If you've blown a ring and are trying to locate the source of your problem, here are some helpful tips that might get you to the source quicker.
A) Problem Starting the Truck: If you're having trouble starting the truck or the truck doesn't start at all this could be associated with the fuel injectors. A leaking injector ring could be the cause of this problem, unfortunately this could also be attributed to a faulty oil pump or multitude of other issues, but a leaking o-ring would be a great place to check first.
B) Simple Deterioration: If you are experiencing a rough idle or loss of power this could be due to deteriorating injector o-rings. These symptoms are usually diagnosed as being caused by using the wrong oil type, however deteriorating rings are an often overlooked item.
C) Fuel Injector Replacement: O-rings are often damaged during the replacement or removal of fuel injectors. Typically, you have to push the o-rings through a pretty tight space to get the fuel injector into the fuel rail. This can often damage the rings if you're not careful. Lubricating o-rings and other parts before any installations will help prevent damage and make the install go quite a bit smoother.
D) Heat Damage: The overheating of diesel engines can cause severe damage to O-rings. When superheated the rings can expand beyond their maximum capacity causing permanent distortion and damage and consequently gaps which will cause leaks. This is most common with injector rings.
E) Oil Leak: A common problem in the 7.3L Ford Powerstroke is developing an oil leak related to the HPOP. This can sometimes look like a fuel leak related to the fuel bowl, but if after changing out the o-rings on the fuel bowl the leak continues, it is definitely the HPOP.
F) Parts are Getting Old: As with all of us, age takes it's toll. Over time O-rings will simply harden losing their ability to expand and contract. They will begin to crack and lose the ability to create an effective seal. If you see a leak at or near the fuel rail connection this is almost certainly an O-ring failure. Sadly, I've been caught in a situation where I've had to run around town hoping that a dealer would have the part I need.
I like to avoid inconvenient situations when at all possible. It might be presumptuous, but I thought some of you might like to avoid the inconvenience of running around town looking for replacement parts and then paying a premium when you find them. There are o-rings for a wide array of fuel and oil related applications on Ford trucks, and because they tend to be a common maintenance issue, I have put together a kit that any Ford diesel enthusiast should own. As I mentioned previously, eventually, your 7.3L Powerstroke will develop a fuel or oil leak. It's only a matter of when.