So on a 6.4L, as well as many other common rail diesels, the fuel system can pressurize to over 20,000 PSI. The 6.4L has pressures up to 26,000 PSI. The new 6.7L can reach 30,000 PSI. The problem is fuel quality and whether or not the owner/driver knows how to recognize it when it happens. When the fuel pump goes, it destroys EVERYTHING down the line. Injectors, supply lines etc. A fuel system repair starts out at about $6K if caught early. Run it for a second too long runs you $7-9K. Run it for 2 seconds too long, new engine. $10-15K depending if the block is ok. The problem isn't the system. In most failures I've seen, it's the fuel and poor maintenance. Insurance usually pays for it if it is determined to be contaminated fuel. You can also go after the station if you have receipts.