
Originally Posted by
NZ ECO1
I agree with "please wash me" that heat may be a factor but it would be a distant 2nd to vibrations through the car from bumps in the road. One decent bump can be enough to set the crack off beyond the parameters of a safe repair.
Last time I had a crack repaired the repairer gave me a sheet of circular stickers that could be placed over the chip/crack to reduce the chance of the damage becoming worse. I don't know if or how well they work because I haven't had another crack since I got them.