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Volvopenta D1-30 losing coolant, reservoir cap puzzel.

VicS

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Joined
13 Jul 2002
Messages
46,357
Does the coolant appear in the bilge, or is it "disappearing"?

The pressure cap needs to be on - cooling systems run at around 4-7psi, this is done to raise the boiling point of the water so that no steam can be created in the engine during use (air is a poor conductor of heat).

I've only briefly skimmed through the posts, so may have missed something but if you are losing water and it's not in the bilges then, as mentioned above, it has to be going out through the engine. I'm also suggesting heat exchanger, the rubber end caps can be a source of leaks into the raw water system, which then exits out through the exhaust.
I don't think this one has rubber end caps
 

VicS

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Joined
13 Jul 2002
Messages
46,357
Thanks VicS again for your support, I will try doing this again although I have ran the engine several times and the level remains constant when the cap is not screwed on tight, but when tight the level drops. Cheers
I reckon air is being trapped somewhere
Check the small hose between the top of the heat exchanger and the coolant reservoir and also the connections at each end for blockages (especially the heat exchanger end).
 
Last edited:

tid2021

New member
Joined
18 Jul 2021
Messages
12
I reckon air is being trapped somewhere
Check the small hose between the top of the heat exchanger and the coolant reservoir and also the connections at each end for blockages (especially the heat exchanger end).
Hi
Thanks I have taken the water pump off to get serviced so I can not run the engine.

See attached photos,

Webp.net-resizeimage (1).jpgWebp.net-resizeimage (2).jpgtid1.jpg


the timings were 1st photo top up at 1341 and second photo at 1642 the in third photo shows where the pump inlet to the heat exchanger is. Yesterday I went to the boat and there was very little drop in the reservoir

I am wondering like you said if there was air trapped in the system which was slowly comming out.

Or as people have suggested it may be a blown head gasket and the coolant is finding its way in the the head. But my thinking is this would only happen when the engine is running not when stopped.

I can turn the engine over by the fly wheel and belt. I would like to ask if this would be possible if the coolant was in the head /cylinders. If not this would illiminate the gasket.
 
Joined
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Hi
Thanks I have taken the water pump off to get serviced so I can not run the engine.

See attached photos,

View attachment 119326View attachment 119327View attachment 119328


the timings were 1st photo top up at 1341 and second photo at 1642 the in third photo shows where the pump inlet to the heat exchanger is. Yesterday I went to the boat and there was very little drop in the reservoir

I am wondering like you said if there was air trapped in the system which was slowly comming out.

Or as people have suggested it may be a blown head gasket and the coolant is finding its way in the the head. But my thinking is this would only happen when the engine is running not when stopped.

I can turn the engine over by the fly wheel and belt. I would like to ask if this would be possible if the coolant was in the head /cylinders. If not this would illiminate the gasket.
When the engine is running then combustion products normally find their way into the cooling system. When the engine is stopped the reverse happens and coolant finds its way into the cylinders and, from there, into the oil sump. If it doesn't drain through into the sump then it might well hydrolock the engine. Have you checked the oil for water or for an increasing level?

The fact that you can turn the engine over using the pulley means that it is not hydrolocked but it does sound as if compression is rather low which might indicate a failed head gasket. If there is still no physical evidence of any of the missing coolant and the level does not eventually stabilise when you add more then it must be going out through the exhaust. I would arrange for a compression test as that is quick and simple and should provide a definitive answer.

Richard
 
Last edited:

oldharry

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30 May 2001
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9,349
Location
North from the Nab about 10 miles
When the engine is running then combustion products normally find their way into the cooling system. When the engine is stopped the reverse happens and coolant finds its way into the cylinders and, from there, into the oil sump. If it doesn't drain through into the sump then it might well hydrolock the engine. Have you checked the oil for water or for an increasing level?

The fact that you can turn the engine over using the pulley means that it is not hydrolocked but it does sound as if compression is rather low which might indicate a failed head gasket. If there is still no physical evidence of any of the missing coolant and the level does not eventually stabilise when you add more then it must be going out through the exhaust. I would arrange for a compression test as that is quick and simple and should provide a definitive answer.

Richard
Much better to get a leak down test if going down that route. This will highlight both failed head gasket and piston wear levels to an experienced mechanic. Compression tests on diesels dont show a great deal because of the high pressures involved.
 

VicS

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Joined
13 Jul 2002
Messages
46,357
Hi
Thanks I have taken the water pump off to get serviced so I can not run the engine.

See attached photos,

View attachment 119326View attachment 119327View attachment 119328
I'd not realised the level in the reservoir was falling while just standing.
It suggests a leak either into the HE or a head gasket leak.
I think there would be other symptoms of a head gasket failure severe enough for it to leak as fast as your pictures indicate and also that the level would fall further. Don't loose sight of the possibility though.

Maybe there is a HE tube leak or one of the tube nest end O rings is leaking.
 
Joined
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Much better to get a leak down test if going down that route. This will highlight both failed head gasket and piston wear levels to an experienced mechanic. Compression tests on diesels dont show a great deal because of the high pressures involved.
I agree .... but a leak down test is more specialised and not usually an option for the practical boat owner and therefore probably more expensive. Compression testing on diesel engines is a standard procedure and will quickly show if there is a lack of compression although I accept that it is not as good at identifying the source of the problem. However, the head has to come off either way.

