How should I winterize the engine on a Malö 36?

Winterise your Malö 36 by changing the engine oil and filter, checking the closed-circuit coolant's frost protection, and flushing and protecting the seawater circuit. Start with the engine identification plate and manual: the installed engine, including any replacement, and its seawater plumbing dictate the fluids, quantities and drain points.

Identify and service the engine

Do not order a winter service kit by boat model alone. Malö 36 installations vary with build year and later engine changes. Record the engine model and serial number, then locate the seawater inlet seacock, strainer, pump, heat exchanger and exhaust waterlock.

Most installations have two separate cooling circuits. Antifreeze coolant circulates inside the engine; seawater passes through the heat exchanger and leaves through the exhaust. Protecting one does not protect the other.

1. Run the engine to normal operating temperature with its normal cooling-water supply, preferably under load before laying up.
2. Stop the engine, extract the warm oil through the designated extraction pipe or dipstick tube, and replace the oil filter.
3. Refill with the oil grade and quantity specified for that engine. Lubricate the new filter seal and tighten according to its instructions; there is no universal filter torque.
4. Run briefly and check for leaks. Stop, let the oil settle and check the dipstick again.

Change the oil before storage so soot and acidic contaminants do not sit inside the engine all winter. Check the gearbox oil separately. While access is clear, inspect belts, engine mounts, hoses and clips.

Protect both cooling circuits

With the engine cold, check the coolant level and test its frost protection with a tester suited to its glycol type. A 50:50 mixture commonly protects to around −35°C, but follow the coolant specification and local minimum temperature. Matching colours do not mean coolant technologies can be mixed.

For the seawater circuit, use an inhibited antifreeze approved for engine winterisation and compatible with the installation. Follow its dilution instructions. The advertised burst protection may differ substantially from its freeze protection.

Keep hands clear of belts, vent exhaust gases outside and never remove a hot coolant cap.

1. Close the seawater inlet seacock. If afloat, check that it holds before disconnecting any hose below the waterline. Have a correctly sized softwood bung ready.
2. Following the arrangement in the engine manual, connect a suitable suction hose from the seawater pump inlet to a secure container of fresh water.
3. Run at idle, keeping the suction end submerged and supplying enough water. Never let the impeller run dry or connect mains pressure directly to the engine.
4. Stop the engine before switching to a container of correctly prepared antifreeze. Then run until the circuit contains an adequately concentrated mixture.
5. Collect the exhaust discharge for proper disposal without obstructing the outlet.