Don't ask me where I got this bad EGR from a 2006 CRD with 3000 miles. All I can say is that I spent A LOT of time bartering.
The EGR can be broken down into two parts, the solenoid on the right and the EGR valve on the left.
The EGR on the CRD is an electrically controlled EGR. There is some mis-information out there that the EGR is vaccum operated and modifying the exhaust will void the warranty. That’s pure horse hockey!
There are two small coolant pipes for coolant in and coolant out, which cool the two mated surfaces between the solenoid and EGR. The solenoid would get burned up in a hurry if that coolant jacked did not act as a heat sink.
This is yet another load on the coolant system along with the engine and transmission cooling needs. It’s imperative to have a good operating cooling system. Make sure that you take good care of doing your radiator flush and fills each year.
Rotational View.
This shows the inlet for the exhaust gases to come in.
Rotational view.
This shows the cavity where the cooled exhaust gases mix with the CAC (Fresh Air) coming from the output of the intercooler and passing through the EGR Flow Control Valve
Rotational view.
Rotational view
The solenoid is on the left and the EGR valve is on the right. Notice how the surfaces mate with each other. The solenoid basically either pushes or retracts the pintle against the seat of the EGR which causes the EGR valve to open.
Also, notice that the solenoid can "sense" if the EGR valve is closed because the seat of the outer ring EGR contact plate will seat flush against the solenoid.
This is another closeup showing the solenoid and the pintle.
This shows that without a current applied to the solenoid, I can use a pencil to push it down. It acts similarly to a dead bolt on a door. It's either retracted (pulled in ) or extended (pushed out). If the pintle is pushed out under a current applied to the solenoid, forget using a pencil to move it.
This is a close up of the EGR surface that mates to the solenoid. Notice that there is a stripe on the left of the surface. This could be a leak from the coolant jacket.
This is a side view of the EGR there are two diaphram disc valves on each side of the spindle. If the EGR is closed then no gases are in the cavity. This cavity is where the CAC air (Fresh Air) comes from the intercooler and is controlled by the EGR Flow Control Valve. The Flow Control Valve is not pictured.
Another view of the EGR where you may see the disc valve barely.
This is where the exhaust gases enter to be recirculated in the previous picture
To push the EGR Valves in the open position, takes quite a bit of pressure by the pintle from the solenoid. I'm using a screw driver here to show that the spring always holds the valves shut so that no exhaust gases enter.
I really had to push HARD with my thumb on the EGR plate to force the diaphram discs to open up. You'll notice that this opens the valve for the exhaust gases to come into the larger EGR cavity to be mixed with the fresh air. The exhaust gases them mix with the CAC (Fresh Air).
This shows that the cooled exhaust gases are now let into the EGR cavity to next be mixed with the CAC (Fresh Air) and then be pushed into the intake.
I'm sure these photos will stir much discussion, which I hope they do.
The failure points for the EGR as far as I can tell are the following:
1) The solenoid fails and does not operate the pintle in and out.
2) The Coolant Jacket fails and leaks
3) The EGR diaphragm valves get stuck and the solenoid cannot operate
Keep in mind that the EGR pictured above and the EGR Flow Control Valve will throw the same CEL value. Many times the techs will replace both but the flow control valve is much easier to remove and replace. It can be done from topside quickly. Therefore under warranty the tech will do that quickly as it pays better.
Removing the EGR is not a quick component swap.