Owned it basically since new... 5w30 always in dino then switched to high mileage around 150k. Looses about a qt per 1k. Mostly through leaks. Runs and sounds great. Need an oil change, been using Pennzoil HM 5w30 for the past couple years. Any reason to change or keep on with the same? It's in beautiful shape and has a newer trans, suspension is new, etc, it's staying with me forever.