Definition of quantal. 1  1 [Latin quanti how many, plural of quantus] : of, relating to, or having only two experimental alternatives (such as dead or alive, all or none) 2  2 [quantum] : of or relating to a quantum.
3. Engine movement. Another symptom of bad or failing engine mounts is an engine that moves in the engine bay. If the engine mounts are in good condition, they should be able to secure the engine firmly in the engine bay.
Now, when a wheel bearing starts to go bad, they will usually make a howling or whining noise until they finally fail. When they do fully fail they can cause the race to weld to the bearing surface, grind up, and the wheel can fall off the car.