Heat exchanger help please?

[robp]

Anyone with Volvo experience?
Engine sump bay under my MD2040 started filling with water on Saturday. (Well it didn't start - it filled and overfilled and started on any other route it could find)! I got the boat into shallow water and concluded that the cutlass bearing was ok. An engineer looked at it and is fairly certain that the heat exchanger is corroded. This then of course pushes sea water into the fresh water header and comes out of the overflow. Last year I had a gaiter replaced for the same problem. On reflection I feel that it might just be that the gaiter is not sealed well enough. Anyway having got the exchanger out I'm having it pressure tested to check. Question is, when I (hopefully) re-fit it, do I simply locate it in the gaiters at both ends or should I use some waterproof grease around the inside of the gaiters? Also, there is a large hole toward each end in the curved surface of the cylinder. I didn't see the location of these on removal. I'm not near the boat now but do they locate opposite hose inlets/outlets?
Any advice gratefully received.

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[Ruffles]

Rob,

Get the heat exchanger checked at a car radiator shop. If the tubes have rotted they can replace them for peanuts - you don't need to buy a new Volvo part. The tubes are simply soldered in. Try Wessex Radiators near the Hamble.

But. If the water is leaking around the gaiters on the inlet side it is more likely due to a blockage. Does the inlet gaiter balloon out when you rev the engine? If the tubes in the heat exchanger element are reasonably clear then you may have a corroded exhaust manifold. I had this on my 2030. Wessex radiators acid dipped it for me to try and clear it but in the end I had to buy a new one. Fairly pricey but then it is a complex casting.

Rob.

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[robp]

Thanks Rob for the information. I took it to Abbey Heat Transfer. They will clean it and pressure check it. When you re-fitted yours did you just put it directly into the gaiters? Did you fit it any particular way round? I guess the 2030 is similar to the 2040. Engineer mentioned £600 for a new one - ouch! Although it is only 6 years and 800 hours old..

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[Janger]

Would you be interested in a new heat exchanger? I have one that has probably run for less than 50 hours from my old 2030. I advertised it last year with other bits from my old engine, it cost me nearly £600. I sure a deal could be done should you be decide to replace yours. It is still in Volvo bag nice and clean etc.

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[Heckler]

It never cease to amaze me when "engineers" pronounce and everyone believes em.
the heat exchangers on the 20X0 engines are that simple that a child can look at them and tell you whether they are shagged or not. first of all realise that the rubber boots at both ends need to seal on to the exchanger by tightening the jubilee clip tight, and the smaller jubilee clip must be tight to seal on to the casting. if they do not grip well or are misplaced then sea water will enter the fresh water side. there is no mystery about them gripping, clean castings, NO GREASE, clean exchanger, good jubilee clips and tight. exchanger hold to light and look thru tubes, are they all clear? to roughly test them get a bike pump and pump one end and thumb on other end, use a bit of inginuity.
could you see water coming out of the engine? if so, from where?
pm if you need any more help
stu

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[robp]

Well he is a well known marine engineer who I've known for years. Anyway I'd never even seen a heat exchanger before, so having pulled it to bits, I thought I would have it checked although I'm learning fast and thought it looked ok. It has tested ok too, so I'm now convinced that the gaiter was not sealed well enough. It was just the question about sealing surfaces and which way round do these flippin holes go?? I still don't know.

Thanks for your help.
Rob

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[robp]

Thanks for the offer. It has tested ok, so no sale I'm afraid.

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[Ruffles]

Rob,

Does the manifold seem restricted when you blow into the water inlet? I was unsure so I took it to my local Volvo dealer (RK Marine) and they very kindly let me compare it with a new part. The difference was obvious. Also, loosen the rubber boot connection to the manifold with the engine running. Water will spurt out of here but should stop coming out of the overflow. Proves that the blockage is after the heat exchanger.

Apparently you are supposed to drain the salt water out of the manifold over winter. Does anyone do that??

The owners manual tells you which way up to insert the element. I suspect that the large holes are at the bottom but I can't remeber. There is also a pinhole at the top to avoid an air lock.

Rob.


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[robp]

Rob

I've not tried blowing through it. Thinking that is was leaks rather than blockages. I'll check that, though I'm fairly convinced now that the boot was loose. No I've never drained it down. Maybe I'll try and flush it through whilst I'm at it.

I've been trying to find my owners manual but not really thinking it would be in there.There maybe a French one on the boat. I expect the pictures are the same!

That's helpful, thanks again.
Rob

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[Heckler]

rob
holes face up a sfar as i remember although i dont think its really that crucial because the water can go around the outside of the exchanger to them.
i had mine apart last winter to check everything, had to change the exhaust elbow cause it was nearly blocked, also changed the thermostat in the fresh water pump. keep asking if you need any more info, the engine manual is what is needed if you require drawings etc cause its all volvo penta.
stu



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[robp]

Stu
Sorry, missed this answer the other day. Thanks for the info, I assembled it with holes roughly facing hose inlets/outlets. All seems fine at the moment. I'm really wondering now if it was a wild Goose chase, But you did say that! It was probably just loose.

Rob

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