Lucas oil conditioner/stabiliser?

[Tazling]

Engine Oil Stop Leak – Lucas Oil Products, Inc. – Keep That Engine Alive!

www.lucasoil.com

I saw 4 litre jugs of this product line in my local parts store -- it claims it can reduce smoking in old diesel engines, and my 1968 (?) FL-120 is definitely an Old Smokey so I was tempted.

But it sounds a bit like snake oil -- too good to be true? -- so I was wondering if anyone else has tried it. Is it just another scam, or is there anything to it?

 

[Lepke]

My guess is that it adds heavy oil and an additive to soften the seals. If they still sell it, you could do as much with a can of STP. The theory is thicker oil will not get by the rings as easily.
Your engine smokes because oil is getting by the rings. Maybe, but not as likely oil is getting by the valve guides. If the smoke is black it could be a bad injector allowing too much fuel.

 

[Tazling]

Hi, thanks for the info. Smoke seems more gray/bluish to me than black. looks pale against the water, for example. I did switch from multigrade to straight 30 on the advice of old fisherman buddies, but it doesn't seem to have helped any. the valve guides were checked and redone last time the head was off (for a gasket), also injectors sent out for reconditioning. that was about 18 months ago so I think those things are most likely OK and it must be the rings. it's a very old block and I'll bet it's been rebuilt at least once.

 

[Lepke]

It doesn't matter how old the block is. Or even if it's been sleeved in the past. Unless the block is warped out of shape or big cracks, any block can be rebuilt.