lister overheating

[Psychalist]

Our conclusion was based on the theory that a correct seal would mean no staining - i.e. a similar grey all round and not the darker carbon staining seen on the near side of cylinder 1 (the foreground in the photograph). The water gallery is definitely covered by that staining and the gasket sealant looks darker where the hole goes through it. I might add the gasket might also have been an after market part rather than the official Lister Petter part - which was used in the rebuild, that had blue coloured sealant.

 

If @SiFi wants a new spring, it might be worth talking to Darwen Diesels.

[Peugeot 106]

10 minutes ago, Psychalist said:

Our conclusion was based on the theory that a correct seal would mean no staining - i.e. a similar grey all round and not the darker carbon staining seen on the near side of cylinder 1 (the foreground in the photograph). The water gallery is definitely covered by that staining and the gasket sealant looks darker where the hole goes through it. I might add the gasket might also have been an after market part rather than the official Lister Petter part - which was used in the rebuild, that had blue coloured sealant.

 

If @SiFi wants a new spring, it might be worth talking to Darwen Diesels.

Glad I asked. I thought you mean’t the inside edge of the gasket not the surface of the sealing metal ring part. It is now clearer. It was probably more obvious to you as you could see the whole surface. I still think RTV has been used with that gasket which is not recommended. I remember a Lancaster area engineer slathering sealant all over a gasket that clearly should have been fitted dry with the comment “ I always do belt and braces”

Thanks for that. Glad non of us need new engines!

 

[Psychalist]

I don't think any sealant was used. These gaskets come pre-coated as per this new one...

[Peugeot 106]

On 29/06/2023 at 02:06, Steve56 said:

The thermostat could be called double acting. It has an extra plate on the bottom. The reason for this is that the Alpha engines had an internal bypass to allow coolant to flow around the block until the thermostat opens. This is to ensure you don't get localised hot spots within the block. As the thermostat opens this extra plate closes the bypass and allows coolant to be returned to the skin tank. The reason for not running without a  thermostat is that the coolant can short circuit and cause an overheat situation. The coolant will take the path of least resistance.

You are correct. It is definitely the other way around.

Steve it would be very useful to me and maybe others if you could sketch a flow diagram of the relationship between skin tank circuit, engine circuit, circulating pump and thermostat on the Alpha 400 series.Sorry but I can’t get my head round it. Many thanks in anticipation 

[Tony Brooks]

41 minutes ago, Peugeot 106 said:

Steve it would be very useful to me and maybe others if you could sketch a flow diagram of the relationship between skin tank circuit, engine circuit, circulating pump and thermostat on the Alpha 400 series.Sorry but I can’t get my head round it. Many thanks in anticipation 

This is the general principle and I would expect the Alpha to comply.

 

Out of the circulating pump and into the body of the block and up into the head. From the head into the thermostat chamber which has two outlets in it. A large one in the top (usually in the cover) that goes to the skin tank. This one works just as any other system with a thermostat and is closed when COLD. The one at the bottom, below the thermostat is usually smaller and is OPEN when the engine is cold. This usually leads into the water pump.

 

There is a large washer like object hanging below the thermostat and operated by the thermostat so as the thermostat starts to open at the top to allow coolant into the skin tank, the washer at the bottom closes the path back into the water pump.

[David Mack]

And somewhat crudely shown here.

[Tracy D'arth]

13 hours ago, Tony Brooks said:

This is the general principle and I would expect the Alpha to comply.

 

Out of the circulating pump and into the body of the block and up into the head. From the head into the thermostat chamber which has two outlets in it. A large one in the top (usually in the cover) that goes to the skin tank. This one works just as any other system with a thermostat and is closed when COLD. The one at the bottom, below the thermostat is usually smaller and is OPEN when the engine is cold. This usually leads into the water pump.

 

There is a large washer like object hanging below the thermostat and operated by the thermostat so as the thermostat starts to open at the top to allow coolant into the skin tank, the washer at the bottom closes the path back into the water pump.

This is what rang the bell with me, if that stat does not close the bypass back to the pump  there is insufficient circulation through the skin tank and the engine overheats. I think a similar situation can occur if the calorimeter circuit is either tapped into the wrong place or is allowed too have much flow. It fails to dissipate sufficient heat and the flow in the skin tank is diminished causing overheating again.

