Greetings:

It's winter here in Tennessee a question for the group: If I took a
flexible Aluminim duct,/ hose hooked it up to my car exhaust pipe,
then put the other end in the lower end of the engine cowling to pre-
heat the aircraft's engine would this cause any problems?

I would drill a small hole in the cars exhaust pipe to allow for
exhaust water to escape

Today's cars are very clean burning with almost zero emissions or so
they say? I would not direct the exhaust at the airframe or the
engine just enough to enter the cowling at the nose strut. I would
open the oil door to allow a flow of exhaust. I would leave the cabin
door open on the aircraft to make sure no CO2 besides, my aircraft
has a CO2 detector installed.

I would allow the exhaust to heat the engine up just enough to get it
past freezing give or take plus turn the prop to limber the oil

This seems like a inexpensive idea to pre heat

Any corrosion potential ?? What do you think

Thank you for your comments.