Packard Forum Index » V-8 (1955-56)

A very good solvent to use in cleaning oil bath (and oil mesh) air filters is charcoal lighter fluid, it's an isoparaffinic hydrocarbon, essentially an odorless and more refined version of kerosene. It's sold industrially as Exxon's Isopar G or H. I prefer it because it doesn't affect the paint on the housings which gasoline can, depending on the paint type. A quart is more than adequate to clean a filter and the crankcase oil filler breather and the residue is just disposed of with waste motor oil. You Based on the condition of the filter, for me cleaning once every 5 years seems about right.

Let me add one more note on caring for these filters.

VW specified that unless the oil bath filter element is visually restricted it does not require cleaning.

Thus, only dump and wipe the oil bucket on the VW filter.

By 1952 Packard specified cleaning the reservoir only.

Especially if detergent oil is being used.

Thanks Tim, that Packard advocated only cleaning the resevoir was something I didn't know. Both my Packards have the Oil Bath air cleaners & I had never seriously considered changing to paper. Now I have even less reason. to.
It makes sense. Before WW II even new Packards could expect to see some use on non paved roads and the air filters could get pretty filthy as a consequence. By the 50s, the number of miles a new Packard could excpect to travel on unimproved surfaces had probably dropped to double digits - even fewer as they aged so doing the "clean element in fresh gasoline then re-oil monthly" bit was no longer relevant.
I remember when Mount St. Helens blew in 1980 the Portland area TV Stations ran pieces advising car owners NOT to change air filters and leave them in until performance was seriously affected as a dirty filter does a better job of keeping volcanic ash out of engines.

From Wikipedia on the types of papers used for air filters:

The raw materials are different paper pulps. The pulp may be from softwood, hardwood, fiber crops, mineral fibers. For high quality filters, dissolving pulp and mercerised pulp are used. Most filter papers are made on small paper machines. For laboratory filters the machines may be as small as 50 cm width. The paper is often cr?ped to improve porosity. The filter papers may also be treated with reagents or impregnation to get the right properties.

I think the confusion over oil bath cleaner service comes from the fact that the mesh filter element has to be cleaned in gasoline and oiled, but the oil bath element does not. After all, no matter what solvent is used, if the oil bath element is soaked in solvent, the motor will be injesting fumes, running rich, and diluting the oil bath.