Volvo 2003T overheats on Idle

Chris_Robb

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I have a 2003T which runs at 175F even at full power, no sign of overheating, however if she is idling, perhaps in gear, the temperature rises to 190F. I bled the water system using the nut on the Turbo, and lots of air came out. It is now much better but still rises quite quickly to 180F. Increasing the revs brings the temp down quickly.

Any ideas? We are in Greece and at times far from help, so slightly paranoid about any abnormality.
 

aluijten

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Given your remark about bleeding the water system I take it you have the indirect cooled VP2003T (not sure if a raw water cooled 2003T actually exists). If so then my guess is yo need to clean the heat-exchanger (seawater side). This can be blocked by all kinds of stuff, especially the saildrive version as Volvo Penta did not think a raw water strainer was required for the saildrive version.
Alternatively you could also have a leaking heat exchanger spilling the cooling fluid to the seawater side. But you should notice a drop in the expansion tank in that case.
Cleaning the heat-exchanger is not very hard, but requires some work and some spare parts in the form of sealing rubbers for ALL the connections you need to take loose.

I would strongly suggest to first source the spare parts and then start taking the heat-exchanger apart.

Good Luck
Arno
 

VicS

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Also make sure the raw water pump ( whether directly cooled or indirectly cooled) is OK . Impeller newish? Pump body worn?

Check the water flow out with the exhaust ... is it poor when idling?
 

ITH

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I've got an early, (cica 1990) 2003T, and my normal operating temperature - at 2300rpm - is 170F. It rises to 175F when I let it idle for a while after a long run to let the oil cool down.

Anyway, acording to the workshop manual the thermostat opening temperature is 165F, so your 175/180F readings, after bleeding the air, might indicate that VicS's suggestion would be the first one to try before taking the heat exchanger apart.
 

Chris_Robb

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Given your remark about bleeding the water system I take it you have the indirect cooled VP2003T (not sure if a raw water cooled 2003T actually exists). If so then my guess is yo need to clean the heat-exchanger (seawater side). This can be blocked by all kinds of stuff, especially the saildrive version as Volvo Penta did not think a raw water strainer was required for the saildrive version.
Alternatively you could also have a leaking heat exchanger spilling the cooling fluid to the seawater side. But you should notice a drop in the expansion tank in that case.
Cleaning the heat-exchanger is not very hard, but requires some work and some spare parts in the form of sealing rubbers for ALL the connections you need to take loose.

I would strongly suggest to first source the spare parts and then start taking the heat-exchanger apart.
Good Luck
Arno
Indirect cooling version. There is plenty of flow at idle through the exhaust, it has a new impellor, its not warn, and in relation to the header tank she doesn't loose water - I have just done 46 hours in the last 2 weeks and no loss of water. If the heat exchanger was blocked, surely it would over heat under full revs - which I can run for 10 minutes with no appreciable rise in temperature.

I take your point about getting all the spare parts first before taking the heat exchanger apart, which I may do next winter as precautionary.

Thanks for answers. Scottie to drive belt is tight and not slipping at all, so the internal water pump should be functioning ok,
 

scottie

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There is a pipe that runs through the cyl head which distributes the water to the block with a series of holes similar to a flute but two rows 1 goes to the block water jacket the other cool the injector sleeves. I would normally expect a fresh water-cooled engine not to be affected but !

Also worth checking if you get a good flow from the drains on the block.
 

Stemar

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A speculative straw to grasp at if nothing else works: Is the pump cover worn? If so, at low revs, it's possible enough water could leak back round the impellor instead of being pumped round the system to cause the rise in temperature. At higher revs, you'd get a much higher percentage circulating, so cooling would be OK.

Another long shot: The pump body is a cylinder with a piece added to the outer wall to sqeeze the impellor blades and force the water round. I presume it's still there? Centrifugal force might be enough to circulate water at high revs, but probably wouldn't at low.
 

Chris_Robb

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There is a pipe that runs through the cyl head which distributes the water to the block with a series of holes similar to a flute but two rows 1 goes to the block water jacket the other cool the injector sleeves. I would normally expect a fresh water-cooled engine not to be affected but !

Also worth checking if you get a good flow from the drains on the block.

Drained the block earlier to replace antifreeze - no problems with flow.

it really does not seem to be a problem - but if I don't inderstand something I like to understand it! I just hope it does not become a problem as having a buggered engine out here is the end...
 

