Lost a cylinder head gasket on a 2007 Cummins doing a simple oil change

Two weeks ago I was doing a routine oil change on a 2007 Cummins ISX in my shop here near Louisville. Everything was going fine until I saw coolant mixing in with the oil I drained. That told me right away the head gasket was blown. I had put maybe 500 miles on that engine after a rebuild last fall. I pulled the head off and found a crack in the cylinder wall near the number 4 piston. Had to order a whole new block from a salvage yard down in Nashville. Ended up costing me around $3,200 and three full days of labor. Has anyone else run into a cracked wall on a rebuild that seemed solid at first?

2 comments

2 Comments

samreed1h ago

@quinn341's buddy went down the same rabbit hole I did. What a lot of people miss is checking the block deck surface with a straightedge before bolting the head back on, even on a fresh rebuild. That little bit of warp or a hairline crack can hide until the engine heats up and lets go.

quinn3411h ago

Had a buddy with the SAME issue on his ISX after a rebuild. He found the crack after chasing a mysterious coolant leak for weeks and ended up swapping the whole long block.

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