EH 700 Clean freshwater side of heat exchanger-gctid397352

[tweekes]

I finally got around to cleaning my heat exchangers on the coolant side. I put in a bottle of gel dishwasher soap and filled with water. First hint is to use hose nozzle to dissolve it better. Then run the engine for an hour of so once up to temp. Drain, fill with water, run again and keep rinsing until you can no longer feel the soap in the water coming out. At flank speed (2600 rpm) I am usually just topping 175 on the temp gagues (summer water). After cleaning and with 92 degree summer seawater, it ran at 150 which I really don't understand since there is supposed to be a 175 or so thermostat in the cooling system. Anyway, I can't vouch for the actural temp numers since gagues often are inaccurate but I will say they registered 25 degrees cooler and both engines were the same. Some pretty unattracive stuff came out of the system on the first drain. Should be at least two weeks for my wrench hand to heal up getting the block drain open and closed. There must be some kind of bypass in the thermostat that allows the water temp to stabelize at different temps at different throttle levels.

[LTCret]

Were you getting 150 at cruise RPM or at idle?

Happy Boating

[tweekes]

At 2600 rpm cruise with 90 degree seawater.