Are any of the Zmax products worthy of use? They can be used in the oil, transmission, and fuel for example. Check out their site. http://www.zmax.com/why/benefits/ And has anyone used them with results anything close to what they claim? I just thought it might be good for the old gal if I added something like this to my 40+ year-old engine and fuel system. Thanks for any and all input.
I dunno about zMax but I use Lucas additives. I keep track of my fill-ups and mileage and I notice a bit of a bump to my mileage every time I add it and then it goes down gradually until I add more. So like I add it, get about 2mpg and after about 3 fill-ups that 2mpg bump is gone. I've used some other additives like the STP and GUMout, and they tend to have no effect after that first fill-up. Also, I exclusively fill up at the cheapest seediest gas stations I can find.
I've used Zmax in almost every motor that I've rebuilt and that along with good oil that is changed often is cheap insurance................I have never used Zmax in the trans or rear end as feel it's not needed............................IMHO