CDR defined "borrowed from flashoffroad.com"
The Crankcase Depression Regulator (CDR) Valve
maintains crankcase pressure. Pressure must be regulated to prevent oil consumption through the intake system, and to prevent oil leaks due to excessive buildup of pressure. Control is accomplished by regulating the blow-by gases into the intake system to be reburned. Inside the CDR valve, a spring holds open a valve plate that connects to the CDR valve body with a flexible diaphragm. The valve plate is capable of restricting the outlet passage to the turbocharger air inlet duct when airflow pulls it closed against the force of the spring.
The CDR valve is responsible for controlling the pressure/vacuum in the engine crankcase, and separating the oil mist from the air and returning the oil to the crankcase. When the pressure builds up because the CDR is stuck closed the crankcase pressure will increase, and could force oil past some gaskets and seals that could result in leakage.
If the CDR is stuck open oil mist from the crankcase will be sucked into the engine and burned as fuel, however, it is heavier and thicker than diesel fuel and, having greater BTU output, causes excessive heat in the cylinder. After a period of time, cylinder and head temperatures will reach unacceptably high levels causing the head bolts to stretch and the head gasket to fail.
A quick way to inspect your CDR valve is to remove the air cleaner assembly and look into the air intake with a flashlight. If you see engine oil mist in the intake manifold, test it out per the instruction above or get a new one.
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Crankcase Depression Regulator Valve
Not sure about the pressures as listed, but my guess is anything close is good...
So I guess as long as the spring on the inside still has a decent "spring" to it you could just wash out "carefully" and reinstall....
