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      I have a 2004 B38 which has started to get water in the bilges after a period of motoring, at a rate of about a lt every 3 hours of motoring. It doesnt seem to leak when I am sailing, or when the boat is stationary on its mooring. I had a similar problem early on in the boats life, and it was traced eventually to the antisyphon valve, which I changed, and the problem went. I have a small collection bottle on the antisyphon vent pipe now, and as this bottle is empty, I dont think this is the problem area. I have checked around the engine whilst motoring, and cannot see any water leaking, so Im stumped on this one. Anyone have a similar problem?


        Hi Iain

        Does it happen when the immersion heater is on (and not motoring)? There is a pressure release valve on the calorifier which could be the source. Put some paper towel down around (under) all the pipe connections to the calorifier and see if there are any tell tale signs. I am assuming the water is fresh, not salty!

        If it is salty, is there any leak around the salt water pump or the pipes too/from the anti syphon.

        A further possibility is the wet exhaust system, but if you have checked around the engine you would probably have noticed this.

        Good hunting



          We have a similar problem which has got worse with time. It’s caused by a leak from the salt water pump mounted on the front of the engine. The leak is actually from the bottom of the perforated area behind impellor housing- run your finger under the pump when the engine is up to operating temp, to check. Be carefull of the nearby belts.
          Given that our boat was new in 2006 i’m less than impressed!


            It’s worth checking the exhaust elbow and the silencer. I’ve had problems in the past with corrosion in both components on my B32 ‘Another Fantasy’, resulting in raw water cooling leaks. Check the inlet and outlet pipes on the stainless steel end plates on the silencer and also the under surface of the exhaust elbow, where it’s connected to the exhaust manifold. My engine is a Volvo 2020 (2002 vintage), but I imagine that other variants will be similar.

            Ian Culley
            Another Fantasy


              Thanks for the suggestions guys, I will check those next time I go down to the boat. There doesnt seem to be any water in the engine compartment which would seem to rule out the water pump.


                We had fresh water in the bilge and after extensive searching found it came from a loose connection between the shower head and flex pipe in the heads locker.

                Good luck with the search


                  If it is fresh water then it is worth turning off the domestic water pump and opening a tap before motoring. It is just possible it is down to hot water expansion in the calorifier which is then venting into the bilges. Turning off the water pump and turning on a tap allows the system to vent through the open tap into the sink, (if it is a mixer tap it will need to be set on hot). When the calorifier is heated by the engine there is no maximum temperature control other than the cooling ability of the heat exchanger so unlike the regulated maximum heat of the emersion element when on shore power, with the engine running the water can overheat and therefore expand beyond the ability of the system to cope.

                  If opening a tap cures the leak then three things I would suggest looking are:

                  Check the Pressure Relief Valve on the calorifier is working correctly, it shouldn’t leak when the water is heated with the shore power (sounds like yours is ok).

                  Check that your water accumulator is charged as some of the expansion should be taken up by this, normally about 1.5bar pressure at rest, it can be checked/refilled using a tyre pump and a tyre gauge, (make sure the pump is off and taps are open when checking or refilling the accumulator).

                  Check that the domestic water pump pressure switch is set correctly, some have an adjustable switch, try turning the pressure down, depending on the system it should switch off between 1bar and 2 bar, (the lower the better when suffering from heat expansion)

                  Hope this helps,



                    I have just winterised my Bavaria 34 which will be on the hard in cold temperatures so we concentrated of frost protection. It was the first time i have had a good look at the calorifier and how it is heated. There was a small loss of engine coolant during the season and this was traced to a leak at the joint between the entry connection from the engine where the rubber pipe is attached to the front of the calorifier via a brass fitting onto the stainless steel tank. When we removed the brass fitting, which Bavaria have bedded on a sealing compound, we found it had 4 hairline cracks. On close inspection it appears that the brass fitting is not compatible with the calorifier as the brass thread is a taper and the stainless thread is parallel. It is probable that forcing the two fittings together to try to make a watertight joint has resulted in the failure. Whilst our loss of coolant was small, if neglected this leak would have become worse and eventually result in the loss of all or a large quantity of coolant allowing the engine to overheat. I would recommend that everyone checks these connections. I am currently trying to find the correct fittings to do the job properly and would appreciate input if anyone has already solved this problem.

                    Also i had a look at the pressure release valve which is on the cold water feed to the calorifier. It has a red knob, which if you turn it appears to open the valve to the cold water system rather than sending water under excess pressure into the boat.
                    Is that what it does and if so does that increase the pressure in the cold water pipework ,or does it return to the inlet side of the system?
                    Lastly i was pleased to find that Bavaria have left a drain pipe for the whole system in the front of the engine-bay, pity it’s not mentioned in the owners handbook. This made draining down the system very simple. We drained off all the cold water then opened one of the hot taps to allow the calorifier to breath and out came the hot water for a final wash down of the engine bay floor.


                      Late addition to this thread (2 years after), but I thought it may be worth adding to the “sum of knowledge”.

                      Our 2006 B37 had a freshwater leak into the bilges for 18 months before we finally figured the cause. Turns out that the welds on the Volvo calorifier had cracked, and were dumping water whenever the pump was switched on.

                      We also had a leak from the wonderful Volvo welding on the exhaust silencer / baffle. Good work from Italy, eh? 👿

                      We bought a new Sure-Cal calorifier from Surejust (http://www.surejust.co.uk/index2.html). It’s made of copper, makes hot water very quickly, and has a thermostatic mixer that claims to make your hot water last longer, by mixing hot and cold. Another advantage is that it’s been built properly in Sandown, Isle of Wight, and they will custom build a calorifier, if you like.

                      A tip is to turn all the taps off, and turn the water pump on. If your leak is on the pressurised side of the pump, the pump will run every few minutes. If on the cold side, the pump won’t run, but you’ll still be collecting water in the bilges.


                        How did you tackle the leaking exhaust?


                          I had a similar problem with ‘Another Fantasy’s’ exhaust. (See earlier posts…..). I had a local engineer re-weld the exhaust pipe spigots, using thicker metal. Seems to have worked OK, no recurrence this season.

                          Ian Culley
                          Another Fantasy

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