Here are my final results: After two containers of this stuff, properly installed and run in (the second time after an oil change), it doesn't work as advertised. It did slow down the leak from my rear main a bit, but it's still leaking. The claim on the container that says "It really works" is inaccurate. It didn't for me. The two containers cost over $30.00, so when I determined that it didn't work, I sought a refund as their advertising says that it's "guaranteed". The NAPA store where I bought it refused to give me a refund, so I contacted the manufacturer. They asked a lot of questions and made it difficult to obtain a refund, saying that I had to go back to NAPA. This is after NAPA already refused to refund me. So I went back to NAPA a second time and a very unfriendly manager refunded me for the price of one container, acting very put out for having to do so. My recommendation: Do not buy Blue Devil Rear Main Seal repair. I was very disappointed by their product and the way they treat their customers.
