The tanker was entering the 405 from the Normandie Avenue on-ramp shortly before 1 a.m. when it crashed.
It ended up on its side in the slow lane with 20 tons of asphalt all over the road.
The California Highway Patrol says the driver may have been trying to avoid a car in its path.
No one was seriously hurt.
Lanes were shut down near the crash site but all roads have since reopened.