I've used AutoRX on 4 vehicles. On the Jeep and my 300Z it made no significant improvement-but I didn't expect it to. It was more for preventative maintenance.
On 2 other vehicles it made a big difference.
8N Tractor and Nissan Sentra
Both engines saw a big benefit from the AutoRX treatment. Granted-I didn't take the engines apart for before/after pictures. However the compression test on the tractor showed that something sure cleaned things up-most likely rings and valves. The only change other than the tune up was the AutoRX treatment.
On 2 other vehicles it made a big difference.
8N Tractor and Nissan Sentra
Both engines saw a big benefit from the AutoRX treatment. Granted-I didn't take the engines apart for before/after pictures. However the compression test on the tractor showed that something sure cleaned things up-most likely rings and valves. The only change other than the tune up was the AutoRX treatment.