3GM30F Cooling Hose Replacement

[sailcapt340]

I am planning to replace all the cooling water hoses on my 2000 340 (3GM30F). By cooling hose I mean those antifreeze filled hoses.
I thought I would drain the system from the hose cap located at the back of the water heater. It would be the lowest point in the system as far as I can see and the cleanest way to go.
Has anyone done this job and if so any suggestions before I begin? I have the thermostat and gasket and am looking to purchase the hoses next.
Thanks for any help.

 

[BWagner]

Just wondering how many hours you have on your engine?

 

[sailcapt340]

Engine hours

Only 343 hours.

 

[Cool_Change]

We have the same boat and about double those hours. Not saying not a good thing to do but what prompted you? Are you noticing some degradation or purely preventative?

 

[sailcapt340]

Some small signs of fatigue

I am starting to notice some soft spots in the hose in front of the engine. This is a pretty rigid hose so the soft area is what has me concerned. The others are seem fine, they do get soft after the engine has run for a time, but this would be normal. To show a soft spot while cold, that's a whole different thing.

 

[Bob 04 H260]

I did mine on our boat last spring, same engine. I thought at 10 years it is a maintenance procedure. It was also good time to flush it all out and put in new coolant. I kept all the old Yanmar hoses as spares in case of an emergency.

I found one of the hoses going to the hot water tank was rubbing on something under the cabin sole and had a flat spot on it so I was glad I pulled them out and replaced them.

I just drained my coolant into a plastic bottle using the little taps on each side of the engine. It will be a bit of a mess no matter what you do. Anything spilled just ends up up in the sump below the engine and so no worry about being pumped out of the vessel. I just mopped it all up at the end. I also replaced all the raw water hoses, belts and raw water pump impeller, installed a speedseal.

I used a water hose to back flush both the fresh and raw water systems.

Also replaced the mixing elbow at the same time.

I used all ABA hose clamps, with a rolled edge and smooth s/s band and no perforations so they are not as hard on the rubber hoses.

It can take some playing around to bleed all the air out of the freshwater side.

But worth the work in the end for the piece of mind.

good luck, Bob

 

[PGIJon]

Envious of Bob's Engine Access!!!!!!!