Expansion Bottle

[Stag Beetle]

Is there any reason why just moving the expansion bottle to a higher point in the engine bay and using the original connection to the radiator is not done?

I was thinking of using a bottle like this and mounting it near the fuse box this would mean no extra pipes or connections

Any points, help in the right direction will be appreciated.


Andrew

[mjheathcote]

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No reason at all.

My 'mark 1' turret mounted header tank was plumbed that way for 20 years no problem.

My 'mark 2' turret mounted header tank is also plumbed into the top hose as well. Can't really say whether this is better or not, same running temperature.

Cheers,

Mike.

[Tdm]

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Can't help you with your posted question personally - but would be interested to see what replies you get.

However your given location intrigues me - it's not listed in my AA Glovebox Atlas - does it really exist & where is it?

Terry

[V Mad]

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Stag Beetle wrote:

Is there any reason why just moving the expansion bottle to a higher point in the engine bay and using the original connection to the radiator is not done?

I was thinking of using a bottle like this and mounting it near the fuse box this would mean no extra pipes or connections

Any points, help in the right direction will be appreciated.


Andrew

I think you are confusing the expansion bottle with a header tank. If you want a header tank you will have to do the plumbing.

[mjheathcote]

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V Mad wrote:

Stag Beetle wrote:

Is there any reason why just moving the expansion bottle to a higher point in the engine bay and using the original connection to the radiator is not done?

I was thinking of using a bottle like this and mounting it near the fuse box this would mean no extra pipes or connections

Any points, help in the right direction will be appreciated.


Andrew

I think you are confusing the expansion bottle with a header tank. If you want a header tank you will have to do the plumbing.

No depends whether you are talking early mark one stag or mark two stag.

The early mark one stag does have a true expansion bottle with no pressure cap, the mark two a header tank with a pressure cap that can also be called an expansion bottle with pressure cap...if you know what I mean!

If your bottle has a pressure cap there is no reason why you can't raise it higher with an alternative design bottle connecting to the original small bore connection on the top of the radiator only.

Thats what I did originally over 20 years ago to good effect. Before I was always topping up the originally bottle, as soon as the turret mounted tank was fitted I never needed to top up again between complete flushes.

Cheers,

Mike.

[Stag Beetle]

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Thanks for the information so far. I was thinking along the lines Mike was talking about as I have a late MRk 1 Stag with a pressure cap. I don’t have any overheating problems at the moment but thought it would be a wise upgrade as I am using the Stag on a daily basis including some motorway work and I thought it would be good to have a little safeguard to the cooling system.



Muckle Flugga[/b]is the most Northerly Island and lighthouse in the Shetlands

(It’s a lighthouse thing similar to the Kylie fixation but more nerdy).



Andrew

[V Mad]

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mjheathcote wrote:

I think you are confusing the expansion bottle with a header tank. If you want a header tank you will have to do the plumbing.

No depends whether you are talking early mark one stag or mark two stag.

The early mark one stag does have a true expansion bottle with no pressure cap, the mark two a header tank with a pressure cap that can also be called an expansion bottle with pressure cap...if you know what I mean!

If your bottle has a pressure cap there is no reason why you can't raise it higher with an alternative design bottle connecting to the original small bore connection on the top of the radiator only.

Thats what I did originally over 20 years ago to good effect. Before I was always topping up the originally bottle, as soon as the turret mounted tank was fitted I never needed to top up again between complete flushes.

Cheers,

Mike.

Mike, if you were always topping up you must have been losing water?

As you will know, (Mk2) owners often check the levels by looking only at the expansion bottle, andthe proper way is tocheck the level at the filler plug on the rad. The level in the expansion bottle is not critical, but should not be more than half full to avoid coolant loss.

To improve the Mk2 Stag cooling system, you need to have a proper header tank fitted as high up as possible. The header tank should have two pipes, to allow flow and return of water. The tankserves to:

1. Ensure that there is a reserve of water above the engine levelin case of amoderate loss.

2. Provide a reliable visual indication of water level in the system.

3. Serve as an effective filling point.

If you simply raise the expansion bottle to a higher point, then due to the small bore pipe, that goes into the radiator, air locks will occur (there is nowhere for the air to escape exceptback up the pipe)and it will be difficult to fill the system. The level indication may be misleading due to possibilty of air locks. As there is no flow in the tank the addition of antifreeze will not mix fully.




Andrew, you certainly have chosen a remote place to take the Stag. Is it a problem getting parts delivered?

Do you have traffic free roads? I spent a weekend in mid Wales with a couple of Stags, and it was great, we had the roads to ourselves.

