I have some Rotella Motor Oil sitting at home that was intended for another project. I just so happen to have enough for my next oil change in my WJ. (an '01 Jeep Grand Cherokee with a 4.7 liter). I always run WIX Oil Filters and for the past 30,000 miles I have started putting thicker oil in it (10W40 or thicker). It had developed some valve train noise more than likely from high mileage (140,000 miles).

Would it be a bad idea to use up the Rotella in my WJ for the next oil change? I don't like to change oil brands alot, I have been running the Ford Motorcraft synthetic blend for a couple of years now.

Let me know what you think.