Running lean meaning?!

If you watch your gauges...on a long hill pull, the oil pressure drops because the extra heat does a number on the oil viscosity. That’s where the oil stabilizers like Lucas makes the difference. The oil pressure will not drop very much at all when you run a gallon of Lucas in the crankcase. I run it. I may run 2 gallons in the summers.

 

The isx motor loves mobil delvac. Or the delo 400. Lucas not needed

Anything else will sound like a tank, run hotter, take longer to cool down, gasket leaks, decreased fuel mileage. You'll need lucas to help out.

I once drove an 05 w900 with isx. It had a label on the frame for mobil delvac. I was actually purchasing the truck from the company till the company decided to close the doors. I had a chance to use other brands. Always went back to mobil delvac. If that wasn't available. Delo 400.

One brand oil that the company used because it was cheapest. Was really bad oil. It was soo bad heads were constantly being replaced. Engines ran hotter and wouldn't cool down. I had the only truck in the fleet that never got a new head. The one time the truck used it. Threw most of lt out the gaskets on a 700 mile trip. 8 gallons mobil were added before it stopped leaking. I won't mention the brand but it's not a commonly available oil around the country.

 

So will dumping a gallon of gear oil but who would run a 350 with 80% gear oil .. that’s more or less what Lucas is...

 

Honestly if your even thinking about using Lucas forget it. And use 80/90 gear lube it's cheaper and "actually" has additives for high pressure and such.
I've never saw a diesel that ran lean. Being that a diesels can idle at 50 parts air to 1 part fuel. I've only has injectors go bad and inject to much fuel. But I guess an injector going bad and not injecting fuel is a possibility.

 

Sell that truck fast and go back to work as an employee.

 

Who are you saying that to?