How do I winterise the Volvo Penta engine on a Hallberg-Rassy 31?
I need to lay up my Hallberg-Rassy 31 for the winter ashore. She has the original Volvo Penta engine. What is the exact sequence for winterising the engine and saildrive properly so I don't get any frost damage or starting issues next spring?
Answer
To winterise the Volvo Penta MD2020 or D1-20 on a Hallberg-Rassy 31, replace the engine oil while warm, flush the raw water circuit with fresh water, and fill it with a 50/50 propylene glycol antifreeze mix. Changing the saildrive oil and treating a full diesel tank with biocide will complete the job and prevent internal corrosion or diesel bug over the winter.
Oil and Fuel Systems
Run the engine under load to warm the oil and suspend the contaminants. Extract the old oil via the dipstick tube using a vacuum extractor. The MD2020 holds 3.5 litres. Change the Volvo Penta oil filter (part number 861473 costs around £15). Smear clean oil on the rubber gasket. Tighten it exactly half to three-quarters of a turn by hand after the gasket makes contact with the block. Refill with 15W-40 mineral marine diesel oil.
Top up the HR 31's 60-litre stainless steel fuel tank to 95 percent capacity to minimise condensation on the tank walls. Dose the fuel with a marine biocide like Marine 16 or Grotamar. Drain a small amount of diesel from the bottom of the primary water separator (often a CAV Delphi 296 unit). This ensures no water sits in the glass bowl over winter and cracks it during a freeze.
Flushing the Raw Water Circuit
Flushing stops frost damage in the heat exchanger, the Vetus exhaust waterlock, and the saildrive leg. Close the saildrive raw water seacock. Disconnect the raw water inlet hose from the seacock or the strainer. Submerge the hose end into a 10-litre bucket fed continuously by a freshwater hose. Start the engine and run it at a fast idle for 10 to 15 minutes to flush the salt out of the system. Never let the bucket run dry while the engine is running. You will melt the raw water impeller in seconds.
Turn off the engine, empty the fresh water from the bucket, and pour in 5 litres of pre-mixed propylene glycol antifreeze (pink, rated to at least -25°C). Restart the engine and watch the exhaust outlet at the transom. As soon as you see the coloured antifreeze spitting out with the exhaust gases, shut the engine down immediately. This leaves the entire raw water circuit protected against freezing and internal corrosion.
Coolant and Impeller Care
Check the strength of the internal freshwater coolant in the header tank using a hydrometer. It must offer frost protection down to at least -25°C. Volvo Penta coolant (either green or VCS yellow) requires a complete flush and replacement every two years. Do not mix the two colours. They will coagulate and block the heat exchanger.