How should I winterize the engine on a Hallberg-Rassy 37?
I'm preparing my Hallberg-Rassy 37 for its first winter laid up without running the engine. What order should I follow for the oil change, coolant checks and seawater antifreeze, and what changes if I leave her afloat?
Answer
Winterise your Hallberg-Rassy 37 by changing the engine oil and filter, checking the closed-circuit coolant, and flushing and frost-proofing the separate seawater circuit. Complete servicing and leak checks before the final antifreeze run, then leave the engine stopped until spring commissioning.
Identify the engine and cooling circuits
Many HR 37s have a Volvo Penta D2-55, but check your engine's model and serial number before ordering filters, impellers or coolant. Replacement engines and production changes mean the boat model alone cannot determine service parts or fluid quantities.
Keep the engine handbook beside you. Identify the seawater inlet seacock, strainer, raw-water pump, heat exchanger and exhaust mixing elbow. Check which gearbox or saildrive is fitted too; its oil specification and maintenance requirements are separate from the engine's.
Two cooling circuits need protection: the sealed circuit containing engine coolant, and the seawater circuit feeding the wet exhaust. Antifreeze in the expansion tank does not protect the seawater pump, the heat exchanger's seawater passages or the exhaust waterlock.
Change oil and service the engine
Warm the engine with its normal cooling-water supply connected. Stop it, then extract the oil through the designated suction tube or dipstick tube, as the handbook specifies. Warm oil pumps out more readily and carries suspended contamination with it.
- Replace the oil filter, checking that the old rubber sealing ring comes away with it.
- Refill with the handbook's oil grade and quantity. Check the dipstick rather than relying solely on the stated capacity.
- Run briefly with cooling water available and inspect for leaks. Stop, allow the oil to settle and recheck the level.
- Drain water from the fuel prefilter into a clear container. Replace fuel filters when due, bleed according to the handbook and check that the engine runs properly before preservation.
Inspect belts, hoses, hose clips, engine mounts and the exhaust elbow. Check whether the transmission oil is due for a change; investigate milky oil before storage. Record engine hours and the work completed. Fresh engine oil prevents the engine standing all winter with soot and combustion contaminants in its lubricant.
Protect both cooling circuits
With the engine cold, test the sealed coolant using a tester suitable for its glycol type. Set protection below the lowest expected local temperature. Around −25°C to −35°C is a useful target for many northern European lay-ups, subject to Volvo's specified mixture. Use the coolant specified for your engine; colour alone does not establish compatibility.