Solidified engine oil - GIF

[Elizabeth Greene]

A few things.

This was probably coolant in the oil. It's still slimy and semi-liquid, but that muddy chocolate texture is what that looks like. If you're a mechanic and have never seen this, I'd question how long you've been doing it. You see this from head gasket failures or intake manifold gasket failures on occasion. You also see it to a lesser extent if some genius leaves your drain pan out on the driveway and it gets rained in. :/

A related cool thing is if you put windshield wiper fluid in the oil. It solidifies it like Jell-O. Not liquid at all; you smack it and it just jiggles.

For a car that goes a long LONG time without an oil change you just get *black* sludge. The detergents finally give up in the oil and the muck just gloops onto everything. As long as the hydraulic lifters aren't completely gummed up you can usually bring these back to life.

On the cash-for-clunkers thing. That happened in 2009; you can see the impact on used car prices in the BLS data.