Diagnosing a burst heat exchanger tube MD2030

[KAM]

I was just wondering the best way to diagnose if a heat exchanger tube had burst on an MD 2030 without dismantling although it does look a very simple system.. It's difficult to see if there would be any noticeable effect on the engine. Trying to help a friend a long distance away. Any help appreciated.

 

[RichardS]

Surely if an H/E tube has ruptured the coolant level will drop when the coolant system become pressurised at engine running temperature depending upon the size of the rupture. Eventually the engine will start to overheat,

Richard

 

[dragoon]

The only way you’ll know for sure is to pull the exchanger and have it tested.

However if you suspect you have an issue here, a more likely path of leak is across the end caps either being worn or not fitted properly.

Is your friend losing or gaining coolant?

 

[gregcope]

I would expect to lose collant each time the engine is run and that level might drop or raw water might mix with coolant.

However a more common problem is the rubber end boots leaking which would give the same symptoms.

Has the owner tried to tighten the boots?

 

[VicS]

I agree.
Check the end caps, in particular the smaller of the two large clips at each end. I'd think a leak there is more likely than a holed tube.
If it is necessary to inspect the tubes I think the best way will in fact be to remove the end caps and then the tube nest.

 

[KAM]

Trying to unravel a chain of events first use of the season. Engine overheated. Water reported spraying from coolant filler cap. Bilge appears to have been filled twice. I suspect it was a simple matter that the coolant cap wasnt on correctly but there shouldn't have been enough water to fill the bilge. Engine is now running OK small drip from the rear heat exchanger rubber seal but again not enough to fill the bilge in a short time. It's possible when the engine was hot a much larger volume of sea wster was leaking from the boot but seems unlikely. Its a long keel with a deep bilge. I suspect there is also an unrelated leak somewhere. Thanks for the advice so far. Investigation continues this evening. Any other suggestions much appreciated.

 

[Ammonite]

Personally I would want to check out the exhaust elbow in addition to stripping and cleaning the heat exchanger, checking the end caps etc. Theres a chance the water injection point has rusted up in the off season and the additional back pressure has caused the end cap to fail leading to a loss of coolant into the salt water side, which in turn results in the engine overheating, dumping the remaining coolant into the bilge.

 

[Solwaycruiser]

Had a burst tube on a 2003 once. When engine was running at higher revs pressure was greatest in the raw side and so water went from raw to fresh side and resulted in excess water overfilling that and dumping into bilge. At other times at low revs or perhaps when stopped it went the other way. just one possibility.