Would there be anything wrong with trying Mobil 1 10W40 high mileage in an older diesel application? Particularly, a 1997 Ford Powerstroke 7.3 DI turbo. A friend of mine told me that he would give me some of his leftover 5 QT jugs from when he owned a Volvo. I know that the M1 carries an API CF certification. The truck has a few leaks, around the oil pan, and either the turbo pedestal or the rear main seal, I haven't had time to chase it down. The truck just lost one quart of oil in about 1,500 miles and 3 months into the OCI. I don't think it's too severe, what do you guys think? If I can use the M1 HM, could it help with the leaks, or could it hurt? I have used HM oil with success in the past with gassers that burnt some oil, but never had a diesel before (although I used to drive an International 4300 w/ the DT466 and an Interntaional 4700 with the DT360 for work), or a leaker. Current fill is the new Valoline Maxlife 15w40. Thanks!