Hello I have a 2008 Dodge Ram power wagon with 59000 miles on it . Owned since new change the oil twice a year around 3000 miles . Used amsoil 0w20 till 20k never burned any but didn't tow. Then switched to pennzoil ultra and started to tow and burn a quart every 3k . For the last year I have used Napa syn 5w30 but it burns a quart every 1200 miles or sooner . No leaks at all . Pcv is new . I'm not light on the pedal when towing . Pulling a 20 foot boat weighs around 5k. Thinking about rottela 5w40? Any ideas ? Thanks