Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Been using this for years

I love this stuff in my cars. Keeps my cars going strong even after 140K miles. I use it in my gas tank, intake manifold and during oil changes. I recently opened up my valve cover in my old Camry to replace the gasket and found a clean cover. Zero gunk. I don't use it that often between oil changes, but do use it more often(every 4th oil change) cleaning the upper section through the intake manifold.