Hello all,
Just an update on our process. We only did this last week as we decided to wait until we were
on the hard in case we broke some tube or seal.
We removed the thermostat with very little trouble. The metal hoses/seals gave us no trouble.
Draining the old coolant took the most time due to our inexperience. The area near the drain-cock is very small and we had trouble trying to aim the flow into containers. Tip – open drain-cock fully. Initially, we turned it several times and thought the small amount of fluid draining was due to debris in the drain-cock. After using a wire to “clean” the drain, we accidentally turned the drain some more and the fluid flow increased dramatically. Tip – open reservoir for venting. This troubleshooting/trial and error took several hours. We finally decided to use a hose on the drain-cock to direct the fluid into our engine
bilge (separate from boat bilge). Once the liquid was in the
bilge, we pumped it out into containers using a cheap hand
pump. The draining of the coolant (ignoring the
learning curve) should not take longer than five minutes for each drain.
We flushed 3x with distilled water (by the 3rd flush, the water looked so clear we just didn’t think we would gain anything from a 4th flush, and we were cold – it was in the low 40s).
We calculated the total system capacity – 186 oz (from manual) plus 30 oz of additional hose (our coolant is also used to heat a water tank) - and added the right amount of 100% coolant, topped off with distilled water and we were done.
The old thermostat worked fine but we will replace it. One last tip, if doing this before
winter in the north, remember to bring the engine to operating temperature (open thermostat) after the coolant has been added. Otherwise, you will only have distilled water in the
heat exchanger.
Thanks again to all for the help.
edit: forgot to add, remember to burp system. We usually wait for at least 30 seconds after last bubble before stopping engine. On the final fill, we waited for a minute or two after the last bubble.