CDR Valve - Diesel Forum

jd2003_03 · 11-17-2012, 01:43 PM

I am trouble shooting my 03' 7.3 FX4 Lariat, it is shaking more than normal when it idles, also i looked at my (just a month old air filter) and there is oil on the filter, so after looking and a few calls to my buddy he said to check the CDR valve but i can't find anything on a 99 and up having a CDR valve. i am stuck and need some help.

ReefBlue · 11-17-2012, 02:57 PM

You would have to ask him what CDR stands for to figure out what he is even talking about.

jd2003_03 · 11-17-2012, 03:09 PM

i know what the CDR valve is, for those that dont know it is the crankcase depression relief valve which is similar to the PCV on a gas motor

**klhansen** · 11-17-2012, 04:03 PM

Your 7.3L doesn't have a CDR valve. The crankcase is vented directly into the turbo intake from the driver's side valve cover. The doghouse on top of the VC has some baffles in it. That's it.

If you're getting a ton of oil in the intake system, you may have a problem with blowby. You can do a check on that with a special tool that goes on the oil fill spout and a manometer to measure the crankcase pressure (with the CCV blocked off).