Gulp! No antifreeze in our Barrus Shire 1950

[Froggy]

Ok, thanks very much folks for all the very helpful contributions to this thread, which have helped us to determine that our coolant system has been changed from the one described in the Owner's Manual and, furthermore, that the boat now has an external skin tank.

 

This afternoon we drained what coolant we could and replaced by a 50-50 mix of water and antifreeze. I couldn't get the bottom pipe off that leads into the skin tank. It was stiff, the pipe union looked a bit rusty, and i really didn't want to tempt providence and end up with a broken connection. We removed the top pipe quite easily, which of course only drained a small amount of coolant, approx. 2 litres, but then with the advice of another boater removed the bottom pipe at the engine connection, which was a brass fitting and therefore much easier to remove. It's difficult to be sure how much coolant we got out, but i think it took best part of 20 litres to refill it. The refilling was done via the plastic expansion bottle visible in the second photograph of the top post. We then ran the engine for a while and checked the strength with a hydrometer. It was still a bit weak so i drained a few more litres out by removing the top pipe again, and this time replaced with a much stronger ratio of antifreeze. We'll keep a close eye on things over the next week or two to guard against leaks and/or overheating. I'll take another hydrometer reading at a later date when we're more confident that the thermostat opened up the circuit.

 

So, presumably there are both advantages and disadvantages of an external skin tank? One disadvantage, i would guess, would be a greater tendency to freeze owing to being in close contact with the canal water (but in the summer perhaps better cooling efficiency). Another is the danger of the tank being punctured/springing a leak and not being aware of this until the engine overheats. I'm guessing that the main advantage was ease of fitting when the engine was changed over.

 

As an additional thought, why on Earth does anybody use the system designed for the engine when the boat was built, i.e. using raw canal water to cool the exhaust circuit? According to the manual the mud box and a filter had to be cleared once a week - an unnecessary hassle imo, combined with the added risk of this circuit freezing and rupturing, and perhaps a pointer as to why the engine failed after only 7 years.

Get some in there before next weekend.☺

 

Yep, the forecast doesn't look great, but i don't have much faith in forecasts beyond a 24-48 hour window.

Edited January 9, 2017 by Froggy

[Froggy]

.Apologies-hadnt meant to confuse you -was trying to explain how a heat exchanged engine was different as you had asked :-) Have a look here- http://www.tb-training.co.uk/15cool.htm for a proper explanation . TB is a member here.

 

 

This has proved to be an extremely interesting and informative article, many thanks.

Edited January 9, 2017 by Froggy

[Bloomsberry]

 

So, presumably there are both advantages and disadvantages of an external skin tank? One disadvantage, i would guess, would be a greater tendency to freeze owing to being in close contact with the canal water (but in the summer perhaps better cooling efficiency).

 

Only the surface of the canal freezes which means the rest of the water below doesn't and as skin tanks are below the surface means that IMO the skin tank shouldn't freeze.

 

 

Another is the danger of the tank being punctured/springing a leak and not being aware of this until the engine overheats. I'm guessing that the main advantage was ease of fitting when the engine was changed over.

 

My skin tank got punctured but the engine didn't overheat, the coolant level reached the same level of the canal which was close to the normal working level and so ran ok. It was only when emptying the skin tank during a coolant change I found out of the leak when a constant dribble came out of the skin tank outlet. Edit - I'm refering to an external leak , are you refering to an interal leak ?

 

Edited January 9, 2017 by Bloomsberry

[Arthur Brown]

Antifreeze (glycol + corrosion inhibitors) is a dense liquid given the chance antifreeze put into an empty cooling system will largely settle at the bottom. As you put antifreeze mix on top of old coolant then you should be OK.

 

Were you able to run the engine for a while to warm and circulate the coolant?

[Froggy]

 

 

So, presumably there are both advantages and disadvantages of an external skin tank? One disadvantage, i would guess, would be a greater tendency to freeze owing to being in close contact with the canal water (but in the summer perhaps better cooling efficiency).

 

Only the surface of the canal freezes which means the rest of the water below doesn't and as skin tanks are below the surface means that IMO the skin tank shouldn't freeze.

 

 

Another is the danger of the tank being punctured/springing a leak and not being aware of this until the engine overheats. I'm guessing that the main advantage was ease of fitting when the engine was changed over.

 

My skin tank got punctured but the engine didn't overheat, the coolant level reached the same level of the canal which was close to the normal working level and so ran ok. It was only when emptying the skin tank during a coolant change I found out of the leak when a constant dribble came out of the skin tank outlet. Edit - I'm refering to an external leak , are you refering to an interal leak ?

 

 

 

Yes, i was referring to an external leak in an external skin tank. Thanks for the information, i think we'll take greater care when maneuvering anywhere near the starboard bank now we know we have an external skin tank.

 

Of course, maybe we already have a leak, which may account for the nonexistence of antifreeze in the system. I think i'll monitor this over the next few weeks.

Edited January 11, 2017 by Froggy

[Froggy]

Antifreeze (glycol + corrosion inhibitors) is a dense liquid given the chance antifreeze put into an empty cooling system will largely settle at the bottom. As you put antifreeze mix on top of old coolant then you should be OK.

 

Were you able to run the engine for a while to warm and circulate the coolant?

 

Yes, we ran the engine for a while but am not sure whether or not the thermostat opened so will ensure the engine has a longer run at the weekend before the coming cold snap. Thanks for this information, for some reason i thought it was the other way around owing to the way the pointer moves higher up the scale of the hydrometer the higher the concentration of antifreeze, and was worried that the purer antifreeze i added at the end would just sit at the top of the skin tank. If it is likely to sink to the bottom then it's presumably going to mix in with the rest of the coolant in the process, especially after it's been pulled through the engine block a few times. I'd been planning to drain some more coolant out of the lower pipe of the skin tank thinking this would be a relatively weak mix, but in view of what you say I'll leave it be since i have other jobs to do on the boat. I'll monitor the strength with a hydrometer a few times over the next couple of weeks (just in case the skin tank is leaking).

Edited January 11, 2017 by Froggy

[Froggy]

As a little postscript to this thread, I have to extend plaudits to Peter Taylor of E P Barrus Ltd. who has answered my queries promptly and, additionally, provided a copy of the Owners Manual for our Barrus Shire 1950, which will be of great use in the future. The manual, incidentally, recommends topping up with neat antifreeze when the coolant concentration is too weak.

 

EDITED to replace 'low' with 'weak'.

Edited January 12, 2017 by Froggy

[Neil Smith]

I always top up with neat antifreeze then run engine up to operating temperature so thermostat opens and water pump can circulate and mix it with existing mixture.

 

Neil

[Froggy]

I always top up with neat antifreeze then run engine up to operating temperature so thermostat opens and water pump can circulate and mix it with existing mixture.

 

Neil

 

My partner has run the engine yesterday to heat up some water for a shower (for some unknown reason our Eberspacher battery was never wired up to the main leisure bank and so doesn't charge via a shoreline). However, when I'm back at the boat over the weekend I'll make sure the coolant has been properly circulated before the projected cold spell early next week.