Which Expansion Tank?

[Guest boggie]

Hi all,

I am off down to the scrappy soon in hunt for a coolant expansion tank. I guess it needs to be tall and thin and someone suggested a micra unit. I have tried a modified bicycle water bottle but that was not up to the job. So if you have successfully fitted and run (without loosing any coolant!) an expansion tank from another car please let me know which one you have used as I am lending the car to my girlfriend and I don't want it to leave her stranded!

Cheers, Boggie

[Guest johnboymac]

I have seen people using a 1 litre antifreeze bottle as an overflow (had thought about this for myself, as I want to preserve space in the nosecone area for airflow!) but not sure if this is suitable or not.

John

[Guest Ant]

Find a 2.0 capri in a scrappy and you'll find an expansion bottle perfect for the job - fairly small, sensibly shaped, two mounting lugs, and already connected to the pinto in the Capri in exactly the way you do it with a hood. A hole in the top for filling it, and a single outlet in the bottom to go to the radiator overflow pipe.

 

Perfek!

 

Ant

 

PS - photo on my website ... pic 1 and Pic 2 (To the left of the blue timing belt cover).

[Guest boggie]

Cheers Ant,

I notice that this is not a pressure cap version, is it possible to use one or is it not worth it? I have at present got a 1 litre water bottle connected in the same way but the car still blows water off but it doesn't seem to overheat so I guess it is just expansion of the water as it gets hot. It always needs a top up in the rad after each journey.

Boggie

[Guest Bernie]

If the water level in the expansion bottle is kept above the bottom of the pipe from the rad cap expansion outlet then, as the engine cools, coolant will be drawn back into the system via the vacuum relief valve in the cap. Thay's always assuming the correct type of rad cap has been used.

 

There is another discussion on this topic somewhere in this forum where excellant detailed drawings were also posted.

[Guest boggie]

Hi Bernie,

Yes I saw the thread, in fact I think I posted in it.

I followed the instructions by using a bike water bottle but it hasn't helped I am afraid. It works in theory but I need a better tank. What did you use?

Boggie

[Guest Anthony B]

Hi all

 

I used one from a Nissan Primera which is tall and thin, has the inlet in the bottom and a curved outlet at the top. I have had this on since about April and it seems to work very well.

The only tricky bit was fabricating a cage for it to sit in and bracket back to the side members, just above the alternator.

 

HTH

Ant

[Guest Tim Norman]

Can't remember excactly but I think mine came from a Maestro. It has a pressure cap, big outlet at the bottom which feeds the bottom of the radiator via a T piece and has a return from the highest point of the upperhose to take out any air and allow a bit of water through if it all gets too hectic. I'l try and sort some photo's out.

It's mounted on the bulkhead by the battery. with the rad as far forward as it can go int he nose.

 

Cheers

 

Bobsmate

[Guest Mr Pid]

I robbed one off a metro in the scrappy, it is nice and compact. It has an outlet at the bottom which i will connect to the rad pipe. It is a pressurised unit but by leaving the hose off of the top outlet, it makes it able to breathe.

 

Havent found anywhere to put it yet- that is my next mission!

 

Good luck

 

Stu

[Guest mark kingston]

Mine came out of a Mazda 323 and is nice and square with two flanges with holes to mount and just goes staight in with no mods needed, the car has been on the road 2 years now with the expansion tank mounted to the side tube in the nose cone area with no problems.

regards

Mark kingston

[Guest Bernie]

I used a simple washer bottle picked up at one of the shows. I'm not on the road yet but the car, 2.0 L carb, has been run quite a few times now without any obvious problems. The longest period of continuous running is probably in the order of thirty plus minutes, enough time for the electric fan to cut in and out several times. I currently have a thermostat element fitted which is rated at something like 85/88 and electric fan. I would like something which kicks in a little lower as the temperature gauge does hover a bit towards the red end but still in the blue. It's something I can live with and the temperature will anyway probably sit a little lower on the scale once there is air flow through the rad from forward motion. Only a petrol tank to source and I can think about SVA.

 

The only problem I had with the water system on mine was that the highest point in the system is the return side from the heater matrix back to the pump. There was a tendancy for an air lock to form in that pipework with the resultant loss of flow in the circuit from inlet manifold to heater matrix and back to the pump. The water in the head therefore hit boiling point and then forced an excess of water, and if left too long steam, out of the expansion tube into the bottle. Once lost as steam that volume was lost forever.

 

To get over this I fitted a "T" piece into the heater return pipe with a threaded plug in it to enable the water to be topped up there. Since that modification I've had no problems at all.

 

The theory therefore appears to work in practice for me so maybe we're looking for something else causing you the problems of water loss. One other possibility I can think of, apart from the air ock theory, is that there may be a small leak especially in one of the return circuits which doesn't pass water out under normal circumstances but can suck air in when cooling instead of drawing water back in from the expansion bottle via the vacuum relief valve.

 

I hope that these ramblings give you something to work on.

 

Happy plumbing.

[Guest Ant]

With my capri bottle as described above, I've now done 2500 miles without needing a top-up. I check the level regularly, but it doesn't move. When the engine is running it changes level slightly as I'd expect, but once cold it's always back to the mark where I filled it to.

 

If you already have a non-pressurised expansion system similar to mine, but you're losing water, then I suggest you check out the top-most seal in the radiator cap, and the hose connections to the expansion bottle. If they're all ok, then it could be a slightly weapy cylinder head gasket perhaps? That's a bit extreme, but it's the only other explanation really. One expansion bottle is much the same as another if the pipe from the rad overflow is below the water level and you've got 1/2 a litre or more of water in it.

 

Ant

[Guest Kev H]

Cortina expansion tank as described in Dave Andrews article in the 'Downloads' section of the RHoCaR main site works a treat.

You have to hunt about a bit to find a Cortina though

 

Kev

[Guest gordon_macnab]

I used one from a Renault 19. easy to remove and re-use the mounting frame too which it attaches to with a simple rubber bungee

 

Gordon

[Guest Angel Boy]

One from a Volvo. It is a fat cigar shape with feed at the bottom and radiator overflow at the top. Got the idea from John Waterman ( I think my memory is getting fuzzy these days), so thanks John, works a treat

 

Andy