Driver John Bach said he had just passed through the intersection of M-104 and Jackson Street at about 8:20 p.m., when he turned to his passenger, Jeremy Caudill, and asked him if he smelled smoke.
Within seconds the two saw smoke coming from the engine compartment and pulled over in the westbound outside lane in front of Arby's and Wesco.
They used their fire extinguisher and another supplied by someone from a nearby store to slow down the flames slightly before firefighters arrived.
"We slowed it up a little bit, but as soon as that oil caught, it really took off," Caudill said.
Spring Lake Township firefighters reported the engine compartment fully involved when they arrived on the scene. Flames worked their way into the cab, but were doused within a few minutes.
A tow truck pulled the semi-tractor away from the trailer and around the corner.
Caudill said another semi-tractor was on the way. They would hook it up to the container and continue to Indiana yet this evening.