loosing green cooling water on Volvo D2-55

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alex33

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I have this sailboat+engine since anew in 2006, 900 hours,private use,strict mentenace proceedures, etc.
A month ago it , while going above 1500RPM, it started forcing green water out to the bilge via the small plastic tube fitted at neck to . Temp gauge show normal. No water in oil. I put a collecting bottle under that tube so fresh cooling water can be monitored. in further occasions I noticed that normal green color unchanged, and after shuting down engine and cooled down for half an hour or so, all coolant is sucked back from the bottle( open to air ) to the cooler. carefull mesurments after few such cycles show no coolant is lost ,all is sucked back and no residue or change of color of green water..and engine oil is noticed.
when once motored to 1800-2000 RPM, just regular RPM , for half an hour or so, one liter of green water was forced out !! and still temp gauge show rifght normal temp, no change in sound, no fumes, no drop in engine power, etc..
There is no change in exhausted water or gases, no steam, same raw water quatity going out, no leaking fluids noticed at engine block , around , or else.
Till then there was no water expeled this way or any for all these years, except maybe few drops when overworked temporary, even when motoring at 2000-2200 rpm for 24 hours while cruising Med.
I also notice now on that coolant droplets on the plastic tube seen from outside, that even when water going out ceased when lowering rpm after such occurence, there is movement of water droplets that might indicate air or gas of sort is still forced out this way, probably under pressure..
but no combustion fume smell noticed in engine compartment.
Filler cap was replaced with new original one, in case it is faulty and let water out at lower than normal presure ( 0.95 pka) but the problem persist.
this is not the issue.
Before messing with the expensive head gasket replacemet issue, what else can cause the problem ? what other- hopefully simple - tests/check can I do to diagnose the problem ?
Many thanks, Alex
 
DON'T take this as gospel, 'cos there are much more knowledgeable folks on here than myself, but might be worthwhile checking thermostat if fitted and if as you say the coolant is drawn back in as the engine cools, a temporary solution might be to fit a header tank (I think that's what they're called) with a pressure cap similar to those fitted in a car. Heat exchanger matrix all clean? Did mine a month back and what a difference to running temp. As I say, there will be others along later to offer (no doubt!!) more exact and accurate (ie model specific) advice. I guess they're all out sailing...............
 
First check is that the engine isnt overfilled in the first place. Your car has a bottle just like the one you describe and it functions in just the way you describe. Your engine, if its like my Volvo 2030 doesnt have a bottle but instead has an air space over the top of the water in the heat exchanger to allow expansion. Check what the manual says. Are you absolutely sure you have the right filler cap?

The other possibility is localised boiling which generates steam forcing cooling water out of the system and then suckjing it back as the steam condenses. Maybe the raw water pump has failed or the heat exchanger clogged up.

Its unlikely to be a head gasket. If it were and there was combustion gas getting into the cooling system, you wouldnt get the green water sucked back in. It's easy enough to check anyway - many garages have sniffers which can detect combustion gas in the water system.

Equally you would easily see oil in the cooling system and you would be losing cooling water into the oil.
 
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My Beta also expels coolant.Never a lot only half a cupfull everytime it runs.Beta advised me to fit an expansion tank and block the pipe for the coolant overflow.
 
I agree be sure you are not overfilling the system.

There is a kit for a simple bulkhead mounted expansion tank so this may be a known characteristic.

Provided water is not continuously ejected, just the same fixed amount every time, I don't believe you have a problem. You could probably simply run with that much less in the system.

You could make your collection bottle a permanent feature . I did it once to a car that tended to do the same thing.

You could fit the expansion tank kit. It's 164 Euro

http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744440-26-7505.aspx

.
 
Actually, at regular RPM, water is pushed out continuously at an alarming rate that will eventually cause overheating after an hour or so. I went along enough time to notice this ..unless I just lower rpm to qute low, 1200-1400 RPM ,so no too much water would be pushed out. This is definitely nothing close to normal situation..and it didn't happen all these years..
Double checked the filler cap, it is the right one and OK.
What other checks can be done?
 
Do you have a calorifier ( water heater) fitted? If so, it may need air bleeding out of the system.
 
I have a calorifer fitted..

It works well,heats water quickly and efficiently, what it has to do with loosing green water?
 
Sorry misunderstood the symptoms.

If running long enough then an unknown, but large, volume of water is ejected, but when the engine cools it is all drwn back into the system from your overflow bottle.

the fact that it is all drawn back I think rules out a heat exchanger leak resulting in coolant being replaced by raw water.

Possibilities I think are:
A big air lock, or a least a pocket of air trapped somewhere, that expands as it heats up, forces the water out, but then contracts and draws the water back in once it cools.

Overheating locally.

Maybe a head gasket leak between a cylinder and the water jacket. That would not result in oil in the water nor water in the oil but you'd expect to notice some rough running, at least at idle speed.
However I don't think the water would be drawn back in, not entirely anyway when it cools.​

Start by venting any air ... but I don't see any air vents in the drawings.
As Northup suggests vent any air from the engine coolant side of the calorifier. That may mean by loosening a coolant hose at the highest point.
I don't know any thing about the calorifier as such ... it's not shown on the engine drawings... but a load of air trapped there could well be the cause.
 
alex33 said:
Actually, at regular RPM, water is pushed out continuously at an alarming rate that will eventually cause overheating after an hour or so. I went along enough time to notice this ..unless I just lower rpm to qute low, 1200-1400 RPM ,so no too much water would be pushed out. This is definitely nothing close to normal situation..and it didn't happen all these years..
Double checked the filler cap, it is the right one and OK.
What other checks can be done?
Click to expand...

