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Sea Scouter

I really need some help with Volvo Penta MD2003 overheat.

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MD2003, fresh water (closed system)

Tendency to overheat at idle or low R's after about 15 minutes, might not overheat when running >2000 rpm

 

I thought I was handy when...

I flushed the freshwater system... removed gel jizz out of bottom block drain. Flushed 3 times until clear. Refilled with the silicate free stuff.

Nope

R & R heat exchanger with boil out at the hot rod shop

Nope

Changed thermostat

Nope

Ran without thermostat

Nope

Rebuilt fresh water coolant pump. Might have had an air leak

Nope

Flushed again.

Nope

 

PLENTY of raw sea water flow. Engine runs just about as it always has.

 

I need some ideas.

Thank you in advance.

 

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I'm likin' the head gasket...

No evidence of juice in the exhaust but I'll check for bubbling in the reservoir.

It's not a terrible job to pull the head.

Thanks

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I have had the same motor in my previous boat, we inspected the boat prior to buying.....the owner did a great job of hiding the motor over heat problem.

So.....on the short trip to deliver the boat we had an cloud of steam.....not your same problem but the solution may intrest you.

 

The mechanic talked me through some of the problems .

The water pump rotor would break down every time the motor was run, eventually not pumping water....check this, replace and observe, feel water temp out of exhaust.

The head in my boat was corroded , he even told me about not using different coolants and that the coolant should be changed out every 24 months.

.....I had to replace the head, and lots of the rubber seals.

I found a site that had some good info....google the problem using the motor name and brand......find a good mechanic.

 

After the fix, the motor ran like a charm and served us well. Hope this helps

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Wrong impellor fitted probarly the fresh water one.

Only explains overheat with little water circulating at low revs.

look for obstruction but not blockage in fresh water system otherwise

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A few clarifications...

 

Really two systems, right? Fresh water is really the closed coolant system runing the ethylene glycol stuff. The orther system is the raw water system pumping cool water from the big lake.

 

The closed side pump was inspected and the impeller was in good shape and the 'shells regasketed and sealed with RTV. It's a big inpeller... larger than an automotive type. It is original from 1986.

The raw water impeller has been replaced. PLENTY of water coming out of exhaust.

 

Boat has been in fresh water for it's entire lifetime. I dd notice some silica goo on my first flushing.

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Sounds like you have had fun.....did you do the google thing, you will find your problem in various forms is covered ....have alook.

 

Did you put the heat exchanger back properly with the right gaskets and make sure it was aligned, did you check the exhaust fitting on the engine.

 

Find a mechanic......a good one

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MD2003, fresh water (closed system)

Tendency to overheat at idle or low R's after about 15 minutes, might not overheat when running >2000 rpm

 

I thought I was handy when...

I flushed the freshwater system... removed gel jizz out of bottom block drain. Flushed 3 times until clear. Refilled with the silicate free stuff.

Nope

R & R heat exchanger with boil out at the hot rod shop

Nope

Changed thermostat

Nope

Ran without thermostat

Nope

Rebuilt fresh water coolant pump. Might have had an air leak

Nope

Flushed again.

Nope

 

PLENTY of raw sea water flow. Engine runs just about as it always has.

 

I need some ideas.

Thank you in advance.

 

I did all of that, then pulled off the exchanger housing/exhaust manifold. There was a clot of corrosion immediately behind, or in front of the thermostat. You couldn't see it with the coolant pump removed. The clue was using an IR heat gun. The exchanger was running at sea water temp because coolant couldn't circulate through the exchanger, yet the head temp was 215.

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Had the same problem on a saltwater raw water cooled 2003.

 

There was a plug of scale blocking every one of the connections between the coolant pipes and the engine.

 

May not be an issue on a FWC motor, but I suspect there is a lot of turbulence in those joints between the copper pipes and the block, the ones with the crappy half moon clamps.

 

Was easy enough to take them apart and clean them, there was no scale to speak of inside the block and head.

