dirty coolant in 6414DF marine diesel

[schoolsout]

Doubt this is the issue and I don't know how your engine is set up, but have you cleaned the heat exchanger at all? It will build up with mineral deposits, but I've never seen it turn coolant dark, just inhibit its flow.

 

[Labrador Coaster]

The motor uses a ''keel cooler'' which is essentially a closed loop of 1 1/2''copper tubing attached to the outside of the hull, the cold salt water cools the coolant. I will haul out in a week or so,, We were thinking that perhaps there a leak in the pipe and the coolant is mixing with the salt water.

 

[Zebrafive]

I'll bet pressed on for the impeller

 

[jenkinsph]

The motor uses a ''keel cooler'' which is essentially a closed loop of 1 1/2''copper tubing attached to the outside of the hull, the cold salt water cools the coolant. I will haul out in a week or so,, We were thinking that perhaps there a leak in the pipe and the coolant is mixing with the salt water.

If that is the only reason for the haul out I would consider capping and pressure testing the outside loop to determine if I had a leak first.

 

[Labrador Coaster]

Yup, pressed on indeed, I ended up breaking the impeller, stripped one of the threads on the impeller trying to pull it off, I them moved the pullers to the exterior and proceeded to break it in half, I then went on-line and downloaded the shop manual. As the saying goes.. (''Locking the barn door after the horse has been stolen...)

I called a local John Deere dealor for parts, he related the difficulties of pressing on seals, bearings, pulley , impeller etc. I ended up ordering a complete water pump, a JD original part 931.50$ - yikes.

Sad thing is,...I'm not sure that that was my problem, I had a bit of a wobble in the pulley but I didn't see any coolant leaking from the pump.

And yes a pressure test is a good idea, unfortunately our boating season is at an end here, -10 Degrees c, whats that 20 F? forecasted tomorrow. Gonna haul her on the 25th.