Troubleshoot filty intake plenum

[bshupe]

I have had this 1031 for a couple of weeks and have been working through the basics making sure that the regular maintenance is up to date etc. One of the things I was doing was putting a fresh air filter in and when I pulled the cover to take the old one out I was pretty shocked at how nasty the plenum looked. (photo) The lines on the sides look like they were made by liquid running down the sides, possibly ether although I have not had any problems with it starting since I have had it.

Does anyone have any thoughts on what might be causing this and/or what a good solution would be?

I have seen this on gas engines before when there was excess crankcase pressure or a missing/failed PCV allowing blow-by to foul the intake but this has no such opportunities for that kind of problem.

Thanks in advance!

 

[Cucvnut]

looks pretty normal. could be from the CDR vavle needing a cleaning.

 

[jdeoliveira74]

pretty sure mine looked like THAT too before I change my intake havent checked it since. But I know I am getting some oil thru the cdr, I replaced mine when I got the truck and it was full of oil! Don't know if its normal but it doesn't seem to affect the way my truck runs

 

[doghead]

allowing blow-by to foul the intake but this has no such opportunities for that kind of problem.

You answered your own question!

The CDR valve maintains crankcase pressure. (opposite of a PCV valve!).

Your intake is "normal"


Found on "the internet"

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.

 

[chevyCUCV]

Looks like the 4 intakes i have ever seen