[Tony Brooks]

2 hours ago, Tracy D'arth said:

This is what rang the bell with me, if that stat does not close the bypass back to the pump  there is insufficient circulation through the skin tank and the engine overheats. I think a similar situation can occur if the calorimeter circuit is either tapped into the wrong place or is allowed too have much flow. It fails to dissipate sufficient heat and the flow in the skin tank is diminished causing overheating again.

 

Totally agree, which is why I was trying to ensure I understood exactly how the calorifier was connected to this particular engine - and I still don't.

5 hours ago, David Mack said:

And somewhat crudely shown here.

 

That is a good explanation, thanks.

[Peugeot 106]

21 hours ago, Tony Brooks said:

This is the general principle and I would expect the Alpha to comply.

 

Out of the circulating pump and into the body of the block and up into the head. From the head into the thermostat chamber which has two outlets in it. A large one in the top (usually in the cover) that goes to the skin tank. This one works just as any other system with a thermostat and is closed when COLD. The one at the bottom, below the thermostat is usually smaller and is OPEN when the engine is cold. This usually leads into the water pump.

 

There is a large washer like object hanging below the thermostat and operated by the thermostat so as the thermostat starts to open at the top to allow coolant into the skin tank, the washer at the bottom closes the path back into the water pump.

Thank you very much. I still can’t get my head round why my recovery bottle takes so long to “recover” and why if I use the engine again before it has recovered  the same amount of water is expelled again into the bottle. It’s almost as if the fluid had to be dragged through the jiggle pin on the thermostat it takes so long. The bottom bypass plate has a sizeable cutout so I don’t think it’s anything to do with that. 
it’s all a bit academic as I just tip the recovery bottle into the mannicooler filler in the morning if the bottle is still too full and I’ve never had overheating.

I just don’t see why it doesn’t work as expected. When I take the cap off it all goes glug glug so I think it’s pretty airtight. It also “recovers” if I leave it for another day

Maybe this works fine on a car where the water volumes are small and revovery takes place when the thermostat is open before a slug of cold water from the skin tank closes the theemostat and it all had to be sucked through the jiggle pin 

[Tony Brooks]

1 hour ago, Peugeot 106 said:

Thank you very much. I still can’t get my head round why my recovery bottle takes so long to “recover” and why if I use the engine again before it has recovered  the same amount of water is expelled again into the bottle. It’s almost as if the fluid had to be dragged through the jiggle pin on the thermostat it takes so long. The bottom bypass plate has a sizeable cutout so I don’t think it’s anything to do with that. 
it’s all a bit academic as I just tip the recovery bottle into the mannicooler filler in the morning if the bottle is still too full and I’ve never had overheating.

I just don’t see why it doesn’t work as expected. When I take the cap off it all goes glug glug so I think it’s pretty airtight. It also “recovers” if I leave it for another day

Maybe this works fine on a car where the water volumes are small and revovery takes place when the thermostat is open before a slug of cold water from the skin tank closes the theemostat and it all had to be sucked through the jiggle pin 

 

We need to know more about the cap on the mannicooler, how the expansion tank is plumbed into the system, the relative levels between the tank and mannicooler, and more about the cap on the expansion bottle.

 

If the cap on the mannicooler is not vacuum (depression) tight then as the coolant cools it may well suck air into the engine rather than coolant from the expansion tank. I think that you suspect a head gasket fault, and if so the contracting coolant might be sucking air via the head gasket.

 

What do you think is doing any dragging through the jiggle pin in the thermostat? The water pump pushes the coolant as much as it sucks it. If there were any significant flow upwards the jiggle pin would rise in the current and all but seal the hole.

 

The fact you say removing the cap from the pressure cap causes it to go glug, glug, glug, suggest to me that there is no working vacuum valve in the pressure cap, so you have to take the cap off to let air in and destroy the depression the cooling coolant created.

Edited July 11, 2023 by Tony Brooks

[Peugeot 106]

12 hours ago, Tony Brooks said:

 

We need to know more about the cap on the mannicooler, how the expansion tank is plumbed into the system, the relative levels between the tank and mannicooler, and more about the cap on the expansion bottle.

 

If the cap on the mannicooler is not vacuum (depression) tight then as the coolant cools it may well suck air into the engine rather than coolant from the expansion tank. I think that you suspect a head gasket fault, and if so the contracting coolant might be sucking air via the head gasket.

 

What do you think is doing any dragging through the jiggle pin in the thermostat? The water pump pushes the coolant as much as it sucks it. If there were any significant flow upwards the jiggle pin would rise in the current and all but seal the hole.

