Originally Posted by arydant

Thank you for that o4fire.

As a result, I did some more digging and found out that "Sludge" can refer to two different things:

"Oil sludge" and "Cold water sludge"

Oil sludge is a tar like substance that forms when the oil breaks down. This is more indicative of failing to change oil when needed and forms throughout the engine.

Cold water sludge is a brownish creamy substance that forms commonly as a result of moisture condensing under the oil cap due to short trips and cold weather. This tends to accumulate under the cap because the filler cap is plastic and colder than the rest of the engine. Moisture mixes with oil to form a residue. The oil, however remains normal.

Most people, as I somewhat mistakenly did, seem to call this "sludge" and that can be somewhat misleading.

As you say, this apparently is not serious and pretty common and can be burned off with higher engine temps.

Thank you all for your help.