Direct or indirect cooling Perkins 404C-22

[aquaplane]

My new to me boat is fitted with a Marinised Perkins 404C-22 engine. I don't know who did the marinising.

I was lead to believe that it is raw water cooled.

On close inspection I note that there are 2 water pumps, the normal circulating pump you would expect on a plant engine behind the fan mounting, and another one similar looking to the Johnson pump on my Volvo MD11C.

There is a pressurised radiator cap, with a vent pipe into the bilge, mounted on top of the lump of casting that includes the exhaust manifold. There is no coolant expansion tank in evidence.

I can't think why there would be 2 water pumps or the radiator cap thing if it's raw water cooled, is this normal?

I would like it to be indirect cooling as I may want to fit a calorifier at some time.

When I started the engine the pink antifreeze and rusty water came out of the exhaust as I was expecting.

What do I look for to give a definitive answer?

 

[vyv_cox]

You may be confused. It sounds like it is indirectly cooled, the give-away is that it has a heat exchanger. Coolant in the engine is circulated through the heat exchanger, where it is cooled by raw water (sea or river) that passes through the exhaust hose, cooling it, and out through the skin fitting. No antifreeze should come out of the exhaust.

 

[VicS]

You may be confused. It sounds like it is indirectly cooled, the give-away is that it has a heat exchanger. Coolant in the engine is circulated through the heat exchanger, where it is cooled by raw water (sea or river) that passes through the exhaust hose, cooling it, and out through the skin fitting. No antifreeze should come out of the exhaust.

Unless it has been laid up / winterised with antifreeze in the raw water circuit

 

[aquaplane]

I put the antifreeze in to winterise the engine. I did wonder where the rusty water came from if it hadn't been sat in the block 4 months.
I just did what I did to winterise the Volvo, ran the engine to warm it up then poured 50:50 antifreeze in the raw water strainer, stopped the engine half a gallon of pouring later.

 

[Tranona]

Sounds like indirect cooling. Not all systems have an expansion tank. Take the pressure cap off the heat exchanger and check the level and that the coolant has antifreeze/inhibitor in it. as suggested the pink stuff coming out is likely antifreeze run into the sea water side. The water coming out of the exhaust is seawater. Your pipe runs should be from the seawater inlet (possibly via a strainer and maybe even an oil cooler for the gearbox) to a Johnson type seawater pump to the heat exchanger then out to an injection point in the exhaust.

To fit a calorifier you need to tap into the freshwater cooling system somewhere with a feed and return. Exact details vary from engine to engine.