The key bits of information are 1/ that it always sucks all the water back again and doesnt lose any and 2/ that it never used to do this.

If you are absolutely sure of 1/ I dont see how it can be a head gasket problem. You would lose water if there were a head gasket break . Nor would it suck everything back. If 2/ it never did this before then it cant be a harmless characteristic of the engine just requiring a header tank installing.

To my mind the only feasible scenario is localised boiling which creates steam, forces out water under pressure but then sucks it back in as the steam condenses. So the obvious things to check are the belt driving the engine water pump if it has a belt, and the thermostat to see if its jammed, and the hoses to see if any have collapsed.
 
If overheating were the cause I think you would see some indication on the temperature gauge or you would get the overheat alarm .. or both!

While not ruling out overheating I would go for the air in the system as suggested by "northup" first.

Easy enough though to check the pump drive belt at the same time. It should be possible to deflect the belt by 10mm using "normal " thumb pressure between the pump pulley and the alternator.

If you have to go as far as testing the thermostat then it should start to open at 82C ±2C and be fully open at 95C (but check with your owners manual as there may be some variation with different versions of the engine)
 
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When I had the same problem with a VP D3 it turned out to be a air lock.
Drained system down keeping coolant. On refilling system opened all drain cocks and closed as soon as coolant started to run out.
This fortunately cured my overflowing expansion bottle
 
Thanks guy for the advice, I will look into these..

water related issue. I was told there is a presure check for cooler when engine not running. A good thing since it will eliminate problem caused by expanding trapped air in cooler. I is done by pumping in air under presure into cooler and check if and how fast the presure drops, this to show possible leaks. will this show a probable faulty head gasket or it may leak presure due to other reasons and ways as well?
I have to say the there are no exterior leaking signs of any kind from the cooler, engine block, water pums, hoses. etc.
All dry as new.
Regarding installing expansion tank kit, it is an option but not required in the original instalation. A sister boat with exactelly the same engine/model/year but twice the engine hours has no problem without it. As far as I know , the expansion tanks also have a pressure valve..so under excesive pressure, water will pour out from that place in expansion tank instead the valve+ tube to air as it is now..
Many thanks to all contribuiters, Alex
 
our D2-55 installed in a Bav has a header tank and there is quite a bit of change in the coolant level from hot to cold. We have had some expelled after an engine service because of over filling.

We had intermittent overheating after a raw water impellor was changed but this turned out to be an air leak somewhere in the inlet side of the raw water circuit. You can tell its a raw water problem because the water ejected with the exhaust gets steamy and sometimes stops for a short time with a corresponding change in exhaust note.
 
VicS said:
If overheating were the cause I think you would see some indication on the temperature gauge or you would get the overheat alarm .. or both!
Click to expand...

Not necessarily - depends on the location of the temperature sensor. But its likely either air lock or local overheating. Cant see what else it can be assuming the OP's description is accurate..
 
My experience of air locks, in automotive and marine engines, is that the first thing they affect is any external equipment, like heaters and calorifiers. The OP has said his calorifier works fine, which suggests that an airlock is not responsible for the problem. It sounds like simple over-filling to me. If there is no ullage in the header tank, or whatever method is used for filling the water side, it blows out through the filler cap relief, although the exact location of the plastic tube is unclear from the original description.
 
It sounds like simple over-filling to me
Click to expand...
I thought that which is why I suggested just running with that much less water in the system but we were told that it is not just a definite amount that is ejected but that it keeps on spewing water out. Also that this is a recent problem
 
Green water ejection (not on St. Patrick's Day?)

Are there rubber ends on the heat exchanger? two sets of double clips on each?

These need to be tightened bi-annually, or at least checked. If they are loose, raw water can be injected under pressure into the coolant and may seal again when the engine cools down.
I has happened to me, easy fix, screwdriver!! Green water was ejected when this happened, so there must be enough pressure generated by the raw water pump to make this happen or else I am having false memory symptoms again!

Good sailing and boating to all,
 
If they are loose, raw water can be injected under pressure into the coolant and may seal again when the engine cools down.
Click to expand...
But the expelled coolant wont be drawn back in when the engine cools, it will simply have been replaced by sea water.

There has to be a void left of heated air or steam for all the expelled coolant to be drawn back in when it cools.
 
paulclan said:
Are there rubber ends on the heat exchanger? two sets of double clips on each?

If they are loose, raw water can be injected under pressure into the coolant and may seal again when the engine cools down.
Click to expand...

Sorry, can't happen in this way. The coolant will be under pressure, something like 4 - 13 psi above atmospheric (unless the pressure cap is faulty!) The raw water is pretty much open-ended at the exhaust manifold, no more than 1-2 psi probably. So any leak will go the opposite way, which clearly does not happen in this case.

As I said earlier I don't believe this to be an air-lock problem. One other possibility is that a small amount of steam is being created, maybe a partially blocked water passage in the head? Steam condenses when the engine cools, drawing the water back. Sounds pretty far-fetched to me too:)
 
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