Oil filter inspection

[cl65ame]

Experience. No need for analysis. The oil, although black, still maintained viscosity similar to new oil and was void of any suspended particulate down to about 2 microns. I run the oil through a very fine "coffee filter" while the oil is hot (other wise it takes a looooong time). The oil filter is good for about 5 microns at best. this stuff is VERY fine. Nothing left on the paper of note so I know the oil was clean in that respect. I would have no issues running it another 3 or 4 k km in the bike if it wasnt for the sticky clutch issue.
I routinely run Synthetic oil to 10,000Km or more and random analysis says its quality at change time is around 70-80% so really not too bad. I dont bother with the analysis anymore since I am familiar with the quality at change time. I am more concerned about metal. Almost 70k on the bike now so I want to keep an eye on it.

[John Hopkins]

If my oil is black I feel I should have changed it earlier...Just the way I feel, usually based on the fear of damage to my engine and the fact that I can afford to buy a gallon of oil any time I want to..

John.

[gat803]

Originally Posted by John Hopkins

If my oil is black I feel I should have changed it earlier...

Depending on the brand, the color of used oil means exactly nothing. Some oils turn dark after the first time they are brought up to operating temperature.

[Scrapdog2grand]

Originally Posted by gat803

Depending on the brand, the color of used oil means exactly nothing. Some oils turn dark after the first time they are brought up to operating temperature.

some oils are dark rite out of the bottle.

[gdb069]

Originally Posted by Scrapdog2grand

some oils are dark rite out of the bottle.

I just put some Royal Purple in a boat transmission. First time I used Royal Purple and thought I was pouring used oil it was so dark. Makes it easy to see on the dipstick though.

[Carl722]

You can't see 5 microns. I do hydraulic fluid contamination analysis on the Navy jet I fly on and you can't see anything that small in the fluid. Visible particles are probably larger than 25 microns.

[cl65ame]

I am aware of that. But a whole lot of 2-5 micron particles make a nice little sludge pile. As I said ALL of the oil is filtered through the fine filter which will leave behind all those "solids" as a nice little pile that is visible. Most of those small particles are carbon and general "dirt" not usually metal.
I do regular hydraulic and oil analysis myself on large transport category aircraft.

[John Hopkins]

Originally Posted by gat803

Depending on the brand, the color of used oil means exactly nothing. Some oils turn dark after the first time they are brought up to operating temperature.

I guess my lack of knowledge has something to do with the fact that I have never used synth or semi synth oils...It took me years to convert from DOS to Windows so I don't think I will be changing from mineral oil anytime soon.

I wouldn't be using unleaded if I could still buy leaded..

John.