It happened around 7:30 a.m. Tuesday on the southbound side between the Academy Road and Cottman Avenue exits.
Images from Sky6 showed flames engulfing the engine area of a light-colored sedan.
No fire department activity was observed in the area as the fire continued to burn for 20 minutes or more.
The right lanes of southbound I-95 were blocked, causing an extensive traffic backup at the height of the morning rush hour.
There was no immediate word of injuries.