structure in the ester molecules, involving coordination of nitrogen with boron, contributes substantially to the resistance to hydrolysis of borate esters. The susceptibility of borates to hydrolysis can be reduced by introducing N,N-dialkylaminoethyl groups with alkyl radicals containing more than three carbon atoms."
from book "Borate esters used as lubricant additives" J. B. Yao, Q. L. Wang, S. Q. Chen......
This information makes me worry - oil in my engine and a lot of oils today are using borate esters..
sorry fo my english