Wow... 100,000 miles drain interval for diesel? Did she say how often she
changed the oil? Even with 100K miles, you still have to do the regular oil
100,000 miles drain interval must be synthetic... Call them up and
confirm... plus find out how much that stuff cost. Mobil Delvac 1 is also a
very pricy stuff.
How bad of oil leak? You have to determine whether those expensive oil
draining out onto your driveway is worth it. If it is like valve cover
gasket, you can change them...
People with diesel swears by constant 3000 miles oil change with normal
oil... SAE30 in summer and 15W40 in winter. All 15W40 oil are designed for
diesel engine but can be used in gas engine. They are both thick oil.
The reasoning is the combustion waste is detrimental to engine because the
additives get saturated that it cannot provide anymore
This make me wonder about the oil... I believe it is specifically designed
for long distance fleet truck in mind... where it is all highway driving...
plus they have these super huge oil filter... size of your quart milk
container and two of em! Not only that, they have I believe 5 gallon oil
capacity ( I am not sure about this... but near that amount or higher)
My advice is call up that company and ask. Otherwise, switching back to dino
oil probably will stop that oil leak you have... unless that is a mechanical
problem like bearings.