Header Tank

[RobinJ]

No problems at all - the query was exactly where I should put antifreeze! I've kept the one header tank topped up with it, but was curious whether I should also be putting it in something else more obviously enginey?

I know my cap blows water out when it gets warm and makes a sucking noise when its cooling down!

 

How about finding a way of draining water from the engine and the heating circuit.

Locate the 'other' header tank, fill it up with antifreeze, drain some water from the engine side, fill it back up and drain some water from the heating side, that way you are sure there is antifreeze in each system?

[RLWP]

I know my cap blows water out when it gets warm and makes a sucking noise when its cooling down!

 

How about finding a way of draining water from the engine and the heating circuit.

Locate the 'other' header tank, fill it up with antifreeze, drain some water from the engine side, fill it back up and drain some water from the heating side, that way you are sure there is antifreeze in each system?

 

I think it may be time to apply the principle of "If it aint broke, don't fix it". It sounds like it has worked Ok for years, why change it?

 

Richard

[BlueStringPudding]

Perhaps I'll just keep putting antifreeze in the one header tank, and not worry about it, in that case.

[Machpoint005]

Perhaps I'll just keep putting antifreeze in the one header tank, and not worry about it, in that case.

Have you lost/used/mislaid enough water/antifreeze mixture to render this necessary?

[bottle]

I know my cap blows water out when it gets warm and makes a sucking noise when its cooling down!

 

How about finding a way of draining water from the engine and the heating circuit.

Locate the 'other' header tank, fill it up with antifreeze, drain some water from the engine side, fill it back up and drain some water from the heating side, that way you are sure there is antifreeze in each system?

 

I think that this implies that it is being overfilled.

[alan_fincher]

I think that this implies that it is being overfilled.

A lot of marinised engines seem to have so called "header tanks" that are really too small to cope with the expansion of the large volumes of water found in the skin tank, and possibly calorifier circuit.

 

BMCs marinised with a Polar or Bowman tank on the engine seem only to not spill out water when hot, if the tank is nearly empty when cold.

 

I gather the same is also true of some Vetus or Isuzu engines, but have no experience myself.

 

I can never quite believe how much the water expands when things are working normally.

 

A separate plasic expansion bottle is probably sensible on such engines, but seems to be remarkably rarely fitted.

 

Alan

[RobinJ]

A lot of marinised engines seem to have so called "header tanks" that are really too small to cope with the expansion of the large volumes of water found in the skin tank, and possibly calorifier circuit.

 

BMCs marinised with a Polar or Bowman tank on the engine seem only to not spill out water when hot, if the tank is nearly empty when cold.

 

I gather the same is also true of some Vetus or Isuzu engines, but have no experience myself.

 

I can never quite believe how much the water expands when things are working normally.

 

A separate plasic expansion bottle is probably sensible on such engines, but seems to be remarkably rarely fitted.

Confirmed!

Stainless Steel in this case.

I was referring to the cap on the heat exchanger passing water both ways as it is this that allows water in and out of the expansion tank!

[tosher]

On my engine installation (Isuzu) I have a vertical calorifier and the header tank is mounted higher up in a cockpit locker. I noticed that the pressure cap on the header tank is the same calibration as the pressure cap on top of the engine heat exchanger, ie. both settings are 95kpa. When the engine is working hard, expansion takes place ok into the header tank and the level rises but I also loose a bit of fluid out of the relief valve on the engine pressure cap. Are these calibrations corrrect ??? or should the lower cap be a higher setting or even a blank to ensure expanding water goes up into the header tank? tosher.

[RobinJ]

On my engine installation (Isuzu) I have a vertical calorifier and the header tank is mounted higher up in a cockpit locker. I noticed that the pressure cap on the header tank is the same calibration as the pressure cap on top of the engine heat exchanger, ie. both settings are 95kpa. When the engine is working hard, expansion takes place ok into the header tank and the level rises but I also loose a bit of fluid out of the relief valve on the engine pressure cap. Are these calibrations corrrect ??? or should the lower cap be a higher setting or even a blank to ensure expanding water goes up into the header tank?

It will depend on where the take off for the header tank is?

A heavier pressure cap can be fitted or a plain sealed type, however, with a heavier pressure cap there will still be water head when it opens and water will ouze from any gaps!