Cooling water hose in Yanmar 3GMF

[BGR]

I have been replacing the cooling water hoses in my Hunter 34 (1985) Yanmar 3GMF. The last one I need to replace is the hose from the fresh water pump to the heat exchanger (see pictures attached).

Does anyone know if fitting the new hose WITHOUT removing the fresh water pump is feasible?

Thanks!
Bertrand

 

[Gunni]

Bertrand; Believe you only need to remove the thermostat housing to get that hose off and on. Not the water pump.

 

[Allan12210]

You can just pull the thermostat housing off with the two downward facing bolts.

Edit...Gunni beat me to it.

 

[BGR]

Thanks to both for the quick response!
And I guess that without removing the thermostat housing it would be impossible to fit the new hose , right?

 

[Allan12210]

You could remove the exhaust manifold and heat exchanger. That would get it done, especially if you are into self punishment.

 

[Gunni]

...or you could leave the hose in place under the assumption it ain't broke

 

[shavdog]

It looks to me like there is enough room not to remove anything.....I'd attempt that first...and if you end up taking the thermostat housing off I probably would replace the gasket and thermostat

 

[BGR]

Thanks! Yes, I was hoping for not having to remove anything. But wanted to check if anyone had found there is enough room to do that. The current hose doesn't look that bad... and I don't want to start doing unnecessary dissembling. As Gunni suggests, if it ain't broke, don't fix it

 

[Ilanortho]

I just did this job.
Tried to pull off the old hose without removing the thermostat housing and was impossible even after cross cutting the hose. And, there is no way to get the new hose on without taking the thermostat housing off!

Taking the thermostat housing off was easy, but make sure you have a new gasket (or two) available. Spent an hour scraping and dissolving the old gasket off. Took the opportunity to replace the thermostat since the housing was off; is cheap enough and kept the old one as emergency spare (get a spare gasket as well).

 

[BGR]

That is precisely what I wanted to know! Many thanks!!

 

[Ilanortho]

BTW; I was happy I replaced it. I did consider leaving well enough alone after replacing all the other hoses. But judging by the paint flaking off and other lack of maintenance by the previous owner, it left the Yanmar factory on the engine 30 years ago. The clincher was the thought of being stuck out on frigid Lake Michigan because of the stupidity of a situation involving 5 inches of failed hose. It was weak when I cut it cross-wise, and the amount of crud on both pipe ends was amazing. I had to cut it length-wise to un-peel and scrape it off the pipes.

 

[nfg2u]

I would flush the fresh water system and service the heat exchanger and replace your antifreeze. If there is crud on the pipe ends you can bet that the heat exchanger is not in good shape. Get an infrared heat gun and keep an eye on the engine. It's a bit of work but not a hard job, worth doing if you want to keep the engine going. You can take the heat exchanger to a shop and have them clean it and re-install.

Yanmar 3GM30F Maintenance Schedule:
https://docs.google.com/spreadsheets/d/1ilwAYg-aENK0okvtSsxxAH_6-H7hHmsj4GoTv6MV-9o/edit?usp=sharing

 

[Ilanortho]

Thanks, good advice
Ilan