Late in the year Carrie was advised that she had accrued some vacation that she would lose if she didn’t take it before year end, so the opportunity arose just before Christmas to take La Creole off her mooring and put her through some paces. We realized that with all of the repairs, upgrades and other reassembly conducted over the last 8 months we had yet to actually SAIL our sailboat, nor had we enjoyed any “chill time” at our favorite getaway, Christmas Cove. Time to remedy that!!
We didn’t get very far off of the mooring, however, before the coolant temperature began to rise to 190, 200, 210, and higher. Consequently we expeditiously returned via sail to the mooring and embarked on our next major project, to become intimately familiar with our engine’s cooling system and understand just how challenging it can be to work on her in the limited space provided.
As most of us know, there are two sides to the cooling system on most diesel engines, the raw (salt) water side and the fresh water (coolant) side, and there are a multitude of reasons for the temperature sensor in the coolant side to rise into dangerous territory. As I came to find out, even several which can occur on the raw water side.
We always check for raw water flow over the transom and there appeared to be no restrictions there so our attention was immediately focused on the coolant side. That wasn’t as clear cut as it seemed, but more on that later.
The remainder of our 5 days off found us troubleshooting the fresh water cooling system, which basically circulates coolant (a 50/50 mix of antifreeze and water) from the expansion tank through one side of the heat exchanger, though a jacket around the engine block and back through the tank. There is a thermostat that blocks this flow until the coolant heats up to, in our case, 180 degrees Fahrenheit to make for more efficient engine cooling.
Without knowing or having any maintenance history of this particular engine, we first flushed the system with water, and then ran a diluted muriatic acid solution through it in hopes of cleaning out unwanted scaling or other stuff that may be blocking the heat exchanger tubes. When that didn’t work we removed and tested the thermostat. That seems OK.
Then I reluctantly conceded to remove the heat exchanger and open it up to look for anything restricting flow. Wrestling this thing off of the side of the engine and out of the engine compartment was something I did on pure faith that it could even be done, and would prefer never to have to do that again. While it was out I thoroughly inspected as much of the insides as possible, gave the whole thing a bath in muriatic acid, replaced zincs and a plug on the salt water side, and reinstalled the unit along with numerous hoses that pipe the fluids around. It’s a real challenge to replace a hose where one end needs to be larger than the other, and a lesson learned to measure the piping on both ends before purchasing new.
This still didn’t resolve our overheating problem, and for weeks after our week-long “vacation” our free days were spent running the boat up wind so that if (when) she overheated we could sail most of the way back to the mooring and try something new. The next step seemed to be to replace the motor-driven water pump, which we had shipped in from Tortola, BVI. Despite the fact we were crossing international borders we found good availability and fast delivery from Parts and Power Inc. who made good use of the ferries making regular runs between the islands. Sorry, still overheating.
A possible solution that seemed a little far-fetched was to add a coolant overflow tank, something Perkins engines don’t normally come equipped with, but you can buy the parts in any automotive parts store so we added one. Nope, still overheating.
After several questions about checking the salt water side we felt we had no excuses left not to check there. Fortunately a previous owner placed a filter in the line downstream from the raw water pump, and when I opened it up I found 3 vanes broken off of the impeller that have been bouncing around in there for who knows how long. Obviously you can’t tell if there’s sufficient raw water flow by looking at the output over the stern. Replacing the impeller was something I did have experience with, but working on this engine always entails precautions against loosing things in our bottomless bilge.
Our regular outing the following week towards Christmas Cove demonstrated that we had almost figured it out, but not quite. We motored 90% of the distance (6nm upwind) before the temperature climbed to uncomfortable territory, and we were able to sail the rest of the way to a mooring. Finally!! We celebrated (sort of) by taking the afternoon off, snorkeling and enjoying our first getaway in months. We were still not out of the woods however, and the celebration was tempered by wondering how the weekend was going to turn out.
Over the weeks spent working on this project my lovely wife, who has more diesel experience than many cruisers we know, has been submitting that a possible issue may be that the spring-loaded cap on the expansion tank may need replacement if it can’t hold the pressure exerted by the hot coolant. From our mooring we were once again on the phone to Parts and Power in Tortola who put a new cap on the ferry to Red Hook the following morning. I jumped in the dinghy and picked up the part, along with some beer and other necessities, and returned to our mooring in Christmas Cove.
Someone told us once that one definition of Cruising is “repairs in exotic places” and it only seemed fair that we continue to enjoy the outing while working on the problem. The cap replacement took all of 5 minutes and when we returned to Crown Bay the following morning the temperature held steady at 180 degrees. YEA!!
Success came with great difficulty and considerable sweat, blood and tears on this one, but I did learn a lot about things like the value of perseverance and what to check first when the engine temperature rises. File all of this experience away for the times when we’re far from anywhere or anyone to fix things for us, because those are the some of the places worth visiting.
To be continued…