
Sources connected with the show tell TMZ, a production assistant was driving the car -- which belongs to Richard aka "The Old Man" -- and right before he made it back to the shop for yesterday's taping ... the engine suddenly burst into flames.
They haven't pinpointed the exact reason behind the miniature explosion -- but we're told, a loose fuel hose is probably to blame.
No word on the extent of the damage either -- but according to our source, it shouldn't be too hard to fix.













