Opti-Lube XL Xtreme Lubricant Diesel Fuel Additive: 1 Gallon Without Accessories, Treats up to 1,280 Gallons

I have a 1993 f350 7.3idi diesel, just ticked over to 354k miles (or maybe 454k miles, if you know, you know). Since i started using the XL stuff, it's massively increased my mileage to a little over 30 mpg at 55mph on a natural aspirated 7.3idi. I am leaning in between standard and premium treatment I admit. Just about to order my second gallon

This stuff simply rocks! Over 500k on the original pump, and only my second set of injectors. That's good lubrication!

I have a 2007 classic lbz Duramax with 370k miles, using an additive like hotshots helped immensely, by quieting down injectors and increasing low end torque. But, switching to optilube has made it feel like a brand new truck, instead of a slightly healthier high-mile rig. I use the xl lubricant along with the cetane boost, as I live in the south and don't need any anti-gel. Within the first 5 minutes of driving home after filling up with fuel and adding the optilube, my injector tapping was gone completely. All of my lost power was back, as I could break the tires loose shifting into second again. With the garbage ultra-refined diesel that is sold today, these additives are absolutely a requirement for extending the life of your injection system. I recommend the same additives to my friend with an 03 lb7, and he was also blown away by how much healthier his truck was.