Thanks to Louis for pointing out that I'd called it a CRV in an earlier post :P

CDR was spotless 10-12K miles ago. Now the bottom half is covered in oily grime. Manometer test shows a 1" delta at idle, about 4" delta at 2000 rpm. Should I wipe it down and let it be or does this mean it needs a new hose or grommet?

Thanks,
Sixto
97 C2500 'burb

How many miles on it (CDR) it is recommended that it be changed every 30,000 miles. It is also recommended that the valve cover o-ring be changed at the same time.