Just cut open my PF53 oil filter after my 500 mile run on first dose of Auto-Rx. I have cut open numerous filters at work for T-Shooting purposes and I have never seen what I saw tonight. I could literally scoop the dirt and sludge out of the filter media with my pocket knife. It looked like a filter that had never been changed. Could not believe all the crap that came out with just 500 miles. Currently the oil guzzling beast is using approx. a quart per 500 miles. Hopefully after the second dose and some 10w-30 Castrol High Mileage it will subside. 131,000 miles on engine, 3rd owner. Beater car back in forth to work, 86 miles round trip.