Volvo Penta Winterization Guide

A Volvo Penta sterndrive or inboard is a bigger job than an outboard for one reason. An outboard drains itself when you tilt it down. Your engine holds water in the block, the manifolds and the hoses, and water left in a block that freezes will crack it. That is the expensive failure this whole procedure exists to prevent.

For the general walkthrough, start with the boat winterization guide.

What your Volvo Penta needs

Fuel first, with the engine running

Gas: add stabilizer to a nearly full tank and run the engine long enough to pull treated fuel through the water separating filter and into the injectors.

Diesel: the problem is different. Diesel does not go stale the way gas does, it grows microbial contamination at the fuel and water interface in the tank. Treat with a biocide, leave the tank as full as you can so there is no room for condensation, and drain the water separator.

Either way, change the fuel filter before storage rather than after. A filter full of last season's water is not what you want sitting in the engine room all winter.

Oil and filter while the engine is hot

Do it before you drain the cooling system. Used oil holds acid and water, and five months in a warm engine room is plenty of time for that to do damage. Use the oil grade Volvo Penta specifies for your engine, with a new filter. Diesel engines are particular about oil specification, so use the book rather than a general purpose marine oil.

Now get the water out. This is the step that matters

Know which system you have. A raw water cooled engine pulls sea water straight through the block. A closed cooling engine circulates coolant through the block and uses raw water only through a heat exchanger. Both have raw water somewhere, and raw water freezes.

  • Open every drain point. Block, manifolds, heat exchanger, oil cooler, hoses. Some Volvo Penta engines have a self draining system and some do not, and a drain that is plugged with scale looks exactly like a drain that has finished draining. If it does not run, poke it clear
  • Run non-toxic antifreeze through the raw water circuit until it comes out the exhaust at full strength. Plan on three to four gallons on a typical sterndrive, more on a bigger inboard
  • Close the seacock and pull the raw water strainer basket. Clean it and leave it empty
  • Automotive green antifreeze does not go in a raw water circuit. Pink non-toxic is the correct product

If you have closed cooling, test the coolant in the closed loop. It has a freeze point and a service life, and coolant that is out of spec protects nothing.

The drive

The drive is a separate job from the engine and it does not get skipped.

  • Drain the drive, read what comes out, refill with the specified drive oil. Milky oil means water past a seal, and that is a repair to book now rather than in the spring queue
  • New sealing washers on the plugs. Cheap parts, most skipped item on the list
  • Top the drive oil reservoir
  • Grease the steering and the U-joints, and look hard at the bellows. Cracks, soft spots and chafe are much cheaper to find in October
  • Store the drive in the full down position so it drains and the bellows are not stretched

Impeller

The sea water pump impeller is a wear item on a schedule, not a lifetime part, and on a Volvo Penta it is doing the whole cooling job for the engine. Read what your manual says for your model.

Fall or spring both work. The case for fall is that an impeller which sits all winter with its vanes bent in one direction takes a set, so a marginal one in October is worse in May. The other case for fall is simply that if a vane has already broken off, the pieces are sitting somewhere in your heat exchanger right now and you would rather find them before a season of running than after.

Buy the full kit rather than the bare impeller. The wear plate, gaskets, cover and seals in the kit are the reason people do this job twice.

Finish it

  • Check the anodes on the drive, the trim tab and anywhere else your model has them. More than half gone means replace now
  • Batteries off the boat, terminals cleaned and coated, on a maintainer
  • Pump the bilge dry and leave the plug out
  • Moisture absorbers in the cabin
  • Cover it with vents, and stands if it is coming out of the water

Volvo Penta covers a lot of ground, from a four cylinder gas sterndrive to a big common rail diesel, and the right fluids are different for each. Call us at 631-722-5700 or send us your model and serial number and we will match it. Always check your Volvo Penta owner's manual for drain locations, capacities and service intervals for your specific engine and drive.