 

The fact you say removing the cap from the pressure cap causes it to go glug, glug, glug, suggest to me that there is no working vacuum valve in the pressure cap, so you have to take the cap off to let air in and destroy the depression the cooling coolant created.

I think you might have solved it. The only pressure cap is on the mannicooler. It is I believe the correct type with a rubber seal. I pressure tested the mannicooler with the cap after getting plate and hose connectors welded on so I didn’t need the polar end caps. 
But when the mannicooler is sucking coolant back in maybe some air is being sucked passed the cap which I haven’t tested on vacuum. Maybe this intermittently seals? The return flap on the cap seems fine but is the rubber seal (it is pretty new) working when under pressure but not so good under vacuum

 

the reason I think jiggle pin (I think mine might just be a hole) is that the flow rate seems so low. That’s the only reason I think it might be involved based on no evidence whatever

 

i changed the head gasket a couple of years ago. There is no evidence of contamination of coolant or oil or smoke and I realise it could just be leaking into the coolant but since I changed it nothing has changed. despite a few hard runs RIbble Link x 3, Trent upstream. Severn Estuary, Avon and now the Thames from Limehouse to Lechlade. I admit to not changing the head bolts but was told by a LP engineer not to bother but get the torques correct which I did to the book 

My expansion bottle is simply a milk bottle on the bilge without top and a 8mm rubber fuel hose connected to the pipe off the filler neck and dipped into the coolant. It is always submerged and doesn’t touch the bottom of the bottle. I should add that I never need to add coolant to the system. I only have to redistribute it.

Any ideas how to vacuum test the mannicooler and cap? Should that be my next test?
 

Thanks a lot Tony

[Tony Brooks]

2 hours ago, Peugeot 106 said:

I think you might have solved it. The only pressure cap is on the mannicooler. It is I believe the correct type with a rubber seal. I pressure tested the mannicooler with the cap after getting plate and hose connectors welded on so I didn’t need the polar end caps. 
But when the mannicooler is sucking coolant back in maybe some air is being sucked passed the cap which I haven’t tested on vacuum. Maybe this intermittently seals? The return flap on the cap seems fine but is the rubber seal (it is pretty new) working when under pressure but not so good under vacuum

 

the reason I think jiggle pin (I think mine might just be a hole) is that the flow rate seems so low. That’s the only reason I think it might be involved based on no evidence whatever

 

i changed the head gasket a couple of years ago. There is no evidence of contamination of coolant or oil or smoke and I realise it could just be leaking into the coolant but since I changed it nothing has changed. despite a few hard runs RIbble Link x 3, Trent upstream. Severn Estuary, Avon and now the Thames from Limehouse to Lechlade. I admit to not changing the head bolts but was told by a LP engineer not to bother but get the torques correct which I did to the book 

My expansion bottle is simply a milk bottle on the bilge without top and a 8mm rubber fuel hose connected to the pipe off the filler neck and dipped into the coolant. It is always submerged and doesn’t touch the bottom of the bottle. I should add that I never need to add coolant to the system. I only have to redistribute it.

Any ideas how to vacuum test the mannicooler and cap? Should that be my next test?
 

Thanks a lot Tony

 

Let's not jump to conclusions, and note I asked for more details.

 

The pressure caps on mannicoolers come in three types. Long and short neck with the spring-loaded pressure seal hanging down from the cap and sealing in the base of the neck. These also have a vacuum valve incorporated into the pressure seal. depending upon application, these MIGHT also have a rubber seal under the cap*. My guess is that yours does not. The other type is just the twist on cap with a rubber seal under the cap and with no pressure/vacuum valve. These tend to be used where the pressure cap is on the expansion vessel and there is no vent pipe on the filler neck.

 

* this type tends to be used where the vent on the filler neck is connected into an expansion tank.

 

To complicate matters, the first type often has a brass diaphragm that bears on the top of the filler neck and they rarely make an air/vacuum tight seal. Even the type with a rubber seal under the cap a distorted filler neck can prevent the sealing.

 

I think that you need the type of cap with the spring-loaded pressure/vacuum seal PLUS the rubber seal right under the cap.

 

We had a pressure cap tester in all the garages I worked in but none could test the vacuum valve. As long as you can get your lips to seal around the pressure seal, you could try sucking it and it should be fairly east to suck. You can also manually flick the vacuum valve to ensure it has not stuck onto a rubber seal.

