i just had my motor rebuilt. I have changed the oil 3 times in about four thousand miles. First two times were in one thousand miles increments. Oil looked great when drained both times. This last oil change had about 2200 miles on it.
I pulled the drain plug out and i noticed it not flowing as fast as it used to. When it gets down to the bottom of the pan clumps of oil are coming out. It was really black and clotted together. When i poured the filter out i could barely get the sludge in there to flow out. The oil looked like the consistency of applesauce. Not milky at all.
The block was a cracked head worn out block. The lifter bores are still more then likely worn out. It gets a light tap to it after long drives. Sounds lifter like. Still dont have super oil pressure, but in spec.
I used pensoil once during the break in with a zinc additive. There has been two castrol 10w30 changes before today.
The things i have read say that when oil looks like that its because its really old and abused. But, its rebuilt motor with all new internals beside rods and turned crank. The oil had also only been in there for 2200 miles.

 

Who did the rebuild?

 

A local machine shop did the machine work and assembled the engine.

 

I'd tend to want to send in a sample of that "lumpy oil" to a lab for analysis.

I use and highly recommend Blackstone Labs. Link below. They will send you a test kit free for you to send a sample into their labs. Prices are reasonable. Oil analysis will tell you a lot and they turn your sample quickly........it sure beats guessing.

http://www.blackstone-labs.com/

 

This is going to be the best idea. Instead of a pile of internet goofs throwing crap out there... let actual science do its thing.

 

Oil analysis is the way to go. Way better than guessing