I've sampled crankcase gases with a 4-gas exhaust analyzer. Lots of CO2, and some unburned hydrocarbons, mostly. Very little carbon monoxide, and just about "normal atmosphere" O2 levels. I've also used an exhaust anaalyzer to test the vapors in a cooling system for CO and hydrocarbons, looking for head gasket leaks. Just be VERY careful not to suck up coolant into the tailpipe probe when you hold it over the radiator cap opening- - - -it severely damages the sensors in the machine if you do!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!