 

 

 

 

 

 

Edited July 12, 2023 by Tony Brooks

[Peugeot 106]

37 minutes ago, Tony Brooks said:

 

Let's not jump to conclusions, and note I asked for more details.

 

The pressure caps on mannicoolers come in three types. Long and short neck with the spring-loaded pressure seal hanging down from the cap and sealing in the base of the neck. These also have a vacuum valve incorporated into the pressure seal. depending upon application, these MIGHT also have a rubber seal under the cap*. My guess is that yours does not. The other type is just the twist on cap with a rubber seal under the cap and with no pressure/vacuum valve. These tend to be used where the pressure cap is on the expansion vessel and there is no vent pipe on the filler neck.

 

* this type tends to be used where the vent on the filler neck is connected into an expansion tank.

 

To complicate matters, the first type often has a brass diaphragm that bears on the top of the filler neck and they rarely make an air/vacuum tight seal. Even the type with a rubber seal under the cap a distorted filler neck can prevent the sealing.

 

So, do you have a vent in the filler neck? If so getting a pressure cap with a seal under the cap is unlikely to make much difference.

 

We had a pressure cap tester in all the garages I worked in but none could test the vacuum valve. As long as you can get your lips to seal around the pressure seal, you could try sucking it and it should be fairly east to suck. You can also manually flick the vacuum valve to ensure it has not stuck onto a rubber seal.

 

 

 

 

 

 

Thanks Tony I will send you a photo later when I’m back. 

[Peugeot 106]

3 hours ago, Tony Brooks said:

 

Let's not jump to conclusions, and note I asked for more details.

 

The pressure caps on mannicoolers come in three types. Long and short neck with the spring-loaded pressure seal hanging down from the cap and sealing in the base of the neck. These also have a vacuum valve incorporated into the pressure seal. depending upon application, these MIGHT also have a rubber seal under the cap*. My guess is that yours does not. The other type is just the twist on cap with a rubber seal under the cap and with no pressure/vacuum valve. These tend to be used where the pressure cap is on the expansion vessel and there is no vent pipe on the filler neck.

 

* this type tends to be used where the vent on the filler neck is connected into an expansion tank.

 

To complicate matters, the first type often has a brass diaphragm that bears on the top of the filler neck and they rarely make an air/vacuum tight seal. Even the type with a rubber seal under the cap a distorted filler neck can prevent the sealing.

 

I think that you need the type of cap with the spring-loaded pressure/vacuum seal PLUS the rubber seal right under the cap.

 

We had a pressure cap tester in all the garages I worked in but none could test the vacuum valve. As long as you can get your lips to seal around the pressure seal, you could try sucking it and it should be fairly east to suck. You can also manually flick the vacuum valve to ensure it has not stuck onto a rubber seal.

 

 

 

 

 

 

Here are pictures of the recovery (milk bottle), filler neck and overflow piped into the bottle and the pressure cap

The pressure cap has two rubber seals too and bottom which judging by the indentation in them are sealing well. The sealing surfaces on the neck look smooth and undamaged. The brass plate at the bottom opens up fairly easily if you pull it. It’s not stuck to anything . The cap is only around 200 hours old so in good condition. It is stamped LBS15 G.1050.

I tried sucking with my lips around the rubber seal but it was difficult to keep a seal.

Could you confirm that this looks like the correct pressure cap?

[Tony Brooks]

1 hour ago, Peugeot 106 said:

Here are pictures of the recovery (milk bottle), filler neck and overflow piped into the bottle and the pressure cap

The pressure cap has two rubber seals too and bottom which judging by the indentation in them are sealing well. The sealing surfaces on the neck look smooth and undamaged. The brass plate at the bottom opens up fairly easily if you pull it. It’s not stuck to anything . The cap is only around 200 hours old so in good condition. It is stamped LBS15 G.1050.

I tried sucking with my lips around the rubber seal but it was difficult to keep a seal.

Could you confirm that this looks like the correct pressure cap?

 

 

 

if the engine needs a 15PSI cap, then yes, it all looks correct.

 

The only other place where air could be sucked in is where the filler fits into the manifold, but as there are no signs of staining from leaks I doubt it is, especially as you have confirmed the vacuum valve opens easily. So that seems to have been a blind ally, sorry.

 

Can you get the expansion bottle up much higher so the vacuum does not have to "suck" so hard to draw coolant back into the engine.

[Peugeot 106]

1 minute ago, Tony Brooks said:

 

if the engine needs a 15PSI cap, then yes, it all looks correct.

