MD2040 Volvo PENTA heat exchanger

[landonshaw]

I once started pounding on an engine block of a MGB only to fine that a support for a hose was a bolt. Luckily I didn't damage anything.

Thanks

[landonshaw]

Still having heat exchanger problems. Now have the engine apart and the system is soaking in vinegar. Doesn't seem to want to come out. Any suggestions?

[jimbunyard]

Let it marinate a bit, but after that, drain it and break out the heat and a hammer.

Since the tube bundle is soldered together, you have a somewhat fine line to toe; you want to heat the cast iron as hot as you can without softening the solder in the HE bundle so when you start hammering you don't mess up the bundle. In my experience, the hottest flame you have access to is the best; the idea is to heat the cast iron evenly first, and then get the bronze bundle moving out before it gets as hot as cast iron housing. Ox-acetylene is best (but keep it moving and remember that the heat flows through the material; after you take the heat away, areas that are further inside will continue to heat until an equilibrium is reached), followed by mapp gas or a propane torch (which may heat too slowly to be any use). Once the temperatures of the two become the same, you have to let everything cool down and start over.

Equally important are the tools you use to drive the bundle out. At first, you can just use a board that covers the entire end of the bundle to drive against, but if the bundle still has to be driven after it enters the heat exchanger, you need to have what is essentially a huge dowel the same diameter as the bundle to spread the force of the impacts equally over the relatively soft end face of the bundle.

Also important is to have the housing solidly held, clamped or wedged so that it cannot move. This ensures that when you start with the hammer all the force is applied to moving the bundle out of the housing and not to bouncing the assembly around or distorting the bundle. Short, sharp blows are best here; we're not busting concrete.

It may be advantageous to try it from both ends, it is possible that it will come our from one side or the other more easily...

[cherikita]

My Volvo 2040 has started leaking green water under the batteries ie nearly a litre Is this from the fresh water coolant system Cant see where it si coming from with the motor running

[landonshaw]

It sounds like antifreeze from the fresh water side. I sometimes use baby diapers in the bilge to get an idea of what part of the engine is leaking. I run the engine and start observing where the diaper gets drips.

[landonshaw]

Jimbunyard, took the heat exchanger out of the vinegar after 4 days and again took a piece of wood across the core. Finally it moves! Moved it back and forth 4 times, rinsed with a hose and put back in the vinegar. Only moves when hitting the wood with a hammer for now. Thanks for the suggestion on the large dowel! I will go to a woodworking shop and have one made. Let it soak again a few days and go at it.

[landonshaw]

I finally got the heat exchanger out. Took it to a shop and the set it in acid then used a press to push the HE out. It looks like the housing needs to be replaced though. A lot of corrosion.
I am testing the Heat exchanger now. I do not have compressor but I do have a leaf blower. Do you think the pressure from the leaf blower would be sufficient? I have tried it and it seems to not be bubbling in the tub of water. No bubbles are visible.

Dave, Aloisius

[landonshaw]

I could also try a foot pump for a dinghy.

[landonshaw]

I found something else. I have dive tanks so I hooked the heat exchanger up to the dive tank off of a 35 Bar or 500 PSI line and pressurized. The heat exchanger does not leak. Interesting that the dowel that I stuck in a hole, the pressure is enough to force air up through the wood capillaries and out the top, the end of the dowel is bubbling but not the HE.

[FULLCIRCLE331]

If you have two long pipe clamp you can use them to press out the unit. Press a dowel the proper size in one end.

[Cadence]

Originally Posted by landonshaw

I found something else. I have dive tanks so I hooked the heat exchanger up to the dive tank off of a 35 Bar or 500 PSI line and pressurized. The heat exchanger does not leak. Interesting that the dowel that I stuck in a hole, the pressure is enough to force air up through the wood capillaries and out the top, the end of the dowel is bubbling but not the HE.

If the HE does not bubble at 500PSI I guess it does not leak. I would be afraid of that much pressure. I thing you gave it the "acid test". I'm glad for the positive outcome.

[landonshaw]

Finally finished the project. Boat ran fine in Sunday, planned to do a sea trial today but too much wind, don't want to break something else. Ran for two hours and no leaks. Turned out that the heat exchanger was fine. The housing was the problem, $1,900US. also when taking it off I broke two studs so had to take the head off also. Parts came to around $3,000. I have the boat back though.
Thanks for all the help. The dowel was get to press the heat exchanger out and not ruin it. The machine shop liked that.

[chowdan]

Originally Posted by landonshaw

Finally finished the project. Boat ran fine in Sunday, planned to do a sea trial today but too much wind, don't want to break something else. Ran for two hours and no leaks. Turned out that the heat exchanger was fine. The housing was the problem, $1,900US. also when taking it off I broke two studs so had to take the head off also. Parts came to around $3,000. I have the boat back though.
Thanks for all the help. The dowel was get to press the heat exchanger out and not ruin it. The machine shop liked that.

Just as a FYI, I own a Perkins M20, which is the same as the Volvo MD2020. I believe the Perkins M30 is the same as the MD2030. When i was trying to determine if the M20 should be rebuilt I noticed that some of the MD2020 parts were cheaper while the vast majority of the M20 parts were cheaper.

For future reference, I'd recommend searching between both brands to get your parts for the cheapest part(or finding the agriculture version for parts that are none marine related)

[Howard293]

Originally Posted by landonshaw

I have the work shop Manuel by Volvo and to remove the heat exchanger seems relatively simple. Anyone have experience?

Out today, no wind so ran the engine. Water alarm went off in bilge and it looks like my raw water that goes thru the engine for cooling is getting into the coolant side. I suspect the heat exchanger is the problem. Any other ideas, possibilities?


Sent from my iPad using Cruisers Sailing Forum

Hi. Did you discover the problem with your engine as I'm having the same issue with mine?

[FULLCIRCLE331]

I have had the heat exchanger apart looking for missing impeller blades. Only found two out of three. It came apart easily. Had trouble getting it back together. Used a long pipe clamp to-push the rubber boots in place until I could tighten the clamps.
This is a poor design, only the clamps keep th raw water and coolants separate. If a clamp gets loose they can mix. Look at all of the clamps and the rubber boots for your problem.

I have installed a filter after the raw water pump to catch blades if they break off. This has saved me hours looking for missing blades.