Krex oil additive??

That's a rule of thumb created by a greedy oil industry

 

That was way back, now the greenhouse gas reduction efforts and all the dependency on foriegn oil, not to mention the global warming issues and now theyre trying to change the old way of thinking.

 

In the old days of carburetors, leaded fuel, non-electronic ignition systems the standard oil change interval WAS 3,000 miles. But with computer controlled, electronic fuel injection where the fuel/air mixture is so precisely measured it's much longer. You don't have that cylinder "wash down" when starting the vehicle.

The vehicle I just replaced was a 2010 F150 with their 4.6L 16V V8. It was basically the same engine in the Crown Vics. It had 255K when I traded it in. I changed the oil on it every 10k using either semi or full synthetic oil and a high quality filter such as a Wix, Motorcraft, K&N, Bosch, or a Mobil 1.

The truck never smoked or used oil, the timing chains were rattling was the reason I traded it. Was using 5w-20 and 5w-30 oil until the last 10k, had to finally use 10w-40 to keep the hydraulic chain tensioners pumped up so the chains wouldn't rattle.