Originally Posted By: dave5358
Originally Posted By: demarpaint
I never heard of moly increasing your OCI, where did you find that out? I've read, heard, or experienced everything else you mentioned, but I was unaware of it having the ability to increase an OCI for fleet owners. BTW I'm not disputing what you said, it was something I wasn't really aware of.
You may be going into this the wrong way. Molybdenum Disulfide (MoS2) is not a new product. It's been used in a variety of industrial processes since at least the first World War. One use is as an alloy of steel, but a another use is as a lubricant. In this latter case, Moly does two things: reduce friction (and thereby reduce heat) and it helps avoid catastrophic failure in the event of oil loss (the 'plating' effect). Logically, if you reduce friction, you might get some better mileage or efficiency, but I've never seen that claim from any responsible source.
Back in the 1960's and 70's, VW of America specified it's use in air cooled engines, in which the engine and transmission shared a common oil supply. My understanding of this use was to reduce heat (and no other claimed benefit). In fact, most VW dealers did not use the product and more than a few air cooled Beetles overheated - particularly in America.
During this same time frame, Eazor Express Corporation did a fairly extensive study of the use of MoS2 in OTR truck hydraulic systems. I apologize, but I cannot find a copy of the study or even a reference to it. The result of their study was that using MoS2 as an additive increased the fluid change interval and service life of the hydraulic systems by a significant amount - say 5-7% (something of that magnitude). For a fleet operator, this was a big deal and their conclusion was that moly was a cost effective additive. For the consumer or passenger vehicle, it is not so clear.
In more recent times, there seems to be some consensus that the use of moly in engine oil will reduce oil usage past the rings in a gasoline engine. This is not inconsistent with the Eazor Express findings. Moly clings to other metal surfaces, such as rings and cylinder walls and bearings. It will stay in place, even if the oil is drained. To a more limited extent, it will stay in place if the oil is drained and replaced. But, the moly coating is temporary - you must add some additional moly with each oil change or it will eventually go away.
As a humorous aside, during the 1960-70's hype of 'miracle moly' one ad featured a demonstration wherein a vehicle (with moly in use) had the engine oil drained. Then, with no engine oil, they drove the vehicle for 25 miles! See, doesn't that prove that moly is great stuff?
Back on planet earth, there seems to be consensus that moly provides good start-up lubrication. That should not be surprising - the 'plating' thing. Since much engine wear occurs during the first few minutes of operation, this might be a significant matter. But it still may not be cost effective for an individual consumer. With no additive, your engine may last 100,000 miles or more. How much more would you be willing to pay for the engine to last 150,000 miles? 200,000 miles? 400,000 miles? Most people I know get new-car-fever (or change-car-fever) long before their engine wears out. And don't expect the taxi-cab fleet owners to test for this either - their vehicles rarely get turned off.
Finally, moly in engine oil reduces heat by some amount - a few degrees. VW engineers simply used a standard industrial lubricant to attack their heat problem. They might have added a bigger oil cooler - and later did! Plus, there were a zillion after-market oil coolers made for Beetles. But, then VW changed the design of their engines, eliminating the shared oil supply. Eventually they did away with air cooled engines altogether. For water cooled engines, the cooling system and lubricating system is designed to handle the heat load.
Will moly in engine oil save gas? Probably yes, but I've never seen a credible study for this. Simply because no one has tested for this property should not suggest one answer or another. Moly as an engine oil additive is a low sales volume product. Don't expect a million dollar study of this application (or any moly application) anytime soon. It's not going to happen.
Thanks for the explaination! I'm a moly user and believer, and knew the history etc. I was unaware of the additional perk of being able to extend the OCI by using it. I noticed in certain applications a smoother idle, and reducing smoke in a worn engine. I believe the plating actually can fill small imperfections in the cylinder wall, which is why people make these claims. That could also explain why some people see a mpg improvement. In a new or pristine engine people won't see these benefits because there is nothing to improve upon. However the reduction in wear is always a plus, and will be noted later on. Thanks again for the reply!
