Pump Leak

[Norm Harris]

I've got a Palmer P-60 gas engine, with a coolant leak that I don't understand. There is a Jabsco sea water pump that circulates the sea water that cools the engine coolant. Simple enough. As I understand the process, the sea water is piped through a jacket that encloses part of the engine coolant circulating plumbing. (Excuse me if I am unsure of the terminology, plumbing is not my top sport.) Then the sea water is exhausted and cold sea water flows in in a continous process.

I've had some minor problems with the sea water pump, and am planning to take it apart and replace the gaskets and whatever else needs replacing. The part that is causing my befuddlement is that there is a leak from the salt water pump into the bilge, and it is leaking engine coolant. Ya know, the yellow stuff. I can't figure out why there would engine coolant circulating through the sea water pump, unless there is a leak inside the cooling jacket or I don't understand the plumbing.

I'm praying that I don't understand the plumbing!

Any help or advice will be greatly appreciated.

[ 10-27-2003, 07:50 PM: Message edited by: Norm Harris ]

[Bob Smalser]

Raw water is pumped from a seacock to a heat exchanger...a soldered copper (or brazed SS in some, I believe) finned radiator like in an older car.... where it cools the engine coolant.

If you have an antifreeze leak that's not coming from anywhere on the outside of the engine like the waterpump shaft or the headgasket...then you likely have a leak somewhere in the heat exchanger tubing...probably a corroded solder joint.

You could try a can of radiator Stopleak (NAPA) in the engine coolant providing there's no seawater in the coolant (it will be overfull - pls don't taste it)...glorified oatmeal that might plug the leak but reduces the efficiency of the radiator...or the preferred solution is to pull the heat exchanger and take it to a radiator shop for repair.

[ 10-27-2003, 08:57 PM: Message edited by: Bob Smalser ]

[Peter Malcolm Jardine]

When you rebuild your raw water pump, take a good hard look at it. Usually, when the seals go, the shaft is scored and needs replacement, as well as the seals, impeller, and gaskets..(yep, everything but the housing is junk). If any of it looks questionable, REPLACE IT. Losing a cooling pump can be a serious safety problem, sail or power, and cost lots in engine rebuilds.

The heat exchanger in your engine probably has a series of tubes that are encased in a outer jacket. If coolant is starting to leak into it, then REPLACE OR REPAIR IT. Don't use any automotive goop. It will compromise the cooling part of the exchanger substantively, and not guarantee that the problem is gone. Salt water rots an exchanger. If there is one leak, there's more on the way.

[Norm Harris]

Arrrgh!
Of course I was hoping for an early visit from Santa Claus, or a winning lottery ticket.

Thanks guys, I was anticipating your answer and I appreciate your advice. I think that I will replace the heat exchanger. It seems the better part of valor.

Norm

[Bob Smalser]

Yup...best course.

Goop works OK in that crawler whose radiator was holed by a stump...twist shut the broken tubes first....but those machines generally have lots of spare cooling capacity...and boats are almost as bad as airplanes...you only get one chance.