What are opinions on Lucas Oil Additive?
A local mechanic suggested this for our 1978 Pinto.
He also suggested HEET for gas tank.
? Thoughts?
All the Lucas oil conditioner does is increase the viscosity like STP or Motor Honey. I don't know why your mechanic would recommend that. Proper oil doesn't need additives and can actually be negatively affected by them.
HEET is just alcohol intended to absorb moisture in gasoline and allow it to stay suspended so it doesn't freeze or cause running problems. The yellow bottle is straight methanol and the red one is isopropyl alcohol and some kind of petroleum additive. Again, I don't know why a Phoenix area mechanic would recommend fuel line antifreeze/drier.
Sea Foam was mentioned; it is effectively a small amount of rubbing alcohol suspended in naptha. It doesn't do anything for the engine, it has no effect on the ethanol in fuel, and certainly is not a fuel stabilizer. The ethanol in pump gas already does more of whatever cleaning effect the isopropanol in Sea Foam might have.
Most of the universal "fix-all" additives on a parts store shelf don't work as advertised. A few do, though, like Sta-Bil and Royal Purple Max Boost.
The safety data sheet (SDS) for these products usually provides a good idea of what the major components are.