Kreen is an amazing product, I have used it on my E300 diesel with almost 300k miles, to clean the engine, I added a quart and drove 500 miles, the goo that came out was unbelievable. I also had injector knock as well. All gone after one treatment, I followed it by another treatment for next OCI. I then started adding 4-5 oz to my 21 gallon tank at each fill up. Donated the car to my nephew who now has 340k miles and the motor has no issues, leaks etc. You will not regret it. Keep us informed.