Yanmar KM4A transmission cooler - needed in northern waters?

[chrismoore58]

Hi all,

I'm new to the forum. I have a 1997 Beneteau 383 (Moorings version of Oceanis 381). The boat used to be in charter in the BVI, but it has been living in quiet retirement for a few years on Lake Ontario. Late last year, the transmission (Yanmar KM4A) started having trouble finding the forward gear. A mechanic friend checked and found water in the transmission oil. I changed the oil, which fixed the problem (fortunately), but it appears that the transmission oil cooler is corroded. My friend bypassed the cooler (looped a hose from water output to intake on the engine) for the time being, so I can still use the boat for day sails without getting water in the transmission. He is ordering a new transmission oil cooler, and will be replacing it when it comes.

My question is this: do the experts in the group think that the transmission oil cooler is necessary when using the boat in water that rarely gets above 23 degrees C / 73 degrees F? The boat was originally built for the tropics, where both the air and water temperatures were somewhat higher. I'm not so concerned about short runs, but if I have to motor for 6-12 hours, should I be concerned? (I plan to replace the cooler in any case, but am interested in hearing whether people think it's money well spent!)

Thanks in advance.

Chris Moore
Hamilton ON Canada

[Clou]

Hi Chris!
I was wondering if you found some answers to your question? I just by-passed my KM4A transmission cooler because the casing is all coroded at the entrence of the cooler because of a bad gasket job.
Did you try to run the transmission for many hours?
Thanks!
Sebastien