yanmar coolant hoses - change to silicone?

[bikedaft]

about 15yr old 3gm30f (fresh water cooled with raw water heat exchanger)

there are two 24mm id hoses that are pretty soft, one straight, one "L" shape" (for coolant) by the water pump, and heat exchanger at front top of engine.

haven't got either off, cos that will destroy them, but they measure at 24mm, can only seem to get 25mm id silicone hoses, i'm guessing that will squeeze down ok with a jubilee clip?

http://www.autosiliconehoses.com/silicone-hose-shop/performance-silicone-hoses.html

of course I could just get yanmar parts, but silicone seems to last forever. maybe I should just get yanmar, cos they should fit?

thanks

 

[jerrytug]

I was planning to go silicone like you, I just can't see why not. Clean up the pipes or stubs they fit over, dip the ends of the hoses in hot water, and use the best quality, wide stainless hose clamps, and surely it's the best job possible. I would love to hear if anyone disagrees and why.

 

[Mel]

I fitted a number of silicone hoses to my 1GM10. One has a tee and that would be very expensive but the straight and elbow types are not so bad on cost. This was done two years back and all remains OK
Your reasoning is similar to my own on long lasting reliability

 

[vyv_cox]

Silicone rubber takes heat very well and is long lasting. It is, though, quite expensive. The original hoses on my 3GM30F are now 12 years old, done 2000 hours, still look like new (although I accept that they may not be internally). That seems like a reasonable life to me, so difficult to justify buying more expensive ones.

 

[Loryma]

about 15yr old 3gm30f (fresh water cooled with raw water heat exchanger)

there are two 24mm id hoses that are pretty soft, one straight, one "L" shape" (for coolant) by the water pump, and heat exchanger at front top of engine.

haven't got either off, cos that will destroy them, but they measure at 24mm, can only seem to get 25mm id silicone hoses, i'm guessing that will squeeze down ok with a jubilee clip?

Silicone Hoses - Shop All

of course I could just get yanmar parts, but silicone seems to last forever. maybe I should just get yanmar, cos they should fit?

thanks

İnside diameter of rubber hose must be 28mm instead of 24mm as per service manuel.

 

[bikedaft]

Thanks! I bought OEM hose but still haven't fitted it... Hmmm. Ta

 

[Laysula]

İnside diameter of rubber hose must be 28mm instead of 24mm as per service manuel.

If the stubs on the engine are 25mm, how do you fit a 28mm i/d hose without it leaking?
Obviously the i/d of the stubs is less than the i/d of a fitted hose so won't restrict the flow.

 

[Halo]

The OEM ones on my 3YM30 have lasted 15 years and benefit from screw in plugs coinciding with low points to make draining and flushing the coolant much less messy. I carry a spare set and a hose repair kit (like self amalg tape and cloth tape) so don’t think it’s worth going to non standard hoses.
I would recommend a small Honeywell water alarm under the sump for early warning of leaks - most likely source being one of the pumps

 

[Loryma]

Thanks! I bought OEM hose but still haven't fitted it... Hmmm. Ta

If the stubs on the engine are 25mm, how do you fit a 28mm i/d hose without it leaking?
Obviously the i/d of the stubs is less than the i/d of a fitted hose so won't restrict the flow.

If the stubs on the engine are 25mm, how do you fit a 28mm i/d hose without it leaking?
Obviously the i/d of the stubs is less than the i/d of a fitted hose so won't restrict the flow.

Since I was planning to replace the fresh water cooling pipes of my 3gm30f engine, I checked the yanmar service manual for the corresponding engine model. Obviously, the diameter and wall thickness of the rubber hose are specified as 38mm and 5mm respectively. I consider to replace the existing hoses with sillicon type for better performance. if any experience and advice I thank in advance.

 

[vyv_cox]

The same hoses that I mentioned in post #4 are still in service, eight years further on. The engine is now 22 years old, very few parts have needed replacement: one set of belts, a water pump and an exhaust elbow.

 

[Laysula]

I read from the original post that the O/d of the pipe studs was 24mm and the o/p could only get 25mm i/d pipe. I assume that the O/P has measured the pipe and stub correctly, so that is what I based my answer on. If I am buying new hoses I would base them on my own measurements. Manuals have been known to be wrong/misprinted and engines have been known to have their spec changed and the manual not updated

 

[Loryma]

Since I was planning to replace the fresh water cooling pipes of my 3gm30f engine, I checked the yanmar service manual for the corresponding engine model. Obviously, the diameter and wall thickness of the rubber hose are specified as 38mm and 5mm respectively. I consider to replace the existing hoses with sillicon type for better performance. if any experience and advice I thank in advance.

today, we replaced the fresh cooling inlet hose with the attached oem hose. You can rest assured that the I/d hose is 28mm and WT 5mm. OEM Part Number, 7705226020

 

[Laysula]

Good to know. Perhaps bikedaft can let us know if he made an error on the measurement of his hoses ?

 

[bikedaft]

when it breaks and i put the new one on... thanks all

 

[Loryma]

today, we replaced the fresh cooling inlet hose with the attached oem hose. You can rest assured that the I/d hose is 28mm and WT 5mm. OEM Part Number, 7705226020

FYI, the hose was not easy to replace as it was melted/weak in bad condition. it takes at least 2 hours and can't be done at sea at all. the rest of the other two hoses will be more difficult as they are not easy to reach. I highly recommend replacing all fresh cooling hose after 12-15 years.

 

[Loryma]

today, we replaced the fresh cooling inlet hose with the attached oem hose. You can rest assured that the I/d hose is 28mm and WT 5mm. OEM Part Number, 7705226020

FYI, the hose was not easy to replace as it was melted/weak in bad condition. it takes at least 2 hours and can't be done at sea at all. the rest of the other two hoses will be more difficult as they are not easy to reach. I highly recommend replacing all fresh cooling hose after 12-15 years.

FYI, the hose was not easy to replace as it was melted/weak in bad condition. it takes at least 2 hours and can't be done at sea at all. the rest of the other two hoses will be more difficult as they are not easy to reach. I highly recommend replacing all fresh cooling hose after 12-15 years.

FYI, the hose was not easy to replace as it was melted/weak in bad condition. it takes at least 2 hours and can't be done at sea at all. the rest of the other two hoses will be more difficult as they are not easy to reach. I highly recommend replacing all fresh cooling hose after 12-15 years.

during the replacement of the fresh water cooling hose, you should also check the thermostat and clean it properly with the appropriate solvent.

 

[Laysula]

Cheers for that. Did you replace your pipe as preventative maintenance or because of failure?. I see you removed the thermostat housing, was this necessary to change the pipe or was it off for another reason?
Steve

 

[Loryma]

Cheers for that. Did you replace your pipe as preventative maintenance or because of failure?. I see you removed the thermostat housing, was this necessary to change the pipe or was it off for another reason?
Steve

Yes, it was for preventive maintenance. I think removing the thermostat for easy / convenient hose replacement is a must. in fact, preventive maintenance should be considered extensively within the closed fresh cooling system against overheating

 

[Laysula]

Cheers.

 

[Laysula]

Just changed all my freshwater hoses for silicon. I used two generic 90 degree bends and a short connector all from auto silicon hoses. I had to cut them all down to size which was pretty easy and all inside diameters were 28mm.