2001 Dodge Durango 5.9L John Sinopoli Sinopolis Service Station
Vehicle: 1994 - 2001 Dodge Ram 1500 Pickup 3.9L
1994 - 2001 Dodge Ram 1500 Pickup 5.2L
1994 - 2003 Dodge Ram 1500 Pickup 5.9L
Symptom: Oil consumption, spark knock, high idle speed.
System: Emissions/PCM/Fuel, Engine Mechanical
Codes: Possible P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 on OBD II vehicles
Problem: The gasket for the bottom plate of the intake plenum is leaking allowing the engine to suck air and oil from the crankcase.
Test & Fix: Testing for crankcase vacuum leaks is a little more of a challenge than external vacuum leaks. There are two ways that work pretty good. The first way is to remove the dipstick and place the hose of a vacuum/pressure gauge over the dipstick tube. Remove the crankcase breather hose and the PCV valve from the valve covers. Block off the crankcase breather hole in the valve cover. Start the engine and raise the engine speed to about 1000 RPM. Monitor the vacuum/pressure gauge as the hole in the valve cover for the PCV valve is slowly blocked off. It should show pressure because of blow-by gases past the piston rings. Do not allow pressure to build up in the crankcase. If it is showing vacuum, there is a leaking gasket on the steel plate on the bottom side of the intake manifold. The second and much easier way is to remove the air cleaner assembly and open the throttle wide open (with engine off) and peer down the throttle body bore using a flashlight. Check for oil pooling in the intake plenum. If oil is found, it also indicates a leaking gasket on the bottom side of the intake manifold. Remove the intake manifold. Remove the steel plate on the bottom of the intake manifold and replace the gasket. Reassemble. It is also recommended to de-carbon the combustion chambers using a suitable cleaner product since the oil consumption has probably built up some carbon deposits in the affected cylinders. A related document, TSB 09-05-00, is available.