The motorway is closed eastbound, between junction 7 (Altrincham) and junction 6 (Hale), and is expected to stay closed "for some time", said Highways.
Police, fire and ambulance crews are at the scene, where the car caught fire in the roadworks area.
Drivers are being diverted.
Road users are advised to follow the solid triangle diversion symbol on road signs
- Leave M56 at Jct 7 eastbound and follow M56 Jct 7 spur road
- At M56 Jct 7 spur/A556 roundabout, join A56 northbound and follow
- At A56/A560 Jct, turn right onto A560 and follow
- At A560/A5144 Jct, turn right onto A5144 southbound and follow
- At A5144/A538 Jct, turn left onto A538 southbound and follow
- At A538/M56 Jct 6 rbts, take second exit off first (eastern) Rbt to rejoin M56 eastbound at Jct 6.