with today's low hoodline and lighter cars, manufacturers are using composite materials for some of the engine parts to include the valve cover. there will be more composites in the engine compartment. the radiator which is subjected to pressures up to 18 p.s.i. and heat up to 240 degrees fahrenheit, within five years ( when you have paid for the car already hehehehe), the upper radiator plastic (phenolic) tank begins to develop cracks. one inexpensive way of repairing the crack is by using fibreglas resin bigger than the cracked area. it begins with draining the radiator and cleaning the affected area with commercial grade acetone. then with a disposable brush, apply the resin+hardener mix to the area, then cover with a small fibreglas fabric on the crack, apply the resin mix on top of the fabric. let stand for at least six hours to cure.