[LifeTech]

Oil consumption is from a leak or blowby.

Blowby can occur at the Piston rings or at the Valve guide seals and thus burn with the combustion out the exhaust.

Leak may be external or worse...internal..but rare.

I say it is not the type of oil....

I say yu may have purchased a sludge engine. It was that way when yu bought it. It doesn't matter what oil yu are using the probelm was there from the get go. I don't trust dealers word at time of sale. Never.

I have spotted many Toyota 3.0 sludge engines on used car lots before.

The oil may appear clean...but the heads is where this developes first due to the "bad" Toyota Crank case Ventilation design of these early 3.0's.

A sign of sludge would be heavy darkening of the oil just about 1-2K miles after an oil change.

I would say that 1/2 qt loss from normal piston ring Blowby is acceptable for 112K miles but no more. Definitely not from the Valve Guides. That's never good.

Using Mobil 1 or most any Synthetic subsequently will "clean up" this varnish and sludge, however the Wear that this sludge condition created prior cannot be reversed by using a synthetic. Thus the abnormal oil usage.

Oil additives are NG. And will never help in any regard to this.

My thoughts

LT