 

The only other place where air could be sucked in is where the filler fits into the manifold, but as there are no signs of staining from leaks I doubt it is, especially as you have confirmed the vacuum valve opens easily. So that seems to have been a blind ally, sorry.

 

Can you get the expansion bottle up much higher so the vacuum does not have to "suck" so hard to draw coolant back into the engine.

Yes 15psi is fine I checked with Lister Petter when I got rid of the useless Polar Caps. It used to be rated much lower to safeguard the caps.  It’s s pity I can’t manually open the suction valve when it’s recovering! 
i’ve got a esecondhand exhaust manifold and proper tank with two connections which I will probably fit this winter. Does the connection to the bottom of the expansion tank have to go to the bottom of the skin tank or can it go half way up the hose from the bottom of the skin tank to the circulating pump. After that its off with its head again if necessary 
thanks Tony

[Tony Brooks]

I may be wrong here, but I would want to circulate coolant through the tank, so I would fit the lowest tank connection into the return to the water pump, this could be the skin tank lower connection. The upper connection I would take from the outlet side of the water pump, so possibly the feed from the engine into the skin tank. That way, any air or gasses circulating should vent into the tank as the bubbles come through.

 

However, I would prefer someone who really knows these Listers to advise waht Lister say.

[RLWP]

13 hours ago, Tony Brooks said:

However, I would prefer someone who really knows these Listers to advise waht Lister say.

 

Apologies, I haven't been paying attention - what's the question?

 

Richard

[Tony Brooks]

5 minutes ago, RLWP said:

 

Apologies, I haven't been paying attention - what's the question?

 

Richard

 

He was asking about how to connect a two port expansion bottle on that engine. I gave him a generic answer but acknowledged it is not Lister specific. He might be planning to buy a generic expansion vessel.

[RLWP]

17 minutes ago, Tony Brooks said:

 

He was asking about how to connect a two port expansion bottle on that engine. I gave him a generic answer but acknowledged it is not Lister specific. He might be planning to buy a generic expansion vessel.

 

Oh blimey - I've been keeping up with the other engine problem and skipping this one. I'll have to read back to see what's going on

Thanks Tony

 

Richard

On 11/07/2023 at 11:58, Tracy D'arth said:

This is what rang the bell with me, if that stat does not close the bypass back to the pump  there is insufficient circulation through the skin tank and the engine overheats.

 

Have you come across the folklore engineering solution of removing the thremostat applied to an Alpha?

 

First off, no water will come out of the outlet pipes (there you go mate, your pumps knackered)

 

Secondly, the engine boils really quickly.

 

Richard

On 11/07/2023 at 21:48, Tony Brooks said:

The fact you say removing the cap from the pressure cap causes it to go glug, glug, glug, suggest to me that there is no working vacuum valve in the pressure cap, so you have to take the cap off to let air in and destroy the depression the cooling coolant created.

 

THIS^^^

 

 

I can't see the anti-vacuum part of that cap. Without one it won't draw coolant back

On our BMC, I always leave an air space in the manifold tank

 

Richard

Edited July 13, 2023 by RLWP

[Peugeot 106]

26 minutes ago, RLWP said:

 

Oh blimey - I've been keeping up with the other engine problem and skipping this one. I'll have to read back to see what's going on

Thanks Tony

 

Richard

 

Have you come across the folklore engineering solution of removing the thremostat applied to an Alpha?

 

First off, no water will come out of the outlet pipes (there you go mate, your pumps knackered)

 

Secondly, the engine boils really quickly.

 

Richard

 

THIS^^^

 

 

I can't see the anti-vacuum part of that cap. Without one it won't draw coolant back

On our BMC, I always leave an air space in the manifold tank

 

Richard

The anti vacuum bit is the bronze coloured disc in the centre which is spring loaded and lifts when a vacuum is applied and allows air back in.  Maybe the spring is too strong? Don’t worry Richard I expect it’s your silly season though on the Thames it’s to quote lock keepers “eerily quiet”. I have a theory that no body can find competent mechanics to fix or service their engines! Good Luck

[Steve56]

Back in the day this is the type of header tank supplied by Lister as an optional extra for use with the Polar manifold. It would be piped up to the manifold overflow pipe. The manifold would then be fitted with a plain non pressurised cap, and the pressure cap would be fitted to this header tank. Also the original water pump fitted to that engine would have been a non bypass type, therefore it would have a standard type thermostat without the extra flap fitted. Also noticed previously mention of thermostat jiggle pin. On the set up above the jiggle pin was removed on assembly. This was to alow a small amount of water circulation before the thermostat opened. As the pump was non bypass this ensured there were no internal localised hot spots. By the time Lister moved over to the later type cooling system the engine was also being fitted with the later pump. If the pump has ever been changed the chances are it will be the later type pump as the early pumps were made obsolete but were totally interchangeable. 

