Engine Cooling

[alahol2]

I'm sure I'm going to feel silly in a minute....
In a modern indirectly cooled engine there is a raw water cooling pump with an impeller to push the water through. But what circulates the fresh cooling water? I can't see what does it, is there another pump with impeller somewhere?
Specifically this relates to a Beta 13.5 but probably to others as well.

 

[Avocet]

Don't know anything about the Beta engine but most car diesels have a water pump stuck on one end of the engine driven by the cam belt on overhead cam engines and by the fanbelt on engines with chain driven cams. Look at all the pulleys the belt(s)? goes round and one of them will probably be the water pump. Typically it will bolt on to the front of the engine block with a number of bolts and the impeller is directly on the back of the relevant pulley.

 

[steverow]

Same as a car, a water pump usually built in to the front of the block probably lurking just above the flywheel somewhere. Look for a bulbous bit with about 10 bolts in it roughly circular in shape.

Dont forget that most marine diesel engines start life as ordinary truck,van or generator engines, depending on size. The seawater cooling bits are added later.
But they all are based on a standard production block of some sort.

Steve.

 

[scarlett]

Or as on the VP 2020 the fresh water pump appears to be just a bulge with two pipes attached.

 

[MarkJohnson12345]

Can't be specific on the Beta, but my Bukh 20 which has a MArtec heat exchanger has an electric pump to circulate the fresh water in the engine and calorifier.

I did have a Beta 13 new in 2000, on my old boat. As it was designed to be freshwater cooled, I imagine it would have a mechanical water pump built in.

 

[alahol2]

Thanks all, I thought there must be one somewhere. Am I right in supposing that the impellers in this type of pump don't give up the ghost like the rubber seawater impeller? I've never yet had to change one in a car.

 

[tugboat]

The fresh water pump is a centrifugal pump with a cast metal impellor. They are maintenance-free unless a bearing wears out.

 

[A1Sailor]

Might it be driven by the "drive belt"? If you look on the front of the engine, the belt goes round the crankshaft pulley, the alternator and another pulley. The fresh water pump might be in line with this.

 

[macd]

I assume your referring to a Beta BZ482, which uses conventional automotive practice. You'll see that there are three pulleys on the front of the engine: one on the end of the crankshaft, one on the alternator and the third (the topmost one) driving the engine coolant pump. As other posters have written, under normal circumstances the pump is maintenance-free, although obviously if the belt breaks, the pump stops.

 

[alahol2]

That's what comes about thinking too much at home. If I'd looked at the engine, as I have now, the pipes might have given it away! Anyway, thanks to all who have replied. And a special thanks must go to the Beta representative who has the responsibility of monitoring the forums, he phoned me at work to ensure I fully understood the workings. That really is service above and beyond!