1989 Toyota Camry V6, auto trans, 198k miles
Added zmax engine treatment, transmission treatment, etc. last month.
The good: Before adding zmax it would require 2~3 minutes of warm-up idling or the transmission wouldn't shift gears. It has much improved since adding zmax and transm shifts much smoother. Thumbs up.
The bad: 19-21 mpg on average before; 20.2 mpg on the first tank of gas. Where's that promised increase in mpg?
The ugly?: My car used to leak about a quart of oil between every oil change. A bottle of $2 engine stop-leak took care of it a few months ago. Added zmax last month, drove it around, and the leak came right back, smoking like a barbeque grill under the hood. Try telling me it's a coincidence.
i've been a mechanic for over 20yrs.when you have a leak additives are not the solution.have the bad seal replaced.these additives act like a synthetic oil that has been added to an engine that has always run on standard oil.it cleans out the sludge that builds up inside an older engine,which in turn cleans out the seals,thus your return of your leak.
i would also like to add that if your engine is close to 200.00 miles,you might want to think about increasing the viscosity of your oil.of course the manufacturer wants you to stay with your 5W30 motor oil.they want to sell you a new engine or a new car.