I agree 100% on the factory limiting valve. The main reason I bought the new spider hose was for the valve. Mine got pushed against the coolant reservoir and cracked. The old spider hose was old and more brittle, but I couldn't find any cracks in the hoses.

Are you saying the catch can might be too restrictive? I guess I'll know if I drain it and nothing comes out. That would show there wasn't enough airflow in the pvc hose to pull oil into the can. It was pulling it before so it should pull the same amount into the can, right?

'00 S4 >> '08 135i.