If I filter my used engine oil can I dump it in the fuel tank & burn it off in my 2004.5 truck? With dino oil getting close to $9 per gallon, it's hard for me to toss it away.

 

I've seen a Cummins document that said that it was possible to run low percentages of used engine oil that had been properly filtered and/or centrifuged. The reasons given were to permit fleet managers a viable and low cost alternative to disposing of used engine oil. But I imagine that if DC ever suspects that you did this and you take the truck in for warranty work - don't be surprised that they blame all of your woes on running your new truck on used engine oil.

Whether or not you want to risk your brand new engine with burning used engine oil is a personal decision. Fuel here is only $2.60/gallon; You might save a few bucks in the short term, but if your filtering process is so-so and permits the entry of chunkies, deposits, and what not, the long term costs could possibly outweigh any short term savings.

I think I saved it at home, and can check later.

Try a search, this has been discussed many times.

 

It may plug the cat, Cummins recommends against mixing WMO in the fuel for engines with a cat.

 

Why would it plug the cat? What's in engine oil that would not burn/pass thru? Any issues running vegetable oil in a truck w/ a kitty?

 

Just relaying what Cummins says. If you are dead set on doing it, keep the ratio low (a couple quarts per tank) so it gets burned completely.