Salt water flood - Volvo Penta 2030

[belizesailor]

Originally Posted by colemj

It couldn't have come from the cold side running down a hot engine? The one boot seal problem we had was actually on the intake boot.

Mark

Possiblity I suppose, I never did isolate the external leak for sure.

Could have aslo been the scenario described by Kashmir Cat above, which would have left no obvious external signs on the engine since my coolant over flow hose discharges to the sump under the engine.

[colemj]

Originally Posted by belizesailor

Possiblity I suppose, I never did isolate the external leak for sure.

Could have aslo been the scenario described by Kashmir Cat above, which would have left no obvious external signs on the engine since my coolant over flow hose discharges to the sump under the engine.

Oops, I think we were not talking about the same things! I was directing all of my comments towards the OP's problem, not questioning yours!

Mark

[belizesailor]

Originally Posted by colemj

Oops, I think we were not talking about the same things! I was directing all of my comments towards the OP's problem, not questioning yours!

Mark

Well the (cooling) water got a little muddied between the two I think. All good info on this thread though for a somewhat obscure problem.

FYI: I was recently going to add one of those damn little cuffs to my spares kit (at $60 a pop!) and discovered they are back ordered until at least June 30 (same for several Volvo distributors). Proprietary and poor availability to boot. And if one fails it would be a bitch to jury rig. I like Beta Marines design much better....just good old standard hose fittings.

[Tipsea Again]

Thanks to everyone who offered suggestions. I removed and cleaned the heat exchanger, flushed the cooling system and refilled - all seemed well until the second flood!
While buying a new rubber boot (due to minor damage, not part of the main problem) I spoke to a Volvo engineer, who pointed me in the right direction - the exhaust elbow, where the sea water drops into the exhaust downstream of the heat exchanger, gets blocked with soot, calcium and rust. This causes back pressure which unseats the downstream boot, letting sea water into the 'closed' circuit. This then escapes through the overflow on the filler.

We got home by fitting a long plastic hose on to the overflow and directing the warm seawater overboard.

On stripping down I found that the 20 ID boss on the ex. elbow was reduced to about 3 ID. All now sorted.

Check that elbow when next stripping down!

Martin is my name, Tipsea Again is my boat.

[DeepFrz]

Thanks for posting the solution to your problem. I never would have guessed that a little back pressure would have caused that.

[Tipsea Again]

Salt water flood - Volvo Penta 2030
Following your suggestions I stripped, flushed refitted the heat exchanger and rubber boots. Next time out the problem recurred. I called out a mechanic on Sunday, who diagnosed failure of the heat exchanger. I got home with a plastic hose taking the water from the radiator filler overflow overboard.
Stripped out the heat exchanger, fitted the rubber boots with a wine cork in the downstream outlet, and tested (at lung pressure) under water. Heat exchanger OK, tiny leak in the downstream rubber boot, damaged by the jubilee clip. Not the main problem.
At the Volvo agent, buying a new boot, a young engineer overheard my comments and suggested that I should look at the exhaust elbow, where the raw water drops into the exhaust. Sure enough this was blocked with soot, calcium and rust, causing enough back pressure to unseat the boot from the heat exchanger sending raw water into the 'closed' cooling circuit.
I note from other threads on this forum that there are stainless exhaust elbows available to eliminate this problem.
Safe sailing
Martin is my name and Tipsea Again is my boat.