[Stag Beetle]

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:P

[mjheathcote]

imported post

V Mad wrote:

mjheathcote wrote:

I think you are confusing the expansion bottle with a header tank. If you want a header tank you will have to do the plumbing.

No depends whether you are talking early mark one stag or mark two stag.

The early mark one stag does have a true expansion bottle with no pressure cap, the mark two a header tank with a pressure cap that can also be called an expansion bottle with pressure cap...if you know what I mean!

If your bottle has a pressure cap there is no reason why you can't raise it higher with an alternative design bottle connecting to the original small bore connection on the top of the radiator only.

Thats what I did originally over 20 years ago to good effect. Before I was always topping up the originally bottle, as soon as the turret mounted tank was fitted I never needed to top up again between complete flushes.

Cheers,

Mike.

Mike, if you were always topping up you must have been losing water?

As you will know, (Mk2) owners often check the levels by looking only at the expansion bottle, andthe proper way is tocheck the level at the filler plug on the rad. The level in the expansion bottle is not critical, but should not be more than half full to avoid coolant loss.

To improve the Mk2 Stag cooling system, you need to have a proper header tank fitted as high up as possible. The header tank should have two pipes, to allow flow and return of water. The tankserves to:

1. Ensure that there is a reserve of water above the engine levelin case of amoderate loss.

2. Provide a reliable visual indication of water level in the system.

3. Serve as an effective filling point.

If you simply raise the expansion bottle to a higher point, then due to the small bore pipe, that goes into the radiator, air locks will occur (there is nowhere for the air to escape exceptback up the pipe)and it will be difficult to fill the system. The level indication may be misleading due to possibilty of air locks. As there is no flow in the tank the addition of antifreeze will not mix fully.




Andrew, you certainly have chosen a remote place to take the Stag. Is it a problem getting parts delivered?

Do you have traffic free roads? I spent a weekend in mid Wales with a couple of Stags, and it was great, we had the roads to ourselves.

Having a flow and return is a better option, infact that is what I have now.

However not having a flow and return but still having a head of water higher than the water pump is better than the original bottle position however.

Why I used to keep on topping up, then never again with a higher tank I do not know. It was actually 22 years ago now!

[stoutgoose]

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I'm using a Rover V8, with a small bore pipe (to act as an air bleed and expansion pipe) from the highest point in the top radiator hose running down into the Stag Mk2 expansion bottle. This is effectively from the high pressure side of the system.

I also have a narrow bore hose running from the top of the radiator on the other side (lower pressure side) acting as an air bleed to remove air from the top of the radiator.

These hoses are joined together with a T-piece before feeding into the bottom of the standard expansion bottle via a single pipe.

Can this set up cause any issues? The reason I ask is that the system seems to develop up to about 15psi pressure in it (measured with a cooling system pressure tester on the expansion tank). Hoses are moderately hard but not excessively,and the level in the expansion tank with the cap on (15psi) rises about 1.5 to 2 inches between cold and hot, however it does not rise any higher than this and does not vent.

There is no over-heating (temp reaches 92 then fan kicks in), yetafter havingrecently plumbed in another expansion cap into the top hose I have noticed that after re-filling the system and purging it of air, there has been some evidence of water being pushed out of this top hose expansion cap, but not from the expansion bottle (the level of which does not rise excessively).

When running the engine with the cap off the expansion tank and with it raised above the top hose, water level in the bottle continues to rise to over-flowing (when bottle was 1/3rd full at the start), but level drops back down when electric fan cuts in, and pressure reduces.

I've carried out several tests for head gasket failure and dropped liner problems, but there is no evidence of either (both block tester fluid and looking for bubbling in water). I'm wondering, having read your comments about high and low pressure sides, that I might have made some kind of fundamental error in this set-up?

Lastly, do you know what kind of pressure would be normal in a cooling system running at 90 degrees centigrade?

Any ideas or experiences appreciated.

[Stagdad]

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Stag Beetle wrote:

Is there any reason why just moving the expansion bottle to a higher point in the engine bay and using the original connection to the radiator is not done?

I was thinking of using a bottle like this and mounting it near the fuse box this would mean no extra pipes or connections

Any points, help in the right direction will be appreciated.


Andrew

I know many have used the original expantion pipe to good effect when fitting a header tank but i still think you cant beat gravity to do it's thing with the system.A pipe off the bottom of the header tank going down to a low point in the rad and a pipe coming of the highest part of the rad letting any air out of the system to collect out of harms way in the header tank .that way you know the system is full with no airlocks ,

[Stagdad]

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A picture says a thousand words

Steve