Richard
 

179580

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Joined
19 Jun 2020
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230
The very thing that all you experts here have missed is a pressure test on the cooling system. Very first go to.
 

179580

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230
Never done that. Never needed to. ;)

Richard
Well that just elaborates the difference between an engineer or a makey learney. Pressure test while engine stopped gives an indication of integrity. Start engine and observe high pressure rise indicates leak from combustion gasses. Many kits containing adaptors and pumps from suppliers such as Sealey, Sykes-Picovant to perform this common basic diagnostic test
 
Joined
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Messages
29,305
Location
Home UK Midlands / Boat Croatia
Well that just elaborates the difference between an engineer or a makey learney. Pressure test while engine stopped gives an indication of integrity. Start engine and observe high pressure rise indicates leak from combustion gasses. Many kits containing adaptors and pumps from suppliers such as Sealey, Sykes-Picovant to perform this common basic diagnostic test
Or perhaps it elaborates the difference between and engineer and someone who really understands engines. (y)

Richard
 

tid2021

New member
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18 Jul 2021
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12
Hi to all those following and providing suggestions and comments.

I was at the boat yesterday and the level in the reservior has stabelized :). I have had the serviced water pump returned and fitted :).

I then went to run the engine. On the engine turning over you could see coolant spouting out of the exhaust :mad::sick: so much so that you could see the water turn yellow beneathe the exhaust. I am not an engineer (actually a retired merchant navy captian) but with I think this strongly indicates there is coolant in the cylinders. So now at last I have found a Volvopenta service company who can come out and have a look sometime next week.

Again thanks to all who have read and contributed.
The joys of having a boat.
Hopefully happy sailing soon
 
Joined
5 Nov 2009
Messages
29,305
Location
Home UK Midlands / Boat Croatia
Hi to all those following and providing suggestions and comments.

I was at the boat yesterday and the level in the reservior has stabelized :). I have had the serviced water pump returned and fitted :).

I then went to run the engine. On the engine turning over you could see coolant spouting out of the exhaust :mad::sick: so much so that you could see the water turn yellow beneathe the exhaust. I am not an engineer (actually a retired merchant navy captian) but with I think this strongly indicates there is coolant in the cylinders. So now at last I have found a Volvopenta service company who can come out and have a look sometime next week.

Again thanks to all who have read and contributed.
The joys of having a boat.
Hopefully happy sailing soon
It is not necessarily coolant in the cylinders as many posts in this thread make clear. In fact, as I said, if your engine is turning over properly then I doubt whether that is the problem.

If the engineer solely focuses on the coolant in cylinder explanation without exploring the more obvious heat exchanger option, then politely explain to him that you have already consulted the best engineers in the UK. (y)

Richard
 

dankilb

Active member
Joined
23 Jan 2008
Messages
686
It is not necessarily coolant in the cylinders as many posts in this thread make clear. In fact, as I said, if your engine is turning over properly then I doubt whether that is the problem.

If the engineer solely focuses on the coolant in cylinder explanation without exploring the more obvious heat exchanger option, then politely explain to him that you have already consulted the best engineers in the UK. (y)

Richard
Exactly what I thought (despite only being a makey learney myself 😂).

Cannot see how the coolant could survive combustion in the cylinders in a state that could reveal itself by colour in the exhaust (try clouds of glycol-smelling steam/white smoke instead!). Nor can I see how the cylinders could accommodate enough coolant without hydrolocking.

If it's heaving out in such quantities, it's finding another route, IMHO.

And on the 'pressure test' - only useful for garages to evidence faults to customers (the mechanic themselves likely having already deduced - no coolant leaking from hoses, radiator, heater core, etc. = then it's into the block somewhere). Completely useless when you've got a heat exchanger in the system (unless you're testing the h/e only).
 

VicS

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Joined
13 Jul 2002
Messages
46,357
Hi to all those following and providing suggestions and comments.

I was at the boat yesterday and the level in the reservior has stabelized :). I have had the serviced water pump returned and fitted :).

I then went to run the engine. On the engine turning over you could see coolant spouting out of the exhaust :mad::sick: so much so that you could see the water turn yellow beneathe the exhaust. I am not an engineer (actually a retired merchant navy captian) but with I think this strongly indicates there is coolant in the cylinders. So now at last I have found a Volvopenta service company who can come out and have a look sometime next week.

Again thanks to all who have read and contributed.
The joys of having a boat.
Hopefully happy sailing soon
Maybe, but the volume of coolant you observed would have hydro-locked the engine unless it leaked to a cylinder on its power stroke or exhaust stroke.

signs of water (coolant) in the engine oil would go a long way towards confirming your theory.

Coolant leaking into the raw water side of the HE will have been blown out of the exhaust so your observations do not discount that as a possibility
 

VicS

Well-known member
Joined
13 Jul 2002
Messages
46,357
I'm suspicious about the heat exchanger, No end caps sounds odd, can we have a photo please?
Does not have the rubber end caps as suggested in #20

Look at the parts diagrams and you will see how this one is built

MPE (heat exchanger)
and
MPE (heat exchanger components)
 
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