Based on my own trip in July 2016, I would suggest, you can certainly take your car to Kalam. However, as others have suggested, you need to be very patient while driving and may need to drive at a speed of 10-15 km/h most of the time.
It should no way take 6 hours. It took me 2.5 hours while going from Bahrain to Kalam and 2 hours while coming back. but I was not as patient as I should have been. At most it will take 3-3.5 hours and your car will inshaAllah have no trouble.
My car was Nissan AD van.