[Tony Brooks]

1 hour ago, RLWP said:

On 11/07/2023 at 21:48, Tony Brooks said:

The fact you say removing the cap from the pressure cap causes it to go glug, glug, glug, suggest to me that there is no working vacuum valve in the pressure cap, so you have to take the cap off to let air in and destroy the depression the cooling coolant created.

 

THIS^^^

 

Having seen the photo of his set-up, I no longer think so. It is a "milk bottle" on the baseplate with a hose from the normal filler neck overflow. I am now wondering if he has some hose(s) that are very soft so as the depression develops they collapse rather than suck coolant up the height of the engine. Then when the cap is removed they revert to their original shape and such air into the system. It is all guessing to try to make sense of what has been said.

 

I agree that this topic has got very mixed up between varicose problems and engines.

 

PS - for the pendants, I know it is air pressure that would push the coolant back up, but most people can relate to "suck" more easily.

[RLWP]

1 hour ago, Peugeot 106 said:

The anti vacuum bit is the bronze coloured disc in the centre which is spring loaded and lifts when a vacuum is applied and allows air back in.  Maybe the spring is too strong? Don’t worry Richard I expect it’s your silly season though on the Thames it’s to quote lock keepers “eerily quiet”. I have a theory that no body can find competent mechanics to fix or service their engines! Good Luck

 

Could you send a picture of the cap side-on?

 

Richard

[Peugeot 106]

42 minutes ago, RLWP said:

 

Could you send a picture of the cap side-on?

 

Richard

Yes when we are stopped tonight. I’ll show it open and closed

 

1 hour ago, Tony Brooks said:

 

Having seen the photo of his set-up, I no longer think so. It is a "milk bottle" on the baseplate with a hose from the normal filler neck overflow. I am now wondering if he has some hose(s) that are very soft so as the depression develops they collapse rather than suck coolant up the height of the engine. Then when the cap is removed they revert to their original shape and such air into the system. It is all guessing to try to make sense of what has been said.

 

I agree that this topic has got very mixed up between varicose problems and engines.

 

PS - for the pendants, I know it is air pressure that would push the coolant back up, but most people can relate to "suck" more easily.

It’s 8mm id think walled fire certified fuel hose. I can’t see it collapsing under vacuum it’s quite hard walled. 
 

 

50 minutes ago, RLWP said:

 

Could you send a picture of the cap side-on?

 

Richard

Yes when we are stopped tonight. I’ll show it open and closed

 

1 hour ago, Tony Brooks said:

 

Having seen the photo of his set-up, I no longer think so. It is a "milk bottle" on the baseplate with a hose from the normal filler neck overflow. I am now wondering if he has some hose(s) that are very soft so as the depression develops they collapse rather than suck coolant up the height of the engine. Then when the cap is removed they revert to their original shape and such air into the system. It is all guessing to try to make sense of what has been said.

 

I agree that this topic has got very mixed up between varicose problems and engines.

 

PS - for the pendants, I know it is air pressure that would push the coolant back up, but most people can relate to "suck" more easily.

It’s 8mm id think walled fire certified fuel hose. I can’t see it collapsing under vacuum it’s quite hard walled. 
 

 

1 hour ago, Steve56 said:

Back in the day this is the type of header tank supplied by Lister as an optional extra for use with the Polar manifold. It would be piped up to the manifold overflow pipe. The manifold would then be fitted with a plain non pressurised cap, and the pressure cap would be fitted to this header tank. Also the original water pump fitted to that engine would have been a non bypass type, therefore it would have a standard type thermostat without the extra flap fitted. Also noticed previously mention of thermostat jiggle pin. On the set up above the jiggle pin was removed on assembly. This was to alow a small amount of water circulation before the thermostat opened. As the pump was non bypass this ensured there were no internal localised hot spots. By the time Lister moved over to the later type cooling system the engine was also being fitted with the later pump. If the pump has ever been changed the chances are it will be the later type pump as the early pumps were made obsolete but were totally interchangeable. 

Steve very helpful will be back when I’ve got my head round the change in pump design, thank you