Questions about a water pump on a d2

Sounds like Rome is right. Time to take it apart again and pull the impeller off to inspect.

Either ceramic seat is damaged, broken loose or its completely missing and the carbon seal and bellows doesn't have enough travel to contact the bare impeller surface. Usual solution is to buy a new impeller and install. I have a cheaper alternative in the works that I need to get back to now that harvest is done.

Another possibility is some of the aftermarket seals I have do not have the carbon ring bonded to the bellows like I expected to see. Not sure how well that is going to seal with it relying on only spring pressure to seal that rubber to carbon joint. I haven't run any if those new seals yet, just installed one in a spare pump I built for a D6 9U.

I have also reattached loose ceramic seats with epoxy as long as they were undamaged.

Ray I had the same fight with a Cat 318 in a D6. Turns out the seals under the pre combustion chambers are leaking compression gases into the water jacket in the head building more pressure than the seal can handle.


Since you replaced seal and bearings in pump,when does it leak? If only after warming up it is most likely the pre combustion chambers. I had the book and did it as it says twice. Took a good pump off a running engine and it leaked too. So watch the top of the radiator for air bubbles and foaming as start working and bring it up to operating temperature.

I have several D6's the one giving water pump problems is not my favorite and is back up at this point. So I put block sealer stop leak in when it is time for more anti freeze.


I have had other battles with the pre combustion chambers on Cat 318 engines. Back in the day the seal was a copper washer. Today Cat and after market seals have all been a steel washer with copper spray. My machinist for head work did not want build tooling to dress the seats. But did find copper washers from McMaster-Carr industrial supplies that worked on one.


There is a thread on the board about building tooling and dressing the precup seats,if the softer more compressible washer will not fix you head.