[Sid60ish]

Just my two-pennorth. With a background of 34 years in the oil industry and 30 of those in Lubricants, there is, I believe a common stance with vehicle manufacturers and lubricants producers. Engines, gearboxes. final drives, hydraulics et al have designated requirements for lubrication in terms of viscosity, performance level and oil-change intervals. These are arrived at after huge amounts of formulation and testing in a cooperatrive effort between builder and oil producer(s). Oil formulations are put together to suit the application and sometimes the engineering is modified to improve things, ( I was involved with one manufacturers engine which has still not come to market after 12 years. The metallurgy was so off the wall that it could not be successfully lubricated to last more than 15 minutes on a test bed). The relevant oil specs then appear in the handbooks and both the manufacturer and oil suppliers will stand by their products as specified in the correct environment. Once you add anything to the lube oil you lose the backing of both the vehicle manufacturer and the oil producer. You have, in effect, introduced a whole new formulation which no-one has tested and which may, or may not, work as required.

Your best safeguard is to buy the best quality oil - THAT MEETS THE CORRECT SPECS - that you can afford and stick to the manufacturers drain periods............although these tend to be conservative. Why pay £30+ for good oil and then bastardise it with an additive that was never meant to be there and which may be doing more harm than good ?

I'm afraid I'm in the Snake Oil camp on this.