How should I winterize the engine on a Hallberg-Rassy 46?
I'm preparing my Hallberg-Rassy 46 for its first winter with me and want to winterize the diesel properly. What should I check and service, and how do I protect the seawater cooling system if the boat stays afloat?
Answer
Winterise your Hallberg-Rassy 46 by changing the warm engine oil and filter, checking antifreeze protection in the closed cooling circuit, and flushing and frost-proofing the seawater circuit. First identify the engine from its identification plate, as original installations and later replacements vary, and use its manual for oil quantities, coolant specifications and drain points.
Check the engine installation
The HR 46 normally has a shaft-drive diesel with separate freshwater coolant and seawater circuits. Coolant circulates through the engine; seawater passes through the heat exchanger and then into the exhaust. Some installations have additional coolers.
Trace the seawater hose from the inlet seacock through the strainer to the pump. Identify every cooler and drain point: protecting the engine heat exchanger alone can leave water trapped elsewhere.
- Have the correct engine oil, oil filter, fuel filters and sealing washers ready.
- Prepare a suitable suction hose, secure container, freshwater supply and compatible winterising antifreeze.
- Check the service record for coolant age, impeller replacement and heat-exchanger cleaning.
If working afloat, check that the inlet seacock closes properly before disconnecting any hose below the waterline. Keep a correctly sized emergency bung beside it.
Change oil and check fuel
Run the engine to normal operating temperature with its normal cooling supply, ideally during the final trip. Warm oil pumps out more completely, carrying away contamination that would otherwise sit inside the engine all winter.
- Stop the engine and extract the oil through the designated extraction point or dipstick tube, as specified in the manual.
- Replace the oil filter and check that the old rubber seal comes away with it.
- Refill with the specified oil grade and quantity, then check the dipstick rather than relying solely on the stated capacity.
- Run briefly with cooling water supplied and check for leaks. Stop, let the oil settle and recheck the level.
Drain water and sediment from the primary fuel separator. Replace fuel filters when due, bleed according to the engine manual and check that the engine runs properly before completing the cooling-system lay-up.
Leave a conventional diesel tank reasonably full, with space for fuel expansion. Investigate water or microbial sludge before storage; additives remove neither. Use a storage additive only if it suits the fuel and has the engine supplier's approval.
Protect both cooling circuits
Check the closed circuit when cold with a tester suitable for its coolant chemistry. Confirm frost protection below the lowest expected temperature, allowing a sensible margin. Replace overdue coolant with the specified type. Colour alone does not establish compatibility, and adding concentrated antifreeze without checking can produce the wrong mixture.