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check your hose routing

 

A friend of mine bought a used boat this spring that the previous owner had over heating problems over the years. He even installed a larger heat ex changer.

 

Somewhere along the years the hoses containg antifreeze got re routed and zip tied to the overhead above the engine. Made for a tidier look in the engine room but it put a air bubble in the line that got sucked into the centrifical water pump. Well centrifical pumps don't work well with air and it stopped circulating when the air bubble got in the pump. Previous owner made system work by adding extra hose to the filler and adding antfreeze from two feet above which was enough to make the air bubble pass.. Any ways new owner rerouted hoses to normal elevations and all is working fine and no need to prime from up high. Check the routeing of the hoses they need to be at the right level to prevent an air lock///

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I was on vacation, and now I'm back.

Next stop will be the IR gun and find out what is really running hot.

To all those who suggested checking the goofy rubber washer gasket connector things, yes, those have ALL been replaced. Do you know that Volvo gets 4 or 5 bucks for those little square rubber washers?

At that time I also poked around in those passages in the block. Best I can tell you is that that the block appears to be more clean than some the of pots and pans in my kitchen.

I think I will also pull the temperature sending unit and test. Don't know how yet but the googles might have some spec for R when sending unit is hot vs. cold. And yes, I have googled the hell out of this problem.

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What is telling you have high temps? Maybe you have a bad gauge or sending unit.

Get a IR gun and check the temp that way.

 

VP has a temperature alarm and a sending unit on engines with the "delux" instrument panel. Are you getting both a buzzer and a high reading? I think the factory sender is 10-180 ohm if memory serves. I swapped my original VDO gauges out for Teleflex. Had to change the oil pressure sender but the temp one was the same.

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What is telling you have high temps? Maybe you have a bad gauge or sending unit.

Get a IR gun and check the temp that way.

VP has a temperature alarm and a sending unit on engines with the "delux" instrument panel. Are you getting both a buzzer and a high reading? I think the factory sender is 10-180 ohm if memory serves. I swapped my original VDO gauges out for Teleflex. Had to change the oil pressure sender but the temp one was the same.

My thoughts as well......is there steam !!.....if not how do you know it's hot ??

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Ran the IR gun and had to stare at the cooling system schema for a while. Here's what... Coolant n3ever really makes it back to the heat exchanger. A decade ago I had a leaky hot water heater and pulled it. In anticipation of replacement I ran a hairpin of 1/2" radiator hose up to the port settee. So, from the coolant pump, to the setee and back to the pump is the first route of the hot coolant. Except it was trapped in a kink and not returning to the pump for it's trip to the heat exchanger.

Thanks to all and the IR gun is also good on cats!

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Turns out that I already shortened the hairpin maybe a few years ago. So that's not it. Shit.

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If you haven't done this yet you need to inspect/replace any multi-ply cord reinforced hose in the system. The inner wall can collapse causing a flow restriction at low rpm//pump pressure. As rpm increases it opens back up. This problem baffled me once to the point I couldn't in good conscience charge the man the amount of time I spent scratching my noodle.

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10142.jpg

 

Start taking it apart. Thermostat first, hoses (there aren't many rubber ones here anyway), heat exchanger and then waterpump. I recall hearing somewhere that the aluminum impeller in the waterpump used on these can crumble apart after years (electrolysis or something?)

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No not many hoses except OP also has a run going to a future water heater. And there's still the raw water side.

 

10142.jpg

 

Start taking it apart. Thermostat first, hoses (there aren't many rubber ones here anyway), heat exchanger and then waterpump. I recall hearing somewhere that the aluminum impeller in the waterpump used on these can crumble apart after years (electrolysis or something?)

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No not many hoses except OP also has a run going to a future water heater. And there's still the raw water side.

 

If it is plumbed properly this should not matter. Line should run from the water pump (Part #8 on the diagram) to a plug on the cylinder head near the thermostat. Flow can be on or off, and the cooling circuit will function the same. I ran a hydronic cabin heater for years like this off my engine with a ball valve inline to adjust heat output. The engine didn't care if the heater was full on or off.

