Loosing Coolant

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Genoa

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Hi All,
I have a Volvo 2030 with a heat exchanger cooling system and I am loosing a small amount of coolant from the freshside - about 200ml in a week of use - say 25 hours.
I have recently bought the boat so don't have a history, but the previous owner tells me no known faults exist. It's done approx 1000 hours.

What would be your SEQUENCE of checks?
 
First question, are you simply trying to keep it too full. If you dont top it up will it continue to loose water or will it stabilise at the lower level. (Must admit though that 200ml is a bit much)

Some have an expansion tank with a level sensor ... one of those?

Is it losing it via the pressure cap and overflow. possible defective cap.

Look at all the hoses and connections esp the end caps on the heat exchanger.

coolant pump OK, not leaking.

Leaking into the seawater side via one of the heat exchanger end caps?
 
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I am opening the cap on the exchger and just covering the internal pipes. The expansion tank is empty, but when the engine is running (afer 1-2 hours) I get maybe 3-5% in there.
The 200 ml is maybe a bit of an over estimate ...
 
Second vote for the rubber caps on the end of the heat exchanger. Someone mentioned here about losing coolant from the water pump, which being tucked away, is not easy to see.
A
 
Coolant Loss

Also agree, tighten both ends of heat exchanger rubber end circlips small and large and hopefully the problem will go away.There may be brown stains around the circulation pump, not the raw water pump, suspect pump bearings if so. No trouble on mine yet and it has lots of hours run, except that loose end cap thing on a previous 2020 in last boat.Good sailing to all!
 
I had a similar problem with the same symptoms on my Perkins 4-108. I tried all of the checks that have been already sugested, and I could not solve the problem. My loss of water only occurred after the engine had been run. It never lost water if it was filled then left. This went on for several years with me just constantly checking and topping up. I eventually found the cause. It was a leak from the water pump which was so slight that it only occurred when the engine got hot and the pressure increased and the tiny leak was so slow that it was being evaporated by the hot engine, and thus no pool of water showed up. I found this out when the leak got worse, it was still very small. When I replaced the pump the leak stopped. Water level is now steady.

Best of luck
 
Genoa

I have the same problem on the same engine. The coolant loss is sufficient to lower the level below the top pipes in the heat exchanger. The coolant was collecting in the bilge and it seemed it was being lost through the overflow pile. I was told by a Volvo engineer that this is a common problem and Volvo produce a purpose made expansion tank which is fitted to many of these engines. However the cost fitted would be approximately £200.00 so I loose fitted a plastic lemonade bottle on the starboard side of the engine and inserted the the plastic overflow pipe in the top. The bottle does collect the coolant and it seems to be the same volume as that lost.

Unfortunately as the overflow pipe does not reach the bottom of the plastic bottle I have to pour the coolant back manually. I will have to fit a longer pipe to see if the coolant will be sucked back as the engine cools.

There is no indication of overheating but just to make sure I have cleaned all the pipes in the heat exchanger. I will however also check the end caps next time I am on board.

As the engine has only done approximately 350 hours a leak at the water pump seems unlikely.

Hope this helps.
 
Genoa said:
i'll have a clser look ot them there caps then, and the pump.
Click to expand...

Be careful. Them there rubber end caps for a Volvo are about £50 a pair..... See my recent post complaining of the price... and no you can't buy equivalents anywhere else cos it's not a Bowman heat exchanger its a Japanese special.....
Seriously though REMOVE both end caps and examine carefully. I took mine off cos I had an obvious seawater leak from one but the other were boogered also. You can't see properly by just tightening em as they deteriorate under the jubilee clips....
 
Some irregularity in water "use" in the closed coolant system seems pretty generic. Theoretically the system is closed and that's that, but in practice, there's variability - I find the same in oil burn. I find there are no ill effects with a low level of "use", after all if the engine is running at a satisfactory temperature, then the gear is doing its job.

If coolant is accumulating outside the engine then time for action, of course.

As others have advised, a good check all round, tighten hose clips a 1/4 turn and remake any connections that seem to be weeping.

A final suggestion: if you are concerned, you might want to look at using one of the proprietary radiator sealant fluids used in car engines. If that has no effect and losses are unacceptable you are facing a strip down!

PWG
 
I had exactly the same problem on a Jeanneau I bought earlier this year same engine. The filler cap was not turned all the way down, it appears to reach a stop but I then discovered looking at the lugs that it would take another quarter turn. :o

Did it and no leakage since. :)

I also thought the face plate on the water pump looked worn so replaced with a Speedseal.
 
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VicS said:
Thats the seawater pump !?
Click to expand...

Yes Sea water pump. Whilst I was checking the front end, having discovered the coolant cap not turned down I slowly started checking everything!!!!

Speedseal is a nice bit of kit.
 
You offering Vic?
Click to expand...
No sorry I dont have the skills ... although I still have my Father's lathe! I'd have a crack at it if I wanted one for myself though.
I mentioned it because I do know someone who simply made one instead of buying one. Exactly what my father would have done!
 
VicS said:
No sorry I dont have the skills ... although I still have my Father's lathe! I'd have a crack at it if I wanted one for myself though.
I mentioned it because I do know someone who simply made one instead of buying one. Exactly what my father would have done!
Click to expand...
I have the skills but not the equipment! Have always lusted after a Myford Super Seven but have enough tools in the garage to get rid of when we go to the Med.
Stu
 
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