An Overheating Engine

[Geoffrey Hammond]

Recently, I bought a second-hand boat with a Lister HRW3 engine. On its second voayge, the engine overheated - the water in the header tank boiled over. The boatyard went throgh all the standard checks. It also checked the impeller, because I was getting no hot water from the engine. The impeller was found to have broken - one of the fins had broken off. Finally, the fin was found and removed; it had lodged in the pump. A new impeller was fitted and off I went. Immediately the same problem: the engine would run for about 60 minutes at tick-over, and then it would overheat.

 

The problem will be solved; there is no evidence that it is a head-gasket matter, but no evidence of anything else either.

 

Has anyone any ideas? I promise to let the forum know what the solution is - when it is found.

 

Many thanks.

[Guest TerryL]

Recently, I bought a second-hand boat with a Lister HRW3 engine. On its second voayge, the engine overheated - the water in the header tank boiled over. The boatyard went throgh all the standard checks. It also checked the impeller, because I was getting no hot water from the engine. The impeller was found to have broken - one of the fins had broken off. Finally, the fin was found and removed; it had lodged in the pump. A new impeller was fitted and off I went. Immediately the same problem: the engine would run for about 60 minutes at tick-over, and then it would overheat.

 

The problem will be solved; there is no evidence that it is a head-gasket matter, but no evidence of anything else either.

 

Has anyone any ideas? I promise to let the forum know what the solution is - when it is found.

 

Many thanks.

 

You need to work through the system. Check the water intake and strainer is clear, no air leaks and the valve fully open. Check the pump again for condition, drive belt condition and previous blockage in the pipes and hose delamination. Check the heat exchanger for condition, blockage and internal leaks and the flow through it both the external and internal circuits, they can block up preventing full cooling capacity. Check the external water is getting away properly in the wet exhaust if you have one. Check the internal circulating pump and drive belt. Check the pressure cap is not leaking and the system is fully vented. If you find nothing there may be a blockage in the water jacket and reverse flushing or caustic soda in the system may help. One final point is if you are idling for a long time, not good for the engine anyway, there may not be sufficient coolant getting around the system, how does it work in normal use?

[Geoffrey Hammond]

You need to work through the system. Check the water intake and strainer is clear, no air leaks and the valve fully open. Check the pump again for condition, drive belt condition and previous blockage in the pipes and hose delamination. Check the heat exchanger for condition, blockage and internal leaks and the flow through it both the external and internal circuits, they can block up preventing full cooling capacity. Check the external water is getting away properly in the wet exhaust if you have one. Check the internal circulating pump and drive belt. Check the pressure cap is not leaking and the system is fully vented. If you find nothing there may be a blockage in the water jacket and reverse flushing or caustic soda in the system may help. One final point is if you are idling for a long time, not good for the engine anyway, there may not be sufficient coolant getting around the system, how does it work in normal use?

 

Many thanks for this. It is a sealed system, so that there is no water intake. If I go any faster than tick-over, it overheats more quickly.

[Timleech]

Are you saying that on the first voyage all was well, no overheating?

 

Tim

[alan_fincher]

Geoffrey,

 

How big is your skin tank, or tanks, (length, depth, and "thickness")?

 

Where is it, (or are they), located - vertically on the swim(s), or flat on the bottom of the boat?

 

Do you know for certain they have internal baffles in them?

 

If you have done a trip where it didn't overheat, but it did on a subsequent one, then hopefully inadequate cooling area isn't the cause.

 

But some boats are built with inadequate skin tanks, (as we learnt the hard way), so it's worth ruling it out.

 

Who built the shell, please ?

 

One final thought - I don't know the HRW3. Is using an impeller based pump, (I assume you mean something like a Jabsco, with rubber blades), the normal means of circulating the coolant on these engines, please ?

 

Alan

[Timleech]

Geoffrey,

 

 

One final thought - I don't know the HRW3. Is using an impeller based pump, (I assume you mean something like a Jabsco, with rubber blades), the normal means of circulating the coolant on these engines, please ?

 

Alan

 

The standard marine version is set up for raw water cooling via a heat exchanger, so there are two pumps - a Jabsco for the raw water, and a vane type for the internal coolant.

Incidentally I'm on the lookout for one of the vane pumps at a decent price.

 

Tim

[Guest TerryL]

Many thanks for this. It is a sealed system, so that there is no water intake. If I go any faster than tick-over, it overheats more quickly.

 

Have you checked the thermostat for sticking in the closed position, change it if in any doubt or leave it out temporarily to check, otherwise there's no reason to stop the coolant circulating in a keel cooled system provided the pipes are clear and sound and the circulator is working.

