Expansion Tank

Dave3066

Dave3066

Well-Known Member
My project for this weekend has been to finally fit the expansion tank I bought a while ago. I've been slowly collecting all the bits I need and painting the tank ready to fit and the onset of some warmer weather 8) has prompted me to get it done.

Here are the bits:

CIMG3222.jpg


The tank is an old brass Land Rover Tank which I toyed with the idea of cleaning and polishing but settled for a couple of coats of hammerite. The 2 disks on the tank are cork spacers to prevent metal on metal contact when it's fitted. The strap is an old fuel tank retaining strap cut to size. The rest is self-explanatory.

Here is the space it will occupy:

CIMG3223.jpg


I offered the tank up to the space and positioned the strap to figure out where to drill the fixing holes. Then it was simply a matter of drilling and fixing the tank with a couple of bolts. I'd got a length of coolant hose with the tank so I attached that to the radiator overflow and put the old overflow hose on the expansion tank overflow. I filled the radiator to the top and burped it a few times by squeezing the top hose and kept topping up until the coolant was right up to the brim. Then I put the blanking cap on the radiator and started the car. I kept feeling the link hose to the expansion tank so I knew when coolant was flowing into the tank (the hose got warm) and watched as coolant rose in the tank. Once I'd got coolant into the tank I filled it halfway with fresh coolant and put the pressure cap on. I ran the car for a while to check the operation of the tank and then switched the engine off and let it cool sufficient to take the pressure cap off safely. I topped up the coolant further, replaced the pressure cap and left it until this morning. When I checked the coolant level in the tank it was about halfway so I knew it was working :D result. Here is the final installation and it didn't take long at all.

CIMG3224.jpg
 
These are my favourite tanks. They suit the cars, got them on our 110, Bruiser & have another to fit to our P5B. Will eventually kit them all out as I now consider it an easy & essential addition to any car.
 
That is just what I am looking for ... fits well and look almost factory. What year Land Rover is this out of? Are they available new? I have set my sights on this now as it looks the part ... mine is an evian bottle at the mo :wink:

Have a plastic SD1 on the shelf, but not really suitabel as has a number sightly electronic terminals on it, which would be redundant, hence unsightly.

Let me know, cheers Jim
 
TwinPlenum3500S said:
That is just what I am looking for ... fits well and look almost factory. Have a plastic SD1 on the shelf, but not really suitabel as has a number sightly electronic terminals on it, which would be redundant, hence unsightly.

Let me know, cheers Jim
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Why not wire it up to a temp warning light!
I fitted a white one,as its easy to see the level without opening it! :wink:
IMAG0687.jpg
 
Pilkie

Ill have a fiddle about and see if I can get it to fit ... just dont want ugly made up bracketry, or things that look out of place... (not that yours doesnt look good, becasue it does)

Bar my lashed up, get out of trouble bottle, my bay looks outstanding at the moment, all the plenum chamber painted and the ally fins polished and lacquered, same treatment for the vitesse rockers, with new Rover stickers, painted injectoin rails, inlet manifold, front cover, Y peice, afm, new plenum hoses etc etc etc ..... then a clunky old white bottle with two big winged screw holes and a load of meccano brackets.

I was seriously thinking to have an ally one made that moulds to the contours of the inner wing, with bespoke fixing brackets ... I may still do this.
 
I found this article regarding the fitment of an expansion tank. For cars fitted with a conventional radiator such as what we have in the P6, the article states that the tank will achieve very little, except for providing a catchment for coolant that would otherwise spill onto the road when the engine is hot. This of course from an environmental perspective is a good outcome.

Thinking about it, how could coolant within the expansion tank possibly flow back into the radiator when the pressure within the radiator is greater?

When the system is cold and the pressure is in equilibrium between the radiator and expansion tank, how does coolant flow from the expansion tank into the radiator when the radiator cap is closed?

Do you fit your expansion tank in the knowledge that it will act as a coolant overflow catchment only? That you will still need to top up your radiator either with fresh coolant or by removing the expansion tank and pouring the coolant within back into your radiator as regularly as you have always done.

Expansion tank article......http://www.custompistols.com/cars/articles/overflow.htm

Ron.
 
They kind of did.. This is from my RHD NADA, and shows where the factory placed the expansion tank, and how.
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That's interesting Chris, but do you think it's original? I've never seen one there before, even on a NADA as most of them seem to have a charcoal canister there. Although yours may well have been a tad 'experimental' :) Was it a factory owned car originally? Does it have the emission control guff?


Thinking about it, how could coolant within the expansion tank possibly flow back into the radiator when the pressure within the radiator is greater?

When the system is cold and the pressure is in equilibrium between the radiator and expansion tank, how does coolant flow from the expansion tank into the radiator when the radiator cap is closed?
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You need to fit a recovery cap to the radiator. When the radiator heats up, the coolant is forced out in the usual fashion but instead of landing on the road, it goes into the bottle. When the radiator cools down again, the valve in the recovery cap allows coolant to be drawn back in from the bottle.
 
