For those of you unlucky enough to be out of warranty on your 6.7 Powerstroke diesel engine, which is a growing number every day, this is a guide on changing the EGR Cooler core to fix the diagnostic trouble code P0401. The replacement of the EGR cooler core is called upon in a technical service bulletin released by Ford.
Ford wanted to solve some common problems of the past with this engine. Past engines would constantly deposit so much carbon on the EGR valves and it would stick them shut. This happens because the exhaust gas gets cooled through the cooler and deposits on the colder EGR valve. Ford's fix was to move the EGR valve to the hot side of the system.
The exhaust gases enter the valve first then pass through the coolers before entering the intake system so now carbon deposits on the cooler itself.
I do want to point out that this may be an opportune time to install the EGR Delete kit on your drag strip only Ford SuperDuty. The topic of installing EGR delete kits has been discussed endlessly. It is illegal to eliminate or circumvent emissions controlling components installed by the factory on your vehicle, thus only for off-road or racing use. Removing the EGR system will allow the vehicle to operate in a manner of which it was not intended. Eliminating it will require the use of a tuner to fool the truck into thinking it is still attached and working properly. Keep in mind that EGR functionality helps quiet the engine. A good read on the Worth of EGR Deletes.
Flow through the EGR Cooler can easily be checked with an appropriate scan tool. By monitoring key pids you can determine the effectiveness of the cooler. Monitor MAF, EGR Temp, Bypass valve command, and EGR valve command. Set engine RPM to 1200, command the EGR closed and the bypass off. Slowly open the EGR with the scan tool and watch as MAF decreases significantly and proportionally if the cooler is flowing well. The EGR temp will rise so command the bypass valve on. The EGR temp should drop drastically in about 5 seconds if working properly.
Of course, the easiest way to tell if its clogged up is to remove it and see if it resembles the picture at the top of the article. You can see the full size image of that plugged 6.7L Clogged EGR Core.
This is not the easiest thing to replace, but don't be scared because it's not that big of a project. I'll describe to you the way I go about replacing it that also will save you time over the regular standard labor time. Be sure to perform this work in a well lit, clean environment with an ample space set aside for disassembling the cooler after removal. Make sure you have all the tools specifically mentioned in my guide or a comparable equivalent along with drain pans for the coolant. Round up all the parts you will need to complete this task.
EGR Cooler Core - BC3Z-9V425-A
Gasket Kit - BC3Z-9P455-A
Motorcraft Orange Coolant