6.9L & 7.3L IDI CDR Valve Replacement

How to Replace the CDR Valve on the 6.9L & 7.3L IDI Diesel

The crankcase depression regulator valve (CDR) on the 6.9L/7.3L IDI diesel is used to regulate pressure within the crankcase as well as prevent engine oil from entering the intake. The CDR is a serviceable part, meaning that it can removed and cleaned. If there is visible oil on the air cleaner stud or in the intake manifold, then the CDR valve needs to be cleaned or replaced. Failure to service/replace the CDR as necessary increases the risk of a head gasket failure, as the engine will be drawing motor oil into the cylinders and burning it. A plume of gray smoke upon starting may also be a sign that the engine is burning oil due to a faulty CDR valve.

Applicable Model Years: 1983 - 1994 6.9/7.3 IDI diesel (naturally aspirated)
6.9/7.3 IDI CDR Valve: Ford part # E3TZ-6A665-A (International part # 1805319C1)
CDR Valve Gasket: Ford part # E3TZ-6A892-A
Note - Ford lists the CDR valve as an "Adapter". The gasket is sold separately.

 

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CDR valve location on IDI diesel

• Remove the air cleaner and you will see the CDR valve attached to the back of the intake manifold.

• The image at left shows what the CDR valve looks like and how it attaches to the manifold. We happened to have a spare laying around, you won't need to remove the entire intake to get to the CDR valve.

 

CDR valve removal

• Use a 1/2" socket to remove the two bolts that secure the CDR to the intake manifold (red arrows in photo). Be careful not to drop any tools or hardware into the engine valley, as fishing it out won't be fun.

• Pull the CDR valve slightly towards the firewall and then pull upwards as you wiggle it side-to-side. It should come out with little effort.

 

Assembling replacement CDR valve

• There's no reason why you shouldn't be able to reuse the tube that connects the CDR to the crankcase. Remove it, clean it, and install a new o-ring onto the replacement CDR before attaching the tube.

• Install the seal that seats betweens the CDR valve and intake manifold, coating it with a light film of fresh motor oil.

• From here, replacement is reverse. Make sure that the CDR valve tube seats properly and that the CDR seal is aligned properly when reinstalling.

 

Bad CDR valve example

• In the photo to the left, you can see oil pooling up in the CDR valve after removal. This is a good sign that this valve has been allowing excessive engine oil from the crankcase to pass through the intake manifold.

• An alternative to replacing the CDR valve is to lightly clean it with a solvent. Do not allow any solvent to come in contact with the valves seal/o-ring, as it may damage it.