Cooling tank losing water

[LadyG]

I have had problems with tank losing water after an hour, (I suspect I might have let it go too low!), needs a couple of pints of water, at first it was very low, needed maybe five pints at first, and used to gurgle and gulp.

Now, after about fifteen episodes it just needs topped up, a jug full.

I think it is OK when engine is not on.

The engineer bled it, I think it made a noise, but it is still losing water, no signs in engine hole, no leaky hose or at radiator cap.

Anything else I can do myself?

I might have a bleed key somewhere, and I now know where the stud is, does it need bled twice? There was no signs of loose water, if that is the term!

Edited July 20, 2022 by LadyG

[billS]

Have you checked your oil dipstick to ensure that there has not been a gasket failure?

 

[Tony Brooks]

24 minutes ago, LadyG said:

I have had problems with tank losing water after an hour, (I suspect I might have let it go too low!), needs a couple of pints of water, at first it was very low, needed maybe five pints at first, and used to gurgle and gulp.

Now, after about fifteen episodes it just needs topped up, a jug full.

I think it is OK when engine is not on.

The engineer bled it, I think it made a noise, but it is still losing water, no signs in engine hole, no leaky hose or at radiator cap.

Anything else I can do myself?

I might have a bleed key somewhere, and I now know where the stud is, does it need bled twice? There was no signs of loose water, if that is the term!

 

Normally when someone from the world of heat exchanger cooling (yachts) asks this type of question on a skin tank cooled boat my first reaction is overfilling but in your case this is less likely, if it was simple overfilling one would expect to see coolant leaking from the pressure/filler cap during warm up. Whether that ends up in the drip tray or bilge depends on design.

 

If it was air in the system expanding more than coolant  when heater the expelled coolant would end up in the same places. Sometimes, as air bubbles move through the circuit you have to bleed them several times, so apart from the fact you can't see any vented coolant it won't hurt to try.

 

Is your drip tray clean or does it have the typical oil floating on coolant in it. If the latter you may not see any lost coolant. Have a really good look below the engine water pump pulley for streaks down the front of the engine or coolant drops. Engine water pumps tend to be totally unreliable in their failure mode. Sometimes only leaking when running, sometimes only when stationary, and sometoes only when they think they will. If, by chance, it is the pump it will eventually get worse so fault finding is easier.

[LadyG]

26 minutes ago, billS said:

Have you checked your oil dipstick to ensure that there has not been a gasket failure?

 

Yes all well, tx

[LadyG]

20 minutes ago, Tony Brooks said:

 

Normally when someone from the world of heat exchanger cooling (yachts) asks this type of question on a skin tank cooled boat my first reaction is overfilling but in your case this is less likely, if it was simple overfilling one would expect to see coolant leaking from the pressure/filler cap during warm up. Whether that ends up in the drip tray or bilge depends on design.

 

If it was air in the system expanding more than coolant  when heater the expelled coolant would end up in the same places. Sometimes, as air bubbles move through the circuit you have to bleed them several times, so apart from the fact you can't see any vented coolant it won't hurt to try.

 

Is your drip tray clean or does it have the typical oil floating on coolant in it. If the latter you may not see any lost coolant. Have a really good look below the engine water pump pulley for streaks down the front of the engine or coolant drops. Engine water pumps tend to be totally unreliable in their failure mode. Sometimes only leaking when running, sometimes only when stationary, and sometoes only when they think they will. If, by chance, it is the pump it will eventually get worse so fault finding is easier.

I'll have another look, but did have a torch on it every day when it first started doing this, say two weeks ago, and maybe total  seven hours on the move, alternate days, one hour sessions.

At that time everything seemed normal, but then, there was some diesel spilt from the Webasto, at the same time, this has been sorted, just a few jubilee clips , stopped the drip, but the forward compartment of the engine bilge is not clean and dry, yet.

The engineer chap is away, and the aft engine bilge compartment does look wet, greasy, with emulsion spots, but this is not new, well not very new! I think it might be worse than normal, not sure.

I know I need to get it all cleaned, I have sourced a wet and dry vac, and a person. But not sorted it yet. There is no sign of water leaking from the hoses. No sign of water from the radiator cap or the water pump, but I think I ll need to run it to be sure, no water stains in that area.

As I have been topping up with a jug, and fairly near the top, but not right up to the overflow, there could be a bit of water splash, but I think it's unlikely.

It goes down about one inch below the level of the top half of the radiator thingy, which is about one inch above the metal that I can see when I look inside the radiator.

The engineer chap filled it up, and agreed that the amount it had lost, is one jug full was cause for concern. He filled it to same level as I had been filling. It lost another jugfull after an hour or a bit more running.

 

Edited July 20, 2022 by LadyG

[Tony Brooks]

16 minutes ago, LadyG said:

It goes down about one inch below the level of the top half of the radiator thingy, which is about one inch above the metal that I can see when I look inside the radiator.

 

If by "radiator thingy" you mean the manifold cum header than 1" below the cap is a very modest loss for a tank cooled boat and nothing to worry about. That would be the normal cold lever on a heat exchanger engine.

