The way I see it, you put it on, drive it and once the warranty expires, know that if it fails, it is just the pump that gets replaced. If it fails while under warranty, you can beat Ford up with the fact that only the pump failed and it did not damage the rest of the fuel system, which saved FORD $8K in warranty coverage. Of course Ford would try to use fuel contamination long before they blamed the DPK.

 

So with the DPK, lets say water, DEF or some other type of contaminant was in the fuel and eventually caused the CP4 to fail. I understand the DPK catches the metal debris from the CP4 innards, but wouldn't that contaminated fuel (water, def, gas, whatever) have already passed through the entire fuel system? Potentially causing rust or contamination throughout.

It seems that the DPK is most beneficial when it's a pump failure not do to fuel contamination. But if it is caused by fuel contamination, which I've heard most are, then you would need the full clean up and fuel contamination kit anyway, DPK or not.

 

Depends on the amount of water or DEF that got in. If DEF gets in, just a small amount can destroy the pump without affecting the injectors. Whatever material the CP4 is made from, it corrodes quickly with DEF and water. The thing is, it takes time for a CP4 failure to spread to the injectors and the rest of the fuel system, so if there was a little amount of water that got in the fuel, it could have been a dozen tanks back, and with a DPK the damage to the pump would be caught between the filter and CP4 and not reach the tank. Eventually the pump fails but during that time from initial failure to full on failure, the rest of the fuel system stays clean.

If you get enough water in the fuel to get to the injectors, that is some really BAD fuel! If you pump DEF into the diesel and drive, well, kiss the fuel system goodbye, even with a DPK.

 

That's my understanding. A DPK will protect your fuel system from the CP4 should it take a dump, but if water or other contamination is in the fuel, it won't stop that from circulating. That's why I choose to use an additive also. I use Hot Shots EDT, which is a water demulsifier. This should completely separate any water from the fuel, which should then settle in the lower filter, and can be drained out at the WIF drain. I know some don't like to (or think they should) drain this unless the warning light actually comes on, but if there is even a little water that remains in the filter, algae can start growing from it, which IMO is a good enough reason to drain at least a little off every so often. The light won't come on until the water reaches a certain level. Of course, things like DEF and gasoline are just going to ruin the system anyway, but thankfully, it is the one thing that we can control if we stop long enough to think when filling up. Besides that, I like a locking fuel cap too... not because it will keep people from stealing my fuel (they can just punch a hole in the plastic tank if they want that) but because it will be an indicator to me that something isn't right. Besides all of this, Hot Shots also claims that they have "rust and corrosion inhibitors" in the EDT additive, along with other beneficial things, such as added cetane and lubrication, as well as cleaners and fuel stabilizers too. I know, it sure does sound like I am bought in, but like I mentioned earlier, I sleep better at night knowing I treat my fuel, and I have a DPK installed. That's about all the added insurance one can have to prevent anything from happening. If it still happens, I have to hope that either Ford does the right thing, or get my insurance company involved.