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Getting the water properly hot; why some engines have anodes; can you change types of antifreeze and BMC fuel pump leaks
QOur Volvo Penta 2002 raw water-cooled engine with wet exhaust provides hot water from a calorifier fed by the engine. The pipe that takes water from the thermostat housing to the exhaust elbow is cut into and the water is run (via the hose indicated in the picture) through the calorifier heating coil then to the exhaust elbow.
Water flows freely through the coil; the thermostat has been tested; but if I spend the day pottering at 1500rpm (about 3mph), the hot tap gives tepid water only. If we run at 1700rpm (about 3.5 mph) so the engine is working harder, the water is just warm enough for a fairly cool shower. What can I do to make it hotter? KEITH FROOM, via email
AOn a wet exhaust system there must always be sufficient water injected into the exhaust to prevent the exhaust hose burning, irrespective of the position of the engine thermostat. On direct raw water cooled engines this is usually achieved by having a fancy thermostat arrangement so that when the engine thermostat is closed the raw water bypasses the engine and is fed into the exhaust. As the engine warms up, more water passes through the engine to cool it; however there is always far more cold water than hot being directed to the exhaust so the flow is never much more than tepid.
On some engines it is possible to fit a distance piece to the thermostat housing mounting with a hot take-off from the engine side of the thermostat. On others it is possible to modify the pipework but as far as I can see from the manual a pipework mod is not possible, and there is insufficient information to be sure a distance piece (which would need machining and could be expensive) and take-off will work.
Contact your local Volvo Penta dealer in case there is an alternative calorifier take off point. You could also discuss the cost of modifying the engine to heat exchanger cooling, which would provide lots of really hot water.