Amazing stuff! I bought this old Mercedes and quickly realized it constantly smoked when you hit the gas from start-up, I was ready to do a $800.00 Valve Stem Seal Replacement Job when my boss told me about this product! I put a quart in on top of my existing oil! and Instantly I saw a huge difference, now a couple weeks later, there is no smoke what so ever! I will add at every oil change. Thanks for the awsome product!