 

If you mean a separate header tank, possibly plastic, then, depending upon capacity, I would expect the normal cold level to be lower than that.

 

The way to establish the correct cold coolant level on a tank cooled boat with no leaks and has been properly blead,  is to fill almost to the brim, go for a cruise to get the  engine right up to running temperature, and allow it to cool right down. Whatever the level is, that is the cold top-up to level. If it is an automotive header tank ignore any marks moudled into the plastic.

[Tony Brooks]

PS, if the gearbox is a hydraulic one (PRM 150 etc) then make sure the gearbox oil is not emulsifying because it i possible a split oil cooler core could leak coolant into the gearbox, BUT the amount of lost coolant would probably mean the "oil" would now be flowing from the   gearbox breather. Unlikely but worth a check.

[LadyG]

2 hours ago, Tony Brooks said:

PS, if the gearbox is a hydraulic one (PRM 150 etc) then make sure the gearbox oil is not emulsifying because it i possible a split oil cooler core could leak coolant into the gearbox, BUT the amount of lost coolant would probably mean the "oil" would now be flowing from the   gearbox breather. Unlikely but worth a check.

Fortunately I think we determined it's a PRM 120.

There is no plastic tank.

[LadyG]

2 hours ago, Tony Brooks said:

 

If by "radiator thingy" you mean the manifold cum header than 1" below the cap is a very modest loss for a tank cooled boat and nothing to worry about. That would be the normal cold lever on a heat exchanger engine.

 

If you mean a separate header tank, possibly plastic, then, depending upon capacity, I would expect the normal cold level to be lower than that.

 

The way to establish the correct cold coolant level on a tank cooled boat with no leaks and has been properly blead,  is to fill almost to the brim, go for a cruise to get the  engine right up to running temperature, and allow it to cool right down. Whatever the level is, that is the cold top-up to level. If it is an automotive header tank ignore any marks moudled into the plastic.

Yes indeed, it's manifold cum header, I knew there would be a specific name, but felt a description would be better !

Does it actually need topped up every day, or is it just that I have never paid any attention previously, and this is the correct level. I suppose I could run the engine for a few more hours and see if level keeps dropping. The boat engineer did bleed it, and seemed to think it was not OK. He will be back next week, and I hope he can come back and sort a few things. He's recommended and seems a regular guy.

[Tracy D'arth]

Hope its not but a mysterious untraceable water loss could be a skin cooling tank leak to the canal when under pressure.

[bizzard]

14 minutes ago, LadyG said:

Yes indeed, it's manifold cum header, I knew there would be a specific name, but felt a description would be better !

Does it actually need topped up every day, or is it just that I have never paid any attention previously, and this is the correct level. I suppose I could run the engine for a few more hours and see if level keeps dropping. The boat engineer did bleed it, and seemed to think it was not OK. He will be back next week, and I hope he can come back and sort a few things. He's recommended and seems a regular guy.

I suggest removing the filler cap from the header, fill to about half, start the engine, run up to normal temp. Keep blipping the throttle whilst watching the coolant reaction in the header filler, if air is trapped it will bubble up and bounce up and down and disperse the bubbles, keep topping up if that happens. Sniff for any engine exhaust fumes emitting from the header filler, keep alert though in case it errupts in your face. If air bubbles continue errupting for a long time there's something wrong. If any bubbles cease, top up to your usual level and replace the filler cap.

Edited July 20, 2022 by bizzard

[LadyG]

10 minutes ago, Tracy D'arth said:

Hope its not but a mysterious untraceable water loss could be a skin cooling tank leak to the canal when under pressure.

I hope not.

The fact that it started off gurgling and no longer does so gives me hope.

Edited July 20, 2022 by LadyG

[Tony Brooks]

1 hour ago, LadyG said:

Yes indeed, it's manifold cum header, I knew there would be a specific name, but felt a description would be better !

Does it actually need topped up every day, or is it just that I have never paid any attention previously, and this is the correct level. I suppose I could run the engine for a few more hours and see if level keeps dropping. The boat engineer did bleed it, and seemed to think it was not OK. He will be back next week, and I hope he can come back and sort a few things. He's recommended and seems a regular guy.

 

On a well maintained and properly bled cooling system then no, the header tanks does not need topping up every day. The amount of coolant lost to evaporation is very low. However, it is vital that you do not top up to a cold level higher than that found as described above. If you over fill it then the excess will be expelled, so many think it needs topping up every day. If it leaks in any way then that is different.

 

Remember that unless you have found the volume of coolant in the system no one knows how much it holds so no one knows how much the coolant will expand so how much space needs leaving as an air gap above the coolant in the manifold.

 

I also hope it is not a leaking skin tank but on the bassis of what you have said at this stage I think it is less likely but not impossible.

[Momac]

Is the filler cap the spring loaded type and does it need replacing ?

[LadyG]

59 minutes ago, MartynG said:

Is the filler cap the spring loaded type and does it need replacing ?

It is but it seems perfect. There is no sign of staining on the top of the housing. The engineer chap and myself have inspected it, seems normal. I'll check the measurements against a brand new one, was there something about plunging in to boiling water?

