As we moved the boat from Burrard Civic to its new home in Heather Civic Marina I noticed a weird sound coming from the back of the boat, it sounded like air type sucking sort of noise.  I also had a lot of white vapor (I’m pretty sure it was vapor) coming out the back, we weren’t really spitting much exhaust water out either, but the raw water filter appeared to have a good amount of water in it still.  At that point I figured it was a good idea at that stage to consider doing some maintenance to the cooling circuit.

Now I had requested the the heat exchanger be serviced when I first got the boat, but after this round of work its debatable that it was done.  I started by draining the cooling fluid out the bottom of the heat exchanger as well as what raw water was still in there, and it wasn’t much!  I got the exchanger off and pulled all the hoses and threw it all into a bag to bring home.  I also ordered new seals, o-ring and the screw that holds the end cap down cause there was significant leakage on the one end as well as lots of calcification.

The hose that runs from the raw water pump to the heat exchanger was actually held in its shape by all the build up that was within it, a good exercising of the pipe and a nice bath in CLR and hot water did an excellent job of cleaning it out.  At the end of the heat exchanger I had a massive pile of buildup so that also received a bath and I used some bamboo skewers to work it all off.  After I took a wire wheel to get all the old paint off the outside of the heat exchanger and any corrosion and gave it a good coat of primer and black indoor/outdoor paint.  It looks pretty good now!

The real fun began after I got it all back together, I had elected to leave the thermostat for now because I didn’t have anything on the boat that I could use to turn the cap screws that held it on, as it turned out they were massively rusted into place, but we’ll come back to that in a moment.  With everything back together, and a new cooling fluid in as well as a new impeller I fired up the iron sail and let her warm up to make sure everything was ok.  As it turns out everything wasn’t ok, I think I had an air trap in the thermostat housing which caused an over heat, I was able to alleviate that by opening up the little valve on the top, but now I was concerned that the thermostat could also be sticking.  I did have a new thermostat and gaskets, and so began stage two!

I went and bought a nice big 1/2″ ratchet drive so I would have lots of torque to try and break the one bolt free, which I was able to do, the problem now was that the second bolt head had been stripped years previous it seemed as well as being rusted in place.  Back out to get some more tools and back to the boat with a dremel tool now to cut the bolt head off.  Once I made it through that, which was a little bit of a chore due to the lack of space to work the housing came up leaving me to just deal with the bolt stem still.  I was getting worried that I would need to drill it out and I really didn’t want to have to do that, so I borrowed a friends pipe wrench and that did the trick!

With the housing now free, and new bolts on hand, I cleaned up the water pump mount and painted it, I left the thermostat housing as it was at this point, I was just tired of grinding metal and painting!  I headed back to the boat and cleaned up the base and put my new gaskets into place and bolted everything down.  Hooked the water pump back up and fired up the engine!

With the engine fired up, and a good flow out the back I patiently waited for the engine to get up to temperature.  180F came, and there it stayed, the temp guage would creep up a few more degree’s then instantly come back to 180F as the thermostat opened up.  I put the boat in gear and few times and let the engine run at some higher RPM’s and all was well.  Looks like that task is now complete, all that is left to do is change the transmission fluid and engine oil and we are good to go!