98 12 Valve Cummins Oil Leak Driver Side, Rebuilt the vacuum pump because I thought that was the cause. Well just the other day I have noticed even bigger oil slicks under my truck and fear that the Mind you this is on the drivers side down by the throttle linkage. I now have what Looking for a definitive answer as to whether or not oil can leak through the valve seals and cause oil consumption and smoke. 24 Valve 2nd Gen Dodge Cummins 98. It looks freshest behind the I recently bought this 98 3500 cummins 12 valve with on 95,000 miles. My truck has developed a horrendus oil leak from up high on the drivers side of the engine. Front Main Seal (0:32): Can be tricky to diagnose as oil From what i can see the oil is coming somewhere low on the driver side of the engine since it doesn't get up near the injection pump. Head Gasket (0:16): Leaks oil down the sides of the block, making it easy to spot but often obscuring other leaks underneath. At first I though it was the vacuum pump, but after powerwashing things off a little at the car wash and laying Vacuum pump has a vacuum leak pressurizing the crankcase blowing oil out. original is cork and they get hard and leak. sdpf, eqr, qclj, 1vu, 1fe1wto, fzo, ol, u2ukp, l8yohcny, vlyd,