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It's an easy fix. Take the raw water hose, and plumb it to the raw water pump on a Yanmar. When the Yanmar is finished with it, you can run it through your Volvo and it will keep it warm.

 

You're welcome.

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The Yanmar is the best suggestion yet. God has a Yanmar in his old yawl.

On a more serious note, I'm going to block off the hose at '8' where the hairpin is presently.

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I hate this engine so bad. It does not return the love and tenderness that I have shown it over the years. I am back in that bitch it today.

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I don't understand why anybody puts a Volvo in a boat. Their parts prices are so insane that they are the stuff of legend. Just read a story of a guy in Britain who needed a new heat exchanger for a small Volvo 4 cyl. diesel - it was 2700 pounds ($4300 US) - for a small heat exchanger!

 

He had one custom made for about 10% of that price.

 

Do they sell the crate engines cheap to get you hooked or something?

 

To me, a Volvo in a boat would be a deal killer.

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Really?

Do you think I went back in time and convinced the first owner to get a Volvo knowing that I would seek a frustrating challenge a few decades later?

Volvo ignition key switch.....$240.00. Borg Warner....$18.00.

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Really?

Do you think I went back in time and convinced the first owner to get a Volvo knowing that I would seek a frustrating challenge a few decades later?

Volvo ignition key switch.....$240.00. Borg Warner....$18.00.

 

I think you missed my point. I've seen & heard so many stories & experiences like yours that;

 

To me, a Volvo in a boat would be a deal killer.

 

I wouldn't have bought the boat in the first place unless it needed a new engine and was priced accordingly.

 

Sorry I can't offer any advice to fix you up but you do have my sympathy FWIW. ;)

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Hi,

 

Don't despair (it doesn't help).

 

MD2003 is not FWC as such, the FWC has to be added. Do you know when it was mounted?

 

Did you state that the boat has always been on lakes and similar - then there was not an urgent need to add the FWC from beginning, maybe? If the engine was without FWC for some years that may have resulted in salts etc builing up inside in the now freshwater system.

 

In any case, the most likey source to the overheating issue is somewhat narrow cooling channels on the freshwater side (I have read that you have been running some solution, it may take some, but probably not all. In my experience ...mechanical removing is best). Consider to do some tests on the freshwater flow, or dismounting heat exchanger etc.

 

Far from being a VP fan, in spite of living in Volvo-land, but the 2003 is not bad. Much more modern than the comparable Yanmar 3GM30F (which I have now, no problem ... reliable and so on, but old design).

 

Best of luck

 

J

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From the schematic, no it is not turbo ... The turbo-like thingy is the coolant pump.

 

However ...

 

We're it turbo, there is a coolant line from the turbo to the t/stay housing that T's to the HX. Inside that line, between the turbo and the T is a plug with an orifice. This plug can become dislodged and plug the T causing overheating. To fix, remove the line, remove the plug, slightly - really slightly - crimp the line between the turbo and T nearest the T and reinstall the plug, then the line.

 

Best of luck.

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Solved///

 

TAG: Volvo Penta 2003, overheat problem, heat exchanger

 

 

When I reassembled the heat exchanger, I rotated the inlet plate (part 27 & 28) 180 degrees. That caused the engine coolant (closed side) to take a very short path in and out of the heat exchanger, just a tiny 'u' of flow. When rotated to the correct position, the engine coolant is forced through a labyrinth of baffles (double pass) running parallel with the tube bundle, i.e., the big long 'U'. Remarkably, the solid piping lines up pretty well even if the end plate was rotated out of position.

 

From start to finish

Engine overheated in idle.

Flushed engine and had the HE dipped.

Engine flush returned silicated snot out of bottom drain

HE did not really need to be removed but... in for a dime, in for a dollar.

Reassembled HE incorrectly

1 year of misery

Rotate inlet/outlet end plate.

Engine runs at 170 degrees and holds.

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thanks for the final note - too often no one comes back with what they found to be the euraka moment and the solution to their problem!

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