[WorkinLonghorn]

Further info from factory service manual;

It lists 3 types of "air-cleaners"; 1) "oil wetted paper element", 2) two element air cleaner, and 3) oil bath.

" The two element air cleaner utilizes an oil sump in the air cleaner bottom and a fibre element"

"On most applications of the two element air cleaner it is used in conjunction with an exhaust manifold heat stove". -goes on to describe the system-

From this I would assume that oil bath and oil wetted paper air cleaners did not use heated air. My Freemont Calif '69 1/2 ton sold in Calif. had the air pump but no heat stove.