I saw trucks and cars shoot smoke, it wasn't there before. Maybe we can make it so truck shoot more smoke than cars? Give the smoke a better life time so it remains "in the air" for longer? nice to see this tho!
It's part of the new engine thermals. Redline the engine long enough and it will eventually conk out. If you want to speed it up get the drag moonhawk or barstow and change the radiator to the standard one.
It's very enjoyable driving with a damaged truck which has a head gasket failed and water temperature above 240 degrees. It's now converted into a steam locomotive. Big thumbs up from me on this achivement