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kozakvod · 08-18-2022, **(Subject: Crankcase Filter & MPG )**

SPECS: 2013; ISX15; CM2350; Deleted; 760,000 OD

When the delete was performed at approximately 180,000 miles ago (yes, from VERY reliable directions from this form). At the time of the delete I followed the directions here to utilize the new Crankcase filter that I just purchased by drilling a hole in the side of it, etc. and then never thought anymore about it. Not TOO long afterward, I began to notice a "hissing" like noise on acceleration, etc. It sounded exhaust like in nature, but in a continued search for something lose or whatever I could never find anything.

Jumping forward a year I noticed a steady decline in my MPG and granted that I'm a Auto Hauler in a 2014 Pete 388 flat nose with generally a big SUV back on over the hood I'm always pushing a massive amount of wind and my route is ALWAYS uphill out of north Texas into Colorado. Always windy and generally always between 80k - 84k gross.

Last week, I had a feeling in my gut that I needed to change the crankcase filter. Can't say why I had that feeling, but I had it none-the-less. I went by Rush and bought a maintenance free filter $151.00. Pulled the old one out, completely saturated, etc. and installed the new filter. Cleaned everything and buttoned up everything. Took a first load after the filter change to colorado and the first thing I noticed, that hissing noise was gone. Normally that run would require around 330 gals of fuel, I had began to slow down when the fuel started getting so stupid I dropped my speed to 60/61 mph, dropped another gear keeping my rpm's up around 1800 and my mpg jumped by about 1/2 mpg. After changing the crankcase filter and just finishing up my IFTA report for the trip my mpg was 5.85, which from the worst numbers a few months back at 4.5 or so is well over 1.25 mpg increase.

No I have noticed no other issues or problems, at this moment. Does this sound logical to any of you? I've done nothing different than to slow down and drop a gear, but as soon as I changed that filter there was a noticeable change in economy.