I want to try an oil additive for helping with bad rings. What are your suggestions. My son's 2001 Xterra, with a 3.0 L V6, suddenly started consuming a lot of oil (3 quarts in 750 miles) and the oil is very black after a short interval (~ 200 miles). He has had the truck for only one year and has about 100,000 miles at this point. We have changed the oil and filter twice with 10W-30 M1. He took it to the dealer who checked the cylinders with a borescope and proclaimed the boeres are scored and he needs a new engine. He is away at college and needs to keep driving the car until the spring, when I will rebuild the engine. A local mechanic suggested an expensive oil additive that contains Silicone but he couldn't remember the name. Please help.