2002 Volvo Penta heat exchanger bypass

[christensonwj]

Good morning all. We’ve discovered issues with our heat exchanger (sea water to coolant) on our 1986 Beneteau with a Volvo Penta diesel. We would like to know if a bypass or delete would be warranted considering we only sail in fresh water and could we simply run the fresh lake water directly through the diesel without the exchanger?
Thanks in advance for the responses.
Bill

 

[Rich Stidger]

IMHO, this is not a good idea. The antifreeze/water mix in the engine has a higher boiling point than water alone and also has anti-corrosion properties that are beneficial to the engine. Do it right- fix the heat ex-changer. Maybe you can get a good used HX to mitigate the cost. Check the following supplier at the link below for an OEM replacement. I have bought from them many times for my own Volvo MD22L-B engine. Good people, best prices I have found on the planet.

Parts for Engines (UK) - Perkins and Volvo Penta Engines

 

[kappykaplan]

this is not a good idea. The antifreeze/water mix in the engine has a higher boiling point than water alone and also has anti-corrosion properties that are beneficial to the engine. Do it right- fix the heat ex-changer.

 

[JamesG161]

Fresh vs Salt water is not the key on heat exchange.

On my VP 22MD-L The Hear Ex is easy access, sound like you water pump impeller need Replacing.
I buy all my part where @Rich Stidger linked.

New impeller kit around $25
Jim...

 

[pipedream]

Take a minute. Start at the exhaust elbow and verify raw water traverses the system. four bolts to loosen the exhaust elbow, then loosen the tube coming from the exchanger.

If you have flow, and you see scale plugging the tube at the elbow, you found your problem.

Good luck

 

[Ralph Johnstone]

If you have flow, and you see scale plugging the tube at the elbow, you found your problem.

And if you have scale plugging your HEX tubes, imagine what that lake water will do to your engine coolant passages . Although the lake is fresh water (does not not contain sodium chloride), it could be hard water meaning it contains dissolved salts of calcium and magnesium. This is the material that precipitates out of water to plug small passages.

 

[pipedream]

Actually, the later model 2000 series blocks and heads were made with nickel steel, so block corrosion is not such a problem. The exhaust elbow, on the other hand, is cast iron. I've only got about 500 hours on them before they plug up. The cure is simple and less expensive then a replacement volvo part.

The second photo is a one year old replacement made of cast stainless from a PNW company. Less expensive than original, and i expect it to last well beyond 500 hours.

 

[Ralph Johnstone]

Actually, the later model 2000 series blocks and heads were made with nickel steel, so block corrosion is not such a problem.

Corrosion ? No, in this case it looks like you are experiencing deposition in your HEX rather than corrosion. Totally unrelated problems. I don't think you have the answer as to why your not getting any cooling water through your HEX. I would suggest you do some serious searching while you still have a working engine.