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JRMichler · 12-07-2015, 09:24 PM

That honey color, even in new oil, is dirt. Clean oil is transparent. I once designed a hydraulic system and specified a three micron absolute, full flow, no bypass, high collapse element. After running 18 months without an oil change, the analysis said the oil was good for continued service. When I looked in the reservoir, I could see the bottom through about 20 inches of perfectly clear transparent oil. That's why oil added to industrial hydraulic systems, even from a new container, is supposed to pumped in through a filter.

Motor oil has additives to counteract acids from blowby. Those additives get used up.

If you had an engine with really good filtering, analyzed the oil regularly, and added additives as needed, you could run the same oil forever. It's cheaper to just change the oil, though.

12-07-2015, 09:24 PM	#6 (permalink)
JRMichler Master EcoModder Join Date: Feb 2011 Location: Phillips, WI Posts: 1,018 Nameless - '06 GMC Canyon 90 day: 37.45 mpg (US) 22 Maverick - '22 Ford Maverick XL 90 day: 43.95 mpg (US) Thanks: 192 Thanked 467 Times in 287 Posts	That honey color, even in new oil, is dirt. Clean oil is transparent. I once designed a hydraulic system and specified a three micron absolute, full flow, no bypass, high collapse element. After running 18 months without an oil change, the analysis said the oil was good for continued service. When I looked in the reservoir, I could see the bottom through about 20 inches of perfectly clear transparent oil. That's why oil added to industrial hydraulic systems, even from a new container, is supposed to pumped in through a filter. Motor oil has additives to counteract acids from blowby. Those additives get used up. If you had an engine with really good filtering, analyzed the oil regularly, and added additives as needed, you could run the same oil forever. It's cheaper to just change the oil, though. __________________ 06 Canyon: The vacuum gauge plus wheel covers helped increase summer 2015 mileage to 38.5 MPG, while summer 2016 mileage was 38.6 MPG without the wheel covers. Drove 33,021 miles 2016-2018 at 35.00 MPG. 22 Maverick: Summer 2022 burned 62.74 gallons in 3145.1 miles for 50.1 MPG. Winter 2023-2024 - 2416.7 miles, 58.66 gallons for 41 MPG.