Oil question

[87TurboGirl]

We are just kinda of curious on this one but, we just changed my oil about 75 miles ago and had to drop the oil pan to check something out. And my husband noticed the oil is a black as night. Any idea what could cause the oil to turn black so fast.

We use mobile 1 synthetic.

Thanks.

 

[blackbuick87]

You cant judge an oil's cleanliness by its color, it will turn black just sitting there by absorbing humidity from the air. Its similar to how brake fluid changes color over time. Also when you change the oil it doesnt get every drop out of the engine, and any old oil darkens the new stuff.

I just broke in a new cam in my boat. The pan was off and everything was cleaned. Ran the engine for 45 minutes. changed the oil 2 weeks later and it was black.

 

[tom h]

I'm not accustomed to seeing any vehicle's oil turn dark so quickly (75 miles), unless it was done 1/4 mile at a time at full throttle, or car is used for many short trips.

I might have guessed excessive combustion product blow-by, past the cylinder rings.

87TurboGirl , any reason to suspect piston ring seals are less-than-ideal? Have you ever done a cylinder leak-down test ? (using a Tavia tester or equivalent). I feel a leak down test is a better indicator than a compression test.

Recently I have been driving my chevy k-blazer nearly exclusively on short 1-3 mile trips, never really gets good & hot, and the engine oil (mobil-1) looked really vile: black, and a bit "foamy". I'm sure there was a lot of unburned gasoline, moisture, etc, accumulating in the oil. Until my driving habits change, I'm going to make a point of a weekly 10 mile freeway drive @ 65-70mph.