Originally Posted by 89ford73

nobody ever told the man about the big nut thing thats leaking on the oil pan, just get big pliers and tighten it up. i have fixed quite a few leaks like that.

Originally Posted by pjwoolw

It will just make it worse.

Originally Posted by Muktown

Thought id follow up and let you guys know how my first change with shaffers went. Was using rotella syn and changing it at about 3500 miles because it would shear with the dual pumps and a noticable difference on how the truck ran so I tried schaffers 5w 40 syn and changed it at 4500miles with 3200 of those towing 8k to florida and back and the rest plowing. UOA came back perfect and told me to increase my interval to 6500 and check it again. Considering its cheaper than rotella im very happy with it!

Originally Posted by F250_

William has offered some excellent responses to some key issues. I'll only respond because I've run both Amsoil 5w40 and Schaeffer 9000 series 5w40, both full synthetics.

I'll also be up front and say that I am a Schaeffer rep, but I will not push our oil. I am an engineer first, and my goals are long life and reliability with my personal vehicle. Even though I rep Schaeffer, if I find a better or more cost-effective product, I'll be running THAT in my vehicle. Now, I only became a rep AFTER running the Schaeffer for over 2 years in my truck and seeing the difference, and only started using the Schaeffer product AFTER running the Amsoil and seeing its lack of long term performance in my engine.

More context... I am running a 2 micron Racor bypass oil filtration system, and that was in place BEFORE I started using either Amsoil or Schaeffer. I change both the main flow filter and bypass elements at every oil change.

My personal goal is to get as long of an oil change interval as possible without paying through the nose, losing additive activity, sheared down viscosity, or wear metals starting to climb. Any demise of either of those last three characteristics is the limiting factor on how long I run my oil. At this point, Schaeffer is the cheapest option I've found due to the length of life I get from it without compromising my engine's performance or life.

On Amsoil, when I hit 13K miles, the oil had already sheared down to a 30w and my iron levels were climbing. I had already decided to try the Schaeffer before that point due to what I had heard about their oil, and switched. I am now at 18K miles between changes with everything (additives, viscosity, etc.) holding up... don't know if I can get much further until I get my latest samples back from the lab. If we were running either a D-max or a Cummins, we could get even longer life out of the oil because neither of those engines are nearly as bad on oil shear as the Ford 7.3, and the Ford 6.0 is the worst on shearing oil.

Technology differences do exist between Amsoil and Schaeffer (since those were the OP's point of interest). Both use the same types of high grade synthetic products, and both use good additive packages with extreme pressure additives being one of two main reasons for extra oil life. The second main reason for longer oil life with these products is the quality of synthetic oils being used which are more temperature tolerant and viscosity-stable.

The extreme pressure additive packages in Amsoil and Schaeffer are not the same, though. In addition to having the same zinc as Amsoil, Schaeffer has two additional extreme pressure additives which Amsoil does not contain - molybdenumdisulfide (a soluble form of moly which cannot get filtered out, even at 1-2 micron levels of filtration) and proprietary additive that was developed by Schaeffer in the 50's or 60's (no one else in the world even has access to to this additive).

Regarding the Schaeffer moly package versus the Amsoil zinc package... you might be thinking, "So what?" Well, here's the reason why the difference is significant. Though zinc is a good extreme pressure additive, the metal-to-zinc bond can be broken much more easily (~ 250,000 psi) as compared to the metal-to-moly bond (550,000 psi), and that means that when you punch your throttle and cause your shaft to slam the top inner surface of your main bearings, you will break that zinc bond and end up with metal-to-metal wear in a zinc-based oil. However, in contrast, the strength of the metal-to-moly bond is so great that there is almost no wear under the same conditions because the moly is not knocked loose from the metal surfaces. since the moly stays in place, it continues to work as a dry lubricant (preventing metal-to-metal contact) even when engine forces case the oil to get completely squeezed out from between rotating components. You end up with both lower friction inside your engine and less metal-to-metal contact.

Now... all that being said, I have had great success with Amsoil in my gas engines, but it just didn't live up to its advertised capabilities in my 7.3. As for Rotella T6 (their 5w40 synthetic), if I could not get the Schaeffer product, I would run the Rotella T6 because the Amsoil is not that much better in comparison to the cost difference between it and the T6.

Originally Posted by vjpastore