Good day all.. pre cleaner question I wasn’t sure about and the manual didn’t detail to my satisfaction.. This is probably one of those things the CAT manual people figured everyone had to know that! No need for micro detail.. so does any oil go into the small upper jar??  I cleaned out probably an inch of hard muck from the large bottom. Interesting the oil above was still pretty clean looking. Thank for any thoughts of the small upper jar. Appreciate all the Caterpillar brotherhood.. AND happy retirement if Mary sees this. She helped me years ago getting onto here.

Nope!, it's just a dust and bug collector, well......maybe a John Deere once in awhile. Check and clean the screens in the bottom of the filter housing and the inner tube. Oil [30W] is used in the bottom cup of the housing.

Ok .. will do..thank you for the input.. previous owners had put oil and ..it was hard chunky about half full of pieces similar to the bottom gunk..no liquid.

If you look at the bottom of the upper pre cleaner, you will see the air is started to swirl by a set of fins. Because of the swirling motion of the air the heavier dirt particles are thrown to the outside of the precleaner where they are directed into the jar and not into the actual air filter. This causes the oil in your air filter to stay cleaner for much longer. There are many variations of this type of system still in use now.

Per Tactical Driving School, Fort Sam Huston/Camp Bullis (Sp?) (1964), oil bath air cleaners:

Remove oil sump.
Pour oil into ~clean pan.
Carefully scrape gunk from sump pan and wipe with rag.
Pour removed oil back into sump pan.
Add fresh engine oil as necessary to 'full' mark.
Reassemble.

Daron
 

If you have that much dirt in the pan and jar (sounds like a lot of accumulations) - you might like to take the whole assembly off and ensure the "screen" in the body of the air cleaner is not packed solid.
I have seen that many times where no one has cleaned the inner workings, just limits the cleaner ability to capture more dirt and restricts air flow.
Those oil bath systems depended upon oil on the screens to help capture the dust - a long way from what the dual element Dry filters do today!

Be sure to check the hoses and fittings for seal - any restriction in the air cleaner will make those leaks, on the engine intake side, take more dirt through -bypassing the filter system.

CTS

Great info.. thanks to all.. I will be following advice..

many used to use old sump oil not a good idea as it has all sorts of crap in it.

the same basic idea is still used to day cyclonic seperation to remove most of te dust before it passes to the element. to days precleaners are plastic rather than metal. the original filters were made by the donaldson company which are still going today.

occasionally its a good idea to soak the screens in warm diesel or kerosene to clean them sloshem up and down and let em drain. steam cleaning would also work well

Dot Not steam clean the screens in the filter body, there is a Cat service bulletin on them that states not to steam clean them because it "balls up" the dirt and lint like material and stays in the screens.

Hi All, I have let screens soak in diesel over night, come back in morning to see black liquid hiding screen within, then drip dry for a while and blow out with air then install again, the system surely works well.