Beta Engine Cooling System

[CaptainBob]

I've got a calorifier system fitted to my Beta engine, which heats water in an insulated tank.

As a result, the expansion pipe on the cooling water cap at the engine is blanked off, and I have a plastic header tank (I think that's what it is, it's about 1.5 litres ish and has high/low marks) in a locker in the cockpit, about level with the top of the hot water tank.

Out of that header tank top, comes a short length of pipe which looks like it should work as an overflow - but it's got a screw in the end of it blocking it up.

When I ran the engine for a bit the other day, I noticed afterwards that cooling water had been pushed out of a pipe join which it clearly shouldn't have.

Aware that the cooling system should operate at pressure to avoid boiling the cooling water - I don't want to remove the bung in the little pipe, but if I don't it seems the pressure in the system builds enough to make it leak at this join.

Any thoughts?

Many thanks!

 

[leomagill]

Unblock the pipe and fit a new pressure cap to the expasion tank, make sure the seat the rubber seal sits on is clean, if the small pipe comes from just below the pressure cap it is just an overflow.
The filler on the engine itself should be a blank with no pressure valve in it as long as the expansion tank is at the highest point of the system.
If you fill the system right up it will blow out a fair drop of water due to the extra capacity of the system, especially with heat exchanger and watercooled manifold, I think it's about 4% water expands when it freezes so probably even more when it boils, mine blow about 1/2 litre after a full fill up and a good warm up then sit at the same level for ages.

 

[CaptainBob]

Thank you for that!

The pipe comes from high up on the side of the little tank, but looks as though if I unblock it, it will mean no pressure can build up in the system at all because it's directly into the tank - ie not behind some valve... so fitting a new pressure cap onto the tank then wouldn't do a thing.

The expansion tank is approximately half filled.

Does that change your advice?

 

[leomagill]

Sounds like it's just a spare then, leave it blanked and fix the join that leaks under pressure, check the cap is the right pressure for the cooling system or replace anyway if it looks at all dodgy.

 

[CaptainBob]

The cap is like this:

http://info.rockauto.com/getimage/getima...Stant/10244.jpg

But says "Volvo" on it.

That picture is a "closed system" coolant tank cap.

Seems odd.