Edited July 20, 2022 by LadyG

[bizzard]

14 minutes ago, LadyG said:

It is but it seems perfect. There is no sign of staining on the top of the housing. The engineer chap and myself have inspected it, seems normal. I'll check the measurements against a brand new one, was there something about plunging in to boiling water?

Plunging into boiling water is checking thermostats open not a cap.

[Chewbacka]

Try topping up, running till hot (cruising is fine), next morning when the engine is cold the coolant will be say an inch or two below the filler, make a note of the level (use you finger or a ruler), don’t top up.  Then go for another cruise (or whatever to get the engine to normal running temp).  Then next morning when it’s cold check the level.  If it’s the same you have found the cold filling max level.  If it is significantly lower then you are losing coolant.

[Sea Dog]

30 minutes ago, Chewbacka said:

Try topping up, running till hot (cruising is fine), next morning when the engine is cold the coolant will be say an inch or two below the filler, make a note of the level (use you finger or a ruler), don’t top up.  Then go for another cruise (or whatever to get the engine to normal running temp).  Then next morning when it’s cold check the level.  If it’s the same you have found the cold filling max level.  If it is significantly lower then you are losing coolant.

This (and what @Tony Brooks said earlier). In addition, check the neck of the filler - is there, as there often is, a small stub of metal tube there? Or even a plastic tube running from that stub? This is where the coolant will eject if you overfill or if the pressure cap is lifting for any other reason. If you direct this tube into a plastic bottle sitting in the bilge you'll be able to check that bottle when the engine is cool to see if (and how much) coolant has  been expelled, and also tell if none has.

[Tony Brooks]

45 minutes ago, Sea Dog said:

This (and what @Tony Brooks said earlier). In addition, check the neck of the filler - is there, as there often is, a small stub of metal tube there? Or even a plastic tube running from that stub? This is where the coolant will eject if you overfill or if the pressure cap is lifting for any other reason. If you direct this tube into a plastic bottle sitting in the bilge you'll be able to check that bottle when the engine is cool to see if (and how much) coolant has  been expelled, and also tell if none has.

 

And those little hoses often vent into the oily drip tray, not the bilge so the oil floats and obscures any small build up of water.

[LadyG]

On 20/07/2022 at 18:00, LadyG said:

Yes indeed, it's manifold cum header, I knew there would be a specific name, but felt a description would be better !

Does it actually need topped up every day, or is it just that I have never paid any attention previously, and this is the correct level. I suppose I could run the engine for a few more hours and see if level keeps dropping. The boat engineer did bleed it, and seemed to think it was not OK. He will be back next week, and I hope he can come back and sort a few things. He's recommended and seems a regular guy.

Need another engineer, as this "regular guy" turns out to be another one hour wonder.

Would two tins of Radweld do any good / any harm?

Edited August 1, 2022 by LadyG

[Alan de Enfield]

3 minutes ago, LadyG said:

Need another engineer, as this "regular guy" turns out to be another one hour wonder.

Would two tins of Radweld do any good / any harm?

 

You do seem to 'struggle' with tradespeople, do you think it is just bad luck ?

 

I tend to find that people respond 'in kind' and you "get back what you give", you are not their only customer, they do not have to come 'out into the wilds' to fix your boat, maybe try to be a little more accomodating and less adversarial and see if that helps.

[Tony Brooks]

12 minutes ago, LadyG said:

Need another engineer, as this "regular guy" turns out to be another one hour wonder.

Would two tins of Radweld do any good / any harm?

 

Hopefully any oil cooler tubes are larger than car radiator passages so even if it coagulates in the coolant there is a fair chance the system will not block However I have doubts that it will be effective.

 

Has anyone pressure tested the system? Unfortunately the cooling system pressure testers readily available seem to around £60 so rather expensive for a one-off job.

[Tony Brooks]

Also, I have not seen a report of the results of the procedure I gave to establish the correct coolant level and after subsiquent periods of running to temperature.

[Mad Harold]

1 hour ago, LadyG said:

Need another engineer, as this "regular guy" turns out to be another one hour wonder.

Would two tins of Radweld do any good / any harm?

I think you need to find a good engineer.Unless he's wearing a three cornered hat and sporting a brace of pistols, you don't know what you're getting.You will need to suck him and see. (pardon the expression)

Or post as many pictures of your engine gubbins as you can get, for Tony to offer advice.

 

[Tony Brooks]

13 minutes ago, Mad Harold said:

I think you need to find a good engineer.Unless he's wearing a three cornered hat and sporting a brace of pistols, you don't know what you're getting.You will need to suck him and see. (pardon the expression)

Or post as many pictures of your engine gubbins as you can get, for Tony to offer advice.

 

 

I don't think photos are going to help in this case. We know what she has got and what is reported as happening. The only thing we do not know are the results of the "find the correct coolant level" test I posted and what happens after subsequent runs up to temperature & cooling down again. It that shows definite coolant loss the next step is a cooling system pressure test, but goodness knows how many canal engineers have the kit to do one.