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Where is all the coolant going?


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13 hours ago, Eeyore said:

@BlueStringPudding Hi, any update on the coolant issue please? or still the same?

By the way did you check under the floor at the back of the boat?

Apologies for the delay in information, life stuff has currently got in the way of further investigation, BSP will update when life gets back to normal

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29 minutes ago, tree monkey said:

Apologies for the delay in information, life stuff has currently got in the way of further investigation, BSP will update when life gets back to normal

Hope all is ok with you two. Sending hugs.

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13 hours ago, MtB said:

 

I reckon Monkey is drinking it. 

 

That would explain EVERYTHING...

Have you seen the price of booze nowadays, it's not that bad if I'm honest, add a dash of lime...

3 minutes ago, Ange said:

Hope all is ok with you two. Sending hugs.

Everything's fine Ange, thanks

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1 hour ago, tree monkey said:

Have you seen the price of booze nowadays, it's not that bad if I'm honest, add a dash of lime...

Everything's fine Ange, thanks

Is good. You two are amazing good people 

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On 15/02/2024 at 03:03, tree monkey said:

Have you seen the price of booze nowadays, it's not that bad if I'm honest, add a dash of lime...

 

You can get green coolant now. Saves having to add lime... :)

 

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3 hours ago, cuthound said:

 

You can get green coolant now. Saves having to add lime... :)

 

 

 

You can get green electricity too now, apparently. 

 

Beats me how they know what colour it is though. 

 

 

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  • 2 weeks later...
  • 1 month later...
Hi all.  I thought I would give you an update about the mysterious disappearing coolant. A boaty neighbour who knows his engines has recently returned to the UK after a couple of months away,  and bless him, me and one other one of us pounced on him to ask for help with our respective engines!  He's a great chap and has been so determined that my engine won't beat him, he's been working on it for three days so far, eliminating possible causes and in the process discovering other, possibly linked problems, and resolving them as he goes. If you want the quick answer to what we think is the main culprit, skip ahead to the last paragraph.  But if you want to know what he's unpicked so far, read on:
 
So, the problem we're trying to solve is that the coolant system appears to be losing 600ml plus slowly over about 2 hours,  every time the engine cools down, as indicated by the indoor expansion tank, which is connected to the engine and Eber circuits. It's been losing coolant by emptying not through its overflow which would indicate engine overheating, but out through its lower pipework towards the engine, emptying slowly as the system cools. As you know from above, TM and another of my boaty neighbours checked around the engine and there were no obvious leaks that could account for this.  
 
Initial checks by this chap could also find no obvious leaks in or around the engine area either. His first thought that the initial overheat in February that started all this (whisp of steam, burnt coffee smell, boiling sound in the pipes) might have been caused by a sticky thermostat valve, but he was happy it was working fine.  He was also happy that the head gasket was fine. He did discover an air lock or blockage in the engine coolant system though. (Coolant coming through the pipe at the top front of the engine felt very hot  - but never hot enough to be pushed up into the expansion tank or out the overflow pipe from that tank into a bottle.  However the return pipes from the skin tank were almost cold and might not have had water in it at all.) He blew through the pipes and skin tank and then flushed through what he could there with water, and now the engine coolant is hot but not too hot at the front, and warm at the return from the skin tank, as it should be. But... as the engine cooled after a few good runs, the expansion tank lost coolant at the same rate as before, every time. To quote him: where is all the water going!? 
 
He discovered that the alternator belt between the starter alternator and the water pump wasn't fully on. It felt tight at the top but underneath he could easily turn the pump by hand. So he repositioned the belt and tightened it up. But that was a bit of a red herring with regards to being a cause for possible overheating, because that alternator belt had been changed *after* the initial overheat in February, (the old alternator belt being toothless in places 😲 ) He checked the radiator cap and other parts, and gave any potential risky bits a once over and a clean, but still no improvement.
 
He unblocked two tiny drainage holes in the bulkhead between the stern bilge and the cabin bilge, expecting water to come through from anything leaking the other side of the bulkhead. But there was no water, in fact his screwdriver came out dry. Also, uncovering the inspection hatch in the stern cabin floor showed no water. 
 
He eliminated the likelihood of there being a coolant leak from the calorifier by isolating it from the engine (as someone above suggested) joining two engine coolant pipes together to make a closed loop. But as the engine cooled after another couple of good runs, the expansion tank lost coolant at the same rate as before, till it was empty every time. But we still couldn't see where it was going to.
 
Yesterday he eliminated any radiators leaking being the possible cause, by capping off the relevant Eberspacher pipe. But as the engine cooled after another run, guess what?  The expansion tank still lost coolant at the same rate as before until it was empty.
 
So his attention went back to the engine area. There was a horizontal line of scale a few inches above the bottom of the skin tank, the baseplate next to it being currently dry. He scraped that scale away and a while later it revealed a slow weeping leak from near the weld. Running the engine made steam come from there, confirming there is a pinhole coolant leak from the skin tank into the bilge. The weeping skin tank leak is extremely slow, just damp, so not the location of 600ml plus coolant lost from the expansion tank every time the engine cools, but I'm pleased it's been discovered. The boat is booked in for some work at the boatyard next month so repairing that is now on their to-do list.
 
Meanwhile, the expansion tank is still losing coolant and being refilled repeatedly,  but there's still no water sloshing about anywhere. This morning, he again checked the pressurised header tank that is immediately above the engine and he could tell that the level had gone down a little since yesterday. Again, no puddles anywhere, and the expansion tank in the cabin has emptied overnight as usual. So he undid the pressurised radiator cap as well as the pipes that link the expansion tank inside the cabin to it. When I then filled the indoor expansion tank with water it should have drained out where he was standing by the pressurised engine tank, but it didn't. The pipe between the two was blocked. So after a few hefty puffs he blew the pipe clear and I flushed it through with water
Once the expansion tank was full and the connecting pipe clear,  it was obvious that the radiator cap even when not under pressure was dripping. When checked last month and again this weekend, the radiator cap appeared to be working fine, but now it's obvious that it just doesn't seal properly.
 
So his prevailing theory about where all this coolant has been going is that it may have been coming out of the knackered radiator cap as steam and/or drips, because the pipe from it into the expansion tank was almost but not entirely blocked - so coolant couldn't expand into the expansion tank. But the coolant wasn't collecting in puddles on the baseplate or anywhere else either to make this obvious.  And although the engine thermostat appears to be working fine, on the off-chance that it may have stuck shut in the past, I've ordered a new one and he's going to replace it as a "belt and braces" way to ensure all this shouldn't happen again. So fingers crossed that the case of the mysterious disappearing coolant will have been solved. But we shall see when the parts are replaced!  Thanks to TM, everyone here and my three contributing neighbourinos for their help with this. Let's hope these two replacement parts and all the unblocking of pipes and budging of airlocks has fixed it. 
 
🤞
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