The vehicle, which was travelling in lane one on the northbound carriageway between junctions one for West Bromwich and two for Oldbury, burst into flames about 4.30pm.
Three fire crews were immediately dispatched to the scene and the fire was quickly extinguished.
However Highways England had to shut off the entire northbound carriageway with traffic queuing as far back as Frankley Services near Junction 3 for Lydiate Ash, Bromsgrove.
#WestMidlands We've temporarily halted traffic, #M5 n/bound J2 - J1. A car has caught fire within the roadworks. @WestMidsFire are on-scene. Expect delays. Approx' 6 miles of queuing traffic, back to #Frankley services near J3. @CMPG @motoway pic.twitter.com/U5RsXlp78X— Highways England (@HighwaysWMIDS) November 16, 2017
It was re-opened about 5pm but delays continue.
Drivers are advised to avoid the area.