Chris_Robb

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A speculative straw to grasp at if nothing else works: Is the pump cover worn? If so, at low revs, it's possible enough water could leak back round the impellor instead of being pumped round the system to cause the rise in temperature. At higher revs, you'd get a much higher percentage circulating, so cooling would be OK.

Another long shot: The pump body is a cylinder with a piece added to the outer wall to sqeeze the impellor blades and force the water round. I presume it's still there? Centrifugal force might be enough to circulate water at high revs, but probably wouldn't at low.

Hi Steve - no the pump is in excellent order - new pump etc, and the water poors out of the exhaust at tickover - so no problems in the raw water side. Its got to be something to do with the fresh water side.
 

VicS

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Checked the thermostat for correct opening? The w/shop manual gives the temp at which it just starts to open ( 164F IIRC) and a figure at which it is fully open (185F ??)
 

Chris_Robb

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Checked the thermostat for correct opening? The w/shop manual gives the temp at which it just starts to open ( 164F IIRC) and a figure at which it is fully open (185F ??)

Fitted a new Thermostat last year - actually there was nothing wrong with the old one, I had them both in a saucepan and checked the temps. They are both rated at 170F, and they were fully open.

I think I will just have to watch this, but the temp has never risen above 185. Perhaps I never noticed the temp rise in the past, but I don't think so.

Thanks
 

Chris_Robb

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Isn't there also an impellor for the fresh water side .... ? Could suffer the same faults as salt water one ..

Hi Andrew. There is a vane type pump, driven off the alternator belt. They are solid things and only go wrong I think when the bearings give out. So I really don't think this could be a cause.

I gather the weather in England is rather nicer than Greece - Last 3 days of rain, I even had the ebespatcher running it was sooo cold! Better now.

Enjoy your sailing season. Sent you a PM
 

Resolution

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Chris
It's been so hot today that all windows are wide open, we are watering the garden. Your new grass will have done a Gobi desert.
However in two weeks time.....
Peter
 

Chris_Robb

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Update on Overheat on Idle

I have not yet got to the bottom of this yet, but it appears that bleeding the nut on the Turbo stops the overheating.I then left it for 2 weeks and about 20 hours and this morning it went up to 195C ad sqealed. I bled it again and problem reduced.

So where is this air coming from. I thought it might be hydrogen from electrolosis in the engine (heaven forbid) but the test - collect bled air in up turned mug and light, did not get a bang.... So where does the air come from. We are not loosing water 60 hours from last top up.

WE motored 4 hours the day before fast into 30 knots of wind, and no sign of overheating - only on Idle, and if you raise the revs the temo quickly goes back down.

Any further ideas? Should I change the water in the coolant with fresh anti freeze mixture? Cannot think why that would work though.
 

VicS

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On some of the bigger Volvo Penta engines you can get different sizes of the new moon bit that sits inside the raw water pump to compress the impeller. A fatter new moon bit would increase the water flow at low revs and could solve your problem.


That applies to a fllexible vane pump ... the type used for the raw water not to the cetrifugal type normally used for the fresh water coolant circulation.

No suggestions to offer the Op though.

If there is any doubt about the coolant antifreeze mix I'd definiey change it but I'd not hold out much hope of it curing the problem.

Circulation pump Ok?
Any leaks? Presumably not or you be topping up the coolant regularly.

One of the diagrams I have looked at shows a nipple in place I think of the plug you are using to bleed the sytem There is a hose from there that I think goes to the expansion tank. Maybe you could modify the system to incorporate such an arrangement. Teeing into an exiting hose if necessary at the expansion tank.

It should solve the air accumulation problem but there may still be a problem with the cooling causing the overheating


SEE HERE and:-
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Happydaze

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With overheating, its not always easy to tell if the problem is in the sealed system or the flow of water to cool the sealed system, and my earlier post referred to just the raw water system.
The sealed system does use the centrifugal type pump which relies on a close fit between the vanes and the back part of the pump to push the water around the engine and calorifier etc and it is possible, if this pump has had a repair kit fitted, that the new bearing/seal has not been pushed far enough into the housing or the solid impeller has been pushed a bit too far onto the back of the shaft, making the pump ineffective at low speed.
 
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