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Big Cam Cummins intermix

14498 Views 9 Replies 4 Participants Last post by  NP
Ok, here goes the dumb question of the day. But, I since I don't know I have to ask. My neighbor has a Big Cam Cummins in an older C/O and it started intermixing oil and water. He had another mechanic friend briefly look at it and advised him on what to do, because he did not have the time to fix it. He said pull the manifolds and see which cylinder is bad, pull the pan, the bad cylinders piston and the cylinder head of the bad cylinder. Then replace all bad gaskets and reassemble. I understand the head removal, but why the piston? I'll probably be doing the work on this engine and don't want to take things apart that don't need to. Thank you in advance for all input.
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You might get lucky.... it might be the head gasket. My two semis have a head of now, seeping to the outside of the block..... but it could go the other direction any time.... :sick::nono:

If you get a head gasket, someone told me to get the head gasket with the oversized O rings for the coolant passages. Something about small cracks around the holes.... been a while since I talked to someone about the old Cummins NTC series.
That was very common with those engines. We used to re-torque the heads all the time. You might give that a try.

A mechanic buddy said that. Said to go drive the thing, get it warm and then retorque the head. A little hard to get it good and warm when it's freezing. I'll wait for spring/summer.
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