The only negative side effect that I have experienced is oil leaks. 3 out of the 6 vehicles that I have treated have developed oil leaks. I did also notice some oil consumption, I don't know how much was from leakage and how much from some other cause. Oil stains on the driveway are the result, not damage of any kind to the engine that I can tell. Because treatment with ARX occurs gradually over a period of time like a month or even more depending on how much you drive the vehicle, the oil leakage can be slow to develop and slower to subside.
I haven't been able to tell where the leakage has been coming from either. Two of the cars I suspect it is coming from the valve covers because of a burning oil odor from the exhaust when the cars heat up real good. I had no oil leaks before ARX treatment.
I thought the leakage might be related to the age or number of miles on the treated cars, but my highest mileage vehicle that was treated is a '96 Olds minivan and it uses no oil and leaks no oil onto the ground. The 3400cc 6 cylinder in it has been very reliable and peppy, a real pleasure to own.
