header tank

[Keith.bryant]

I have a bowman heat exchanger on my bmc 1.8 which I want to service, how do I get to the tubes and wats the best way to clean them and what am I looking out for as in damages thank you for any help you can offer

Edited February 21, 2017 by Keith.bryant

[rusty69]

I can offer you no advice on the subject, but have noticed that a please goes a long way.

[cereal tiller]

I have a bowman heat exchanger on my bmc 1.8 which I want to service, how do I get to the tubes and wats the best way to clean them and what am I looking out for as in damages

Does the Engine have a Water cooled Exhaust and water intake,or a skintank and Dry Exhaust?

 

CT

[Keith.bryant]

skintank and dry I belive

Edited February 21, 2017 by Keith.bryant

[cereal tiller]

skintank and dry I belive

So ,you are referring to the casting with a Filler Cap on?Skin Tank/dry exhaust systems do not usually have a Tube stack inside them

 

In your set up the casting is used as an Expansion Tank and Partial cooling for the Exhaust Manifold

 

With a Wet Exhaust System the 'Raw' water (drawn from beneath the Waterline)pumps through the Heat Exchanger to cool the Recirculating water which is kept in the Engine Block and Head.

 

There should be no necessity to clean yours unless it is badly Scaled up

 

CT

[Keith.bryant]

thanks that explains a lot so basically the tank acts like an expansion bottle in a car, next question is how much water do I put in it as I have had water being forced out the over flow in a steaming jet, am I over filling and mistaking this for over heating

[ditchcrawler]

thanks that explains a lot so basically the tank acts like an expansion bottle in a car, next question is how much water do I put in it as I have had water being forced out the over flow in a steaming jet, am I over filling and mistaking this for over heating

Probably you are over filling if that is your only symptom

[Keith.bryant]

yes it's the only symptom I have, maybe a good idea to check the cap as well thanks for helping

[ditchcrawler]

After it has blown out when its hot, after you stop the engine and let it cool down can you still see the water level in the tank?

[alan_fincher]

t's hard to say if you are overfilling, without more detail.

 

The problem on a skin tank system, where no other expansion space is provided other than the Bowman tank, is that you are not just trying to deal with the amount of water the engine would have had in vehicular use with a radiator, but instead, are trying to deal with the massively greater amount of water that the skin tank contains.

 

Often these headers are not really big enough, and even if nearly empty when cold, may still eject water when hot, (not ideal, as every time you do this you are losing antifreeze, so if you don't top up with an antifreeze mix, you are constantly reducing protection).

 

On a previous boat adding a further external header tank of large capacity solved this problem.

 

However, your reference to the ejected fluid being a "steaming jet" worries me. These engines should not normally have a thermostat that is more than 82 degrees, so water ejected from the system should never be anything like 100 degrees, so should not boil as it comes out. If you are ejecting water that actually boils as it comes out, then by implication that bit of the pressurised system must be over boiling point, and that is simply wrong, being at least 18 degrees more than the thermostat should keep it down to.

 

Is your skin tank of adequate size and design for river use?

[Iain_S]

It's also worth bleeding the skin tank.

 

On Copperkins, before we fitted an expansion tank, the coolant would expand and overflow initially. If it then "found its own level", this was slightly below the top of the top hose. The air which collected there would pass into the skin tank, where it stayed, increasing the expansion/contraction of the coolant,resulting in an accelerating development of the skin tank air lock, which would cause the engine to overheat unless the skin tank was bled every couple of weeks. The air lock would develop even if the coolant was topped up to a sensible looking level daily.

[matty40s]

Quite a few boats I have moved- which have been sat for long periods- have overheated soon after setting off, and the skin tank being bled solved this problem.

[Mikexx]

thanks that explains a lot so basically the tank acts like an expansion bottle in a car, next question is how much water do I put in it as I have had water being forced out the over flow in a steaming jet, am I over filling and mistaking this for over heating

 

The only experience I have is of a water pump sufficiently corroded where there were no visible impeller blades left.

 

A stuck thermostat is another possibility and would be my first port of call, especially if the head was subject to frost and no antifreeze.

 

While others have wisely mentioned an airlock, my thoughts would be the pump at modest revs might overcome this potential head of water, none the less it is worth easing taking a pipe or two off and check for the seepage of water.

 

Has this 'just' occurred or has this been a long standing issue that has recently got worse? Is there a pipe from the head to your calorifier? Any recent changes or works carried out on the engine or water works?

Edited February 22, 2017 by Mikexx