I started using additives to reduce startup smoke so I could pass emissions. Moved away from emissions test area and kept using the additives as I didn't like a big blue cloud when starting, a bit embarrassing. Now that I am back in testing area I dont want to be called in for smoking. The additives work so I almost have to keep using them or go to a $$$ smoke free oil. Its cheaper to just buy an additive.
I am sure my next vehicle, if the Land Cruiser ever dies, will have high miles as I dont want to make payments, so I would like to know if there are affect of using additive.
If using smoke reducing additives have no affect on the rest of the engine I will keep using them but it does have negative affects, it would be cheaper in the long run to just fix the problem.
The smoke started about 250,000 mi but was very minor blue puff. At 350,000 it got embarrassing and I started dealing with it with additives. At that time I had no idea that the motor would keep going at 400,000 mi let along 436,000 mi.
I would not think twice about foxing valve seals with under 300,000 mi but opening a motor with almost a half million miles could cause more problems than just dealing adding additives.
The oil combo that made the least smoke was MOS2 10w40 with Motor Oil Saver but it was too thick for winter use and got costly. Now that the oil is getting thinned out from the blowby, I will be going to a 3000 mi +/- oil change interval. Not sure what oil and additive to use.