im curious if any of them reduce smoking problems? I have about 120,000 miles on a rebuilt 2.9 in my 1988 ranger, its been smoking for the last 80,000 miles, big puff of blue when it starts then not so bad when im driving but gets really bad if I idle at stop lights. I don't have the money for another rebuild, the engine seems to run fine, just wondering if anyone has used a product that helps? thanks.

 

Might be your valve stem seals. You might be able to replace them without pulling the heads. Easier w/o AC, still tough with the right tools:

https://www.therangerstation.com/for...acement.90021/

Thicker oil will slow it down a little, but there is no additive that will put valve seals back together, and there is no additive that will add material to the cylinder wall.

Old engines that sat for years with stuck rings can be loosened up, but that's not what's happening with your motor.

 

Kinda sounds like valve stem seals, so you might try a "High Mileage" oil recipe, to see if the seal conditioners can soften up & improve their grip on the valve stems to slow the weeping. Also make sure the PCV valve is working. If you have excessive piston ring "Blow-By", along with an acting out PCV valve, the blow by can over pressure the crankcase & force oil past the weakest seal & if the weakest seal is the valve stem seals, it'll seep right into the combustion chamber.

If compression is down from stuck piston ring land deposits not allowing the piston rings to float free, you might try removing the spark plugs, add a couple Tablespoons of Marvel Oil for a weekend long Marvel oil piston soak. Then crank the engine over to expel any excess Marvel Oil, to prevent hydro-locking the engine, before re-installing the spark plugs. Some thoughts for consideration, let us know what you try & how it goes.

 

I agree with the valve stem seals being the likely problem and agree with the seal conditioner suggestion. In my experience the amount of seal conditioner in high mileage oil is likely not high enough to eliminate your problem, but there are additive bottles of seal conditioner that might do the trick if you use one with each oil change. I have used "Bearing Seal" but your parts store should have several others.