What is the DOHC oil restrictor?
Under hard use (over 6000 rpm), the DOHC engine generates enough vacuum to inhale oil through the crankase ventilation system. The oil restrictor is a small insert that goes in the return air line that comes out of the driver’s side of the valve cover. The restrictor limits the amount of airflow and prevents oil from entering the air intake system. This piece (p/n 4856291) is available over the parts counter for about $4.00. This problem was described in TSB #09-07-95, which specifically mentions ACRs. However, any hard-driven DOHC should have this piece installed. The symptom that indicates this problem is smoking through the exhaust, particularly following a long, high-RPM, right-hand turn. 2.5.
Under hard use (over 6000 rpm), the DOHC engine generates enough vacuum to inhale oil through the crankase ventilation system. The oil restrictor is a small insert that goes in the return air line that comes out of the driver’s side of the valve cover. The restrictor limits the amount of airflow and prevents oil from entering the air intake system. This piece (p/n 4856291) is available over the parts counter for about $4.00. This problem was described in TSB #09-07-95, which specifically mentions ACRs. However, any hard-driven DOHC should have this piece installed. The symptom that indicates this problem is smoking through the exhaust, particularly following a long, high-RPM, right-hand turn.
