How should I winterize the engine on a Hallberg-Rassy 34?

Winterise your Hallberg-Rassy 34 by changing the engine oil and filter, checking frost protection in the sealed coolant circuit, and flushing and protecting the separate seawater circuit. First read the engine identification plate, as the correct fluids, capacities and drain points depend on the engine fitted.

Identify the engine first

Many HR 34s have a Volvo Penta MD2030, but early installations and replacement engines differ. Order service parts against the engine model and serial number. Keep its operating manual beside you and locate the seawater inlet seacock, strainer, impeller pump, heat exchanger and exhaust waterlock before starting.

Hallberg-Rassy's lay-up guidance calls for preparation when the engine will stand idle for more than two months. Occasional harbour starts do little good unless the engine works under load and gets thoroughly hot.

1. On the final outing, bring the engine fully up to operating temperature under load.
2. Stop it, extract the warm oil through the dipstick tube with a suitable pump, and replace the oil filter.
3. Refill with oil meeting the engine manual's specification. Start below the stated capacity, then adjust using the dipstick.
4. Run briefly with cooling water supplied, check for leaks and stop. Allow the oil to settle, then recheck the level.

Change the oil before the final seawater winterising run. Fresh oil prevents the engine standing for months with soot and acidic contamination in its lubricant. Follow the relevant manual for filter tightening and drain-plug torque.

Check the sealed coolant circuit

A freshwater-cooled diesel has two cooling circuits. Coolant circulates through the engine; seawater carries heat away through the heat exchanger. Antifreeze drawn into the seawater pump does not renew the coolant inside the engine.

With the engine cold, check the header-tank level and test coolant strength with a tester suitable for its glycol type. A roughly 50:50 mixture commonly protects to around −35°C, but follow the coolant manufacturer's figures and the engine's specified concentration.

Replace coolant if its age or chemistry is unknown, or its change interval has expired. Use the Volvo Penta specification for that engine; colour alone does not establish compatibility. If the domestic hot-water calorifier is connected to the engine, its heating coil and hoses form part of this circuit and must also contain properly mixed coolant.

Protect the seawater circuit

Run the engine only with cooling water supplied and exhaust gases safely ventilated. Keep hands clear of belts and collect discharged antifreeze for proper disposal.

1. Close the seawater inlet seacock and clean the strainer. Connect a securely supported temporary supply hose to the pump inlet or the strainer's engine-side connection.
2. Let the engine draw fresh water from an open bucket and keep the bucket topped up. Never pressurise the engine with a mains hose.
3. Flush until fresh water has displaced the salt water, then switch the supply to premixed antifreeze approved for winterising marine engine raw-water circuits.
4. Continue until the mixture reaches the exhaust outlet and its tested strength meets the product's required protection level. Stop before the bucket empties.
5. Follow the engine and exhaust-system instructions for any remaining drain points, including the waterlock where specified.