Volvo 5.7 - Winterizing raw water side

[On_plane]

Hi guys,

I am in the process of winterizing my '93 Volvo 5.7 stern drive. My manual shows how to drain all the water from the block and the drive, but a Volvo fresh water cooling kit was added on, which the manual does not account for. This summer (when I first bought the boat), I filled the fresh water system with 50/50 antifreeze and water, so it's good for winter. What I'm not clear on is what I need to do in order to drain the raw-water side of the system. I see via the manual that there is a drain plug in the drive, but I'm not sure what to pull in the engine compartment to ensure I drain the raw water but not the fresh-water system. Attached are a few photos.

Photo one (engine overview) shows what I believe is the heat exchanger on the left side. Hoses to/from the coolant reservoir lead to that, however it looks like a hose from what I believe is the raw-water pump (second photo) also leads to the heat exchanger.

Is anyone able to offer some guidance as far as what I need to do to drain the raw-water system? I'm guessing pulling the hoses off the raw-water pump is required, but do I need to drain manifolds etc? Anything else I need to do with the heat-exchanger?


Thanks!

-Harrison

 

[Senior B]

You need to drain the manifolds, the heat exchanger, and the raw water pump. On the back of each manifold is a drain plug. Remove the plugs and stick a screw or something to poke around for blockage. Loosen the bolt on the lower cover of the heat exchanger. It's no big deal if it comes out but is more of a challenge to get back in cuz it's difficult to see. So pop the lower cover and gasket and the water will drain out. Frankly, I would go ahead and remove the lower bolt and take the cover off so you can feel in the lower part of the exchanger and clean out any junk that may be in there. I use the wife's hair mirror to get a better look in mine. Remove the hoses on the raw water pump. Believe that about has it..

 

[Horigan]

Agreed. Just follow the manual, except don't drain the block or the hoses going to the main water pump and thermostat. My OMC manual calls out clearing the water to the oil cooler, which is in the raw water system.

This link below has a good schematic of a closed water system on an OMC, which should be similar. You can try the link further below to find the Volvo version.

http://boatinfo.no/lib/omc/manuals/1...nual.html#/476

Rich

 

[ericga]

I have a similar setup but with V-Drives. I usually run the pink stuff through the raw water side and then drain the manifolds and heat exchanger as mentioned above. That way I'm sure there isn't any water trapped anywhere. I save the the drained pink stuff and use it to evacuate any water left in the bilge.

The top and bottom caps seals the raw water side of the heat exchanger. Take the opportunity to inspect the rubber gaskets and the o-ring/seals.