[alan_fincher]

The standard marine version is set up for raw water cooling via a heat exchanger, so there are two pumps - a Jabsco for the raw water, and a vane type for the internal coolant.

Thanks, Tim.....

 

I wondered if it was something like that.

 

So is it normal with a big water cooled Lister using keel cooling to always have two separate close water circuits, the engine one and the skin tank one, with a heat exchanger in between the two ?

 

Not an issue I guess, but clearly more complex than it needs be, and with an additional pump that can misbehave.

 

I'm kind of interested of this is an HRW3, whether it's actually in a traditional engine room, rather than at the back, which can mean a skin tank on the base of the boat, rather than the sides.

 

I'm certainly keen for OP to tell us whether the trip where it didn't overheat had similar characteristics to later ones where it did, as that would tend to rule out issues with skin tank size or design, (in my view).

[Timleech]

Many thanks for this. It is a sealed system, so that there is no water intake. If I go any faster than tick-over, it overheats more quickly.

 

Just a thought, as you're new to the boat, hope you take it in the right spirit....

 

Are you absolutely sure that there isn't a raw water intake, & you've forgotten to turn it on or it's become blocked?

 

Tim

Edited August 24, 2008 by Timleech

[Geoffrey Hammond]

Many thanks for all the comments this far.

 

On the first voyage of three weeks, there was one case of overheating three days in; I put that down to bad luck and a very hot day. For the next two and a half weeks nothing happened.

 

On the second voyage, it happened after three hours and then subsequently six times whilst trying to get to the boat back and on a further test voyage.

 

The engine is in a traditional engine room. The boat was built by Stow Hill.

 

As far as I am aware, the skin tank is on one swim.

 

As far as I am aware there is no raw water intake.

 

The thermostat seems to be working correctly.

 

Very kindly, Paul Redshaw at Braunston is having a look at it for me.

[alan_fincher]

Thanks Geoffrey,

 

If you could cruise for two and a half weeks with no overheat, then poor skin tank design sounds unlikely to be a prime cause, (fortunately!).

 

Anyway, I'd expect Stowe Hill to be able to get it right.

 

I'm sure Paul Redshaw will be able to come up with better advice by being hands on, than we can by speculation.

 

Some kind of blockage or air lock is my guess, but it really is no more than a guess.

 

It's worth knowing exactly where your skin tank is, (simply follow the hoses from the engine!), as you can tell a lot just by laying hands on it. When everything is up to temperature, it will probably be too hot to touch at the top, where the inlet hose goes in from the engine, but should feel much cooler at the bottom, where the return hose leaves the tank, back to the engine. (More accurate assessment can be made by buying a cheap infra-red thermometer from somewhere like Maplins - usually well under £20 for a basic one).

 

Good luck with resolving.....

 

Alan

[buggsy]

Recently, I bought a second-hand boat with a Lister HRW3 engine. On its second voayge, the engine overheated - the water in the header tank boiled over. The boatyard went throgh all the standard checks. It also checked the impeller, because I was getting no hot water from the engine. The impeller was found to have broken - one of the fins had broken off. Finally, the fin was found and removed; it had lodged in the pump. A new impeller was fitted and off I went. Immediately the same problem: the engine would run for about 60 minutes at tick-over, and then it would overheat.

 

The problem will be solved; there is no evidence that it is a head-gasket matter, but no evidence of anything else either.

 

Has anyone any ideas? I promise to let the forum know what the solution is - when it is found.

 

Many thanks.

 

Hi Geoffrey,

 

i had a similar problem with a Perkins D3.152, we tried all sorts of remedies and had carried out two different checks to prove the head gasket was ok. Eventually with the help of an ex HGV fitter we replaced the head gasket and found this totally cured the problem. The engine now its at about 78 degrees and we have plenty of hot water in the calorifier.what we did find that not all the head bolts were tightened sufficiently which could have caused the intermittent faults.

 

hope this helps,

 

steve

[RobinJ]

The engine is in a traditional engine room. The boat was built by Stow Hill.

 

As far as I am aware, the skin tank is on one swim.

 

As far as I am aware there is no raw water intake.

 

The thermostat seems to be working correctly.

If the impeller has failed, is it waer and tear or has something gone through it (lump of rust etc.)?

Worth checking the heat exchanger, back flushing to make sure its not blocked, in fact it may be worth doing that to the primary circuit too.

The Lister is not one I'm familiar with, but many engines use this system because the water pump on the engine only has limited pull.

If it is heating a calorifier circuit and that is not getting hot, there is something wrong with the primary, the secondary failure might just be coincidental?

If a head gasket goes, you can usually tell by leaving the filler cap off, all the smoke and bubbles come out!