Knock-on effects of heat exchanger/manifold corrosion

[havasupai]

The D2 55 VP engine in my 2003 B44 has been diagnosed with quite severe and evidently irreparable corrosion to both faces of the joint 'twixt the two.
The boatyard in France is quoting me upwards of 5600? to fix the problem. The engine has done 14 seasons of averagely busy charter and I sailed her (well motored, this being east to west in the Med) form Marmaris to Cap d'Agde this past summer.
I don't think the problem (of exhaust gases and soot all over the engine compartment, and some lack of circulating water) was prevalent for any length of time - one can tell from the exhaust note when its not pumping water in and out.
But I would love the opinion of others as to:

What consequential damage might be expected.
What further problems should one be prepared for with a 14 year old engine with a fair few hours under its belt, and
When do you bite the bullet and replace the whole unit, which at current exchange rates would probably cost twice as much as the repair. But then you have peace of mind, an guarantee and potentially a higher resale value.

Either way it's going to be an expensive winter!

[Craig]

What is corroded?

It is common for the exhaust elbow ( where the exhaust gases met the salt water coolant) to corrode. This should be replaced for about 500 euros.

Obviously, more than that part is corroded.

Craig
"Shirley Valentine"
Gold Coast
Australia

[Yngmar]

That sounds like a price for a repair with original Volvo parts (i.e. an entirely new manicooler - priced around 3200 EUR inc. tax from Volvo dealers). There are other options, including finding a used one or finding a skilled TIG welder to repair it. Someone has done this procedure and documented it with lots of photos for a Volvo MD22 engine (the predecessor of the D2-55 on Bavarias), which while being a different engine design has a similar manicooler: http://www.diecyde.com/index.php?page=volvo-penta-md22-overhaul

If those options aren't for you, I'd seriously consider a new engine for the reason you've already mentioned, especially if it had a hard life (likely if it was chartered, where they're often run for power generation). Another consideration is how soon you want to continue sailing again!

If you do go for getting it repaired, have it thoroughly inspected and sort out whatever is found. The exhaust elbow usually goes first (a mix of blockage, corrosion and weakened metal), although after this time it may already have been replaced once or twice. Coolant hoses can get porous, and make sure the leaking manicooler did not let get a lot of seawater in the coolant channels, which can lead to corrosion or blockage (if you have lots of crumbly bits settling in the bottom of the old coolant upon draining it, that's a bad sign). If it eats oil or smokes heavily, consider a full rebuild, but that only makes sense if you can find an experienced engineer who doesn't charge the usual marine rates, else you're quickly in the price realm of a new engine.

Good luck! 

[blue-max]

I had this problem with corrosion of the heat exchanger. At first thought it was exhaust elbow gasket but after removal it was obvious it was the he. Replacement part in UK £2400. Could not find any used examples ( not surprising) so opted for a repair. Cost £900 and took 6 weeks. engine did not suffer damage from water or smoke ingress - through air filter blocked - its working fine now.