AAAAWWWWWWwwwwwwwwwwwwwww jimminy crickets, I wish you hadn't said that...

Yup, it is possible that heating a motor would make it easier to start. Depending on the type model motor, it might actually make it harder to start. Honest.

Having flown in Minnesnowta when it was below zero (I'd tell you how much below except I could never get myself to look at the thermometer.)...................

When it's so cold the residual in the engine thickens and makes the suckers hard to turn over, sticking the engine directly into your car's exhaust is one thing to do. I never used my buddy's Minnesnowta beater (a special kind of car usually only seen in the dead of winter) exhaust however. Lord knows what acids and caustics were in that smoke.

I wasn't worried about catching the plane on fire or burning my hand. More worried what my hand would look like the next day. And my jacket sleeve. And my watch. And my blood chemistry from what would be absorbed.