KiwiRover wrote,...
You need to fit a recovery cap to the radiator. When the radiator heats up, the coolant is forced out in the usual fashion but instead of landing on the road, it goes into the bottle. When the radiator cools down again, the valve in the recovery cap allows coolant to be drawn back in from the bottle.
Click to expand...

Hello KR,

Yes I do remember when I considered fitting an expansion tank in the late 1980s that the instructions on the box said that a rubber gasket had to be placed beneath the radiator cap,..or something along those lines.. :? I didn't like that idea so I never fitted one. I always had to top up the radiator when the original 3.5 lived there, but with the 4.6 the level never changes and in the almost 3 years since installation, topping the radiator up as a result of coolant loss has never been required.

I wonder if those owners who have fitted the expansion tank have also fitted the recovery cap to their radiator?

Ron.
 
Hi Ron the recovery caps have a second negetive pressure valve centrally located in the cap and work on the vacuum created in the main tank to open it.
Bugger the environment when it comes to the usefulness of the recovery system, what I feel is of more concern is that every time the expanded fluid is discharged and you top up your main tank you are effectivly diluting the coolant additive and hence raising your freeze temp and lessening the anti corrosive benefits to your alloy block and heads.
In practice with my 24 year ownership I have found that you dont really need to add water as long as you accept that the level in the main radiator is always going to be 2 inches down from the neck.

Graeme
 
ghce wrote,..
Hi Ron the recovery caps have a second negetive pressure valve centrally located in the cap and work on the vacuum created in the main tank to open it.
Bugger the environment when it comes to the usefulness of the recovery system, what I feel is of more concern is that every time the expanded fluid is discharged and you top up your main tank you are effectivly diluting the coolant additive and hence raising your freeze temp and lessening the anti corrosive benefits to your alloy block and heads.
In practice with my 24 year ownership I have found that you dont really need to add water as long as you accept that the level in the main radiator is always going to be 2 inches down from the neck.
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Hello Graeme,

Thanks for that... :) When I had to top up the radiator in the past, I would do so with some coolant that I had ready mixed. I always used to carry a container with a few litres mixed ready to go in the boot.
When the engine was my original 3.5, the level would fall over time until at least half the radiator was empty,..if I left it that long for what ever reason and forgot to top it up, but usually I would catch it well before that time. With my 4.6 the level with the engine off and the coolant cold is always right at the base of the filler neck. When I start the engine the level will fall usually by about 1cm at most and that is how it stays, the level just does not change which is really excellent. As to why the 3.5 would force coolant out, I can only put it down to increased engine temperature as a result of the 10.5 : 1 CR, timing at TDC which is most inefficient and maybe hot spots within the cylinder heads as a result of the timing. There was no suggestion of engine problems which may have been a factor,..such as coolant ending up in the oil.

Ron.
 
I have found with mine that it invaraibly falls to 2 inchs below after a run and stays there however on the odd occasion (i think only 2 or 3 times in 24 years) it drops to some much lower level in fact about 12 months ago it dropped for no reason to below the height of the water pump to much protest when i started the engine, refilled and it did not re-occur again :?: :?: god knows why. I can certainly see the desire for an expansion tank and may yet fit one......just because you can :LOL:


Graeme
 
Interesting to know this wasn't a standard fit feature, mine has one - of a particularily inelegant plastic carton design on a bracket hanging off the inner wing which looks a bit of a mess.

I'll need to check out if i have a recovery style cap on the radiator for if it is actually serving much of a purpose or not, but if not i'd probably be tempted to remove the tank and fit a water level/coolant alarm sensor like i have in my TVR and Discovery to give an audible alert if the level ever drops greatly.

Cheers,

Al
 
KiwiRover said:
They kind of did.. This is from my RHD NADA, and shows where the factory placed the expansion tank, and how.
Click to expand...

That's interesting Chris, but do you think it's original? I've never seen one there before, even on a NADA as most of them seem to have a charcoal canister there. Although yours may well have been a tad 'experimental' :) Was it a factory owned car originally? Does it have the emission control guff?
Click to expand...

It's original. My car was built as a standard LHD NADA, and then delivered to Rover's Engineering Dept where it emerged several months later as a RHD NADA, and was then the personal car of Sir George Farmer for a while, registered as ROV1. It has a few unique bits, such as a pull handle on the rear drivers' side door, so that he doesn't have to reach down to the armrest..

The dual braking system was removed, as was the emission control system. There were about six of these built, from what I've been told. We've found one other, so we're trying to get a look at it to see whether that has the same mods that mine does.
 
Don't know about recovery caps. Mine have blanking caps on the rad, no pressure fitment at all so the water is free to flow into the expansion tank at will & back to the rad again when the pressure drops. The original pressure cap is on the tank. I fit them mainly to catch the coolant as anti-freeze costs money & I don't like leaving money behind me on the motorway. :LOL:
Any added help to the cooling system/enviroment is a bonus but not my main aim.
 
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