Toyota builds parts up and then tears them down again.
In order to test the quality of assembly line welding, riveting and bolting, Toyota sub-assemblies like suspensions, fuel tanks and body parts are randomly selected to be torn apart with an air chisel. This process checks the strength of welded parts, the security of bolted components and the integrity of riveted steel. If the air chisel doesn't reveal a weakness, then years of driving shouldn't, either.
Engine parts are spot-checked for a tight fit.
As engine components move down the assembly line, certain parts will be randomly pulled off the line and measured for variations in size. In some cases, Toyota is checking for variations that are much smaller than the diameter of a human hair. This quality control procedure helps to ensure that critical engine parts are machined to very strict specifications. If the selected part is slightly smaller or larger than the one that came before it, the entire batch of parts is purged from the line and the machine that makes them is adjusted for accuracy.
Toyota engines must survive 200,000 trips to the redline.
One of Toyota's most rigorous engine tests takes randomly selected engines and revs them from idle to 6000 rpm 200,000 times. A car would have to make 50,000 full-throttle runs up a freeway on-ramp or spend 10 years at the hands of a taxi driver to repeat such a torturous process. Although most drivers would never subject their own car to such stress, Toyota knows that a tough engine is a more reliable engine.
Toyota puts the pedal-to-the-metal when testing engines
Toyota randomly selects completed engines and subjects them to 180 hours of full-throttle operation. This test is equivalent to driving a vehicle at maximum speed for 7.5 days-non-stop. The test checks the strength and durability of parts like the crankshaft, bearings, connecting rods, pistons, valves and camshafts. If the engine can survive 180 hours of high-rpm abuse, then years of commuting will seem like a walk in the park.
Toyota pistons are X-rayed for accuracy.
The pistons in a Toyota engine are covered with an anti-friction coating that helps them glide up and down smoothly inside the cylinder. However, this coating must be evenly applied to help ensure longer engine life and smoother performance. That's why Toyota randomly checks pistons to make sure they have a precise layer of the protective covering. And the method for checking the uniform thickness of the low-friction coating? A close inspection with an X-ray machine.