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MG MGA - Coolant overflow tank

I've just fitted a coolant overflow tank to my Coupe using a 2" dia x 10" long stainless steel tank. This tank fits very neatly behind the radiator and attaches to the radiator mounting bolts with angle brackets that come with the tank with a small modification.

The metal overflow tube that is attached to the side of the radiator is connected to a tube at the bottom of the tank with rubber tubing.

Total cost less than $25; search for stainless steel overflow tank on eBay and you'll find several suppliers.

Andy
1960 MGA Coupe

Andy Preston

Andy..Looks neat and well made!! but Not sure from your description whether the overflow tank is pressurised or non-pressurised. The cap looks like a pressure cap but you mention the overflow from the radiator is a hose. Please expand ...
Neil Ferguson

WOW Andy! Looks awesome!
Is the tank cap sealed open to ambient or pressure release? Do you keep the pressure release cap on the radiator?


Gotta put THAT on my Christmas list... WAIT! My birthday is next Tuesday...


Honey! Got a minute????


I... uh... gotta go... talk... to the wife :)
Michael Caputo

Neil

It wont fit on your car, there's a pulley in the way from the Judson.

A maller one might just fit in front of the radiator though. pity Iť got a radiator blind in the way there too!
dominic clancy

Looks very neat - the ones on ebay like yours are either in USA or Australia. The USA ones are £21 or so but postage is £35 - so that's out. Will have to see if one comes up over here although there is a UK one it is not as tidily finished.
Cam Cunningham

Neil it's a non pressurised system, the cap is a leak free fit so it won't spill but there is a small overflow tube inside the tank that goes to atmosphere. So the radiator is pressurised to 7 lbs and the tank is not. However when the radiator cools down it does suck coolant back in the radiator so it's always topped up.

Andy
Andy Preston

Dominic......I have a modified plastic washer bottle ..and moved it from behind radiator to in front when I put the Judson in . It works well but does not look as good as the one Andy installed.
Neil Ferguson

FWIW Andy Preston's photography is on the cover of the newest issue of "MG Kurier" the German MG magazine.

Still saying congrats Andy!
Michael Caputo

One of the main advantages of an overflow system is that you are able to see the coolant level if you use a see through plastic container.
Being able to see the coolant level rise and fall when the coolant heats and cools is proof that the radiator is 100% full.
I suppose that you can check the level by removing the cap on a steel container and still not release the pressure in the radiator.

Mick
M F Anderson

Michael thanks for noticing my photo. I was driving back from Breckenridge Colorado MG 2009 on Hwy 50 (the loneliest highway in the world). My son was driving the B and I was passing time by taking photos and came up with this one that won the German MG competition.

Thanks

Andy

Andy Preston

Well done Andy! Can you tell us a bit about what camera? - shutter speed? etc. etc.
Barry
Barry Gannon

I have put up with not having an overflow tank on my MGA'S by letting the level go down and trying to remember where it was. My cars are "original", a curious "fetish" of mine.
Barry Bahnisch

Andy, could you please email me some closer shots of the overflow tank?...I've purchased one, and just want to see your connections (not clear on the original photo). Also, I want to see at what level the top of the bottle is.
Thanks
Gary
Email: lock@winshop.com.au
Gary Lock

Gary,

The level of an overflow tank has no relevance to the operation.
It can be above or below the water level in the radiator.
The expanding water in the radiator will push the overflowing water to any reasonable height (up or down).
The returning water is pushed from the overflow tank by atmospheric pressure and again any reasonable height is OK.
Are you using the system where the radiator cap is a blanking cap only and the pressure cap is on the overflow tank?
Or are you having the pressure cap on the radiator and the overflow container open to he atmosphere?
In the first case you need good hose clamps and a hose to hold pressure.
In the second case the fittings and hose have much less importance in specification.
Is your overflow tank transparent?


Mick
M F Anderson

Hi Gary I hope this larger photo helps a little more.

The lower chrome L shaped bracket (that comes with the tank) is attached to the second radiator bolt from the bottom and to the lower tab on the tank.

The 2 tabs on the tank don't line up with 2 radiator bolts. So with the top tank tab I used a small length of aluminum flat bar to connect it to the next lower radiator bolt using the other chrome L bracket.

I'd guess that the top of the tank is level with the top of the radiator but the coolant level inside in about 2" lower.

I connected the radiator overflow tube which is at the bottom of the radiator to the tank with some rubber tubing.

I noticed recently that the overflow tank was full so the collant was not sucked back into the radiator as it should be. I'll check the radiator cap and see if the rubber tubing that I used is not too thin and collapsing when hot and under vacuum.

Andy

Andy Preston 1

Andy,

You need to check that you have the right type of radiator cap for an overflow system.
It must have three rubber seals.
One seals the outer edge of the cap to the top edge of the radiator neck.
One seals the the cap to the rim edge at the bottom of the radiator neck (spring loaded).
One is a small rubber disc in the center of the cap that opens inwards.

I assume that the atmospheric air can enter the overflow tank via an open hole.

This shows the advantage of having a transparent overflow container so that you can watch the level rise and fall during the hot/cold cycle.

Mick

M F Anderson

Andy, thanks for that...much clearer.

Mick, I already have a recovery system, using the Mini/others brass tank situated on the bulkhead panel next to the washer bottle, but I like the look of this container better.
Gary Lock

Mick, thanks for the radiator cap info. I'll check mine out and the overflow tank has an open hole to atmosphere.

Thanks
Andy
Andy Preston 1

Andy, I would presume that the atmospheric air would enter the tank via the overflow pipe from the tank itself?
Gary Lock

No. You can check their web site. As I understand it, the tank has an o-ring sealed cap and two tubes out the bottom. One tube is connected to bottom of the tank, and that will get connected to the radiator, which will have a recovery type pressure cap. The second tube extends inside the tank up to very near the top (like a soda straw), and that one serves as the breather and overflow for the tank. The tank is therefore vented and non-pressurized. It is just a convenience that the vent tube at top of tank extends out the bottom rather than coming out the side near the top. It is a styling gimmick, space saver, and kind of neat.

Barney Gaylord

Barney you are correct; that is exactly the set up with the overflow tube coming out the bottom of the tank which is very neat. As I said in one of my posts I'm not recovering coolant from the overflow tank so I assume that my radiator cap is at fault. Is the Moss radiator cap the recovery type.

Thanks

Andy
Andy Preston

I don't know about the Moss part, but you can get a recovery type cap a any local auto parts store. The short neck ones for later cars are very common and in stock everywhere in any pressure rating you like. The long neck one is not always in stock everywhere, but any store should be able to order it up in a jiffy. Some common part numbers for 1-inch reach and 7-psi are:
Balkamp 703-1411
Stant 10206
These are available at NAPA. I don't have cross reference to other manufacturer numbers yet. The one thing to look for is the rubber seal around the top ring for recovery type caps.

Barney Gaylord

Off topic, but has anyone tried a radiator cap as shown in the attached image?
I suppose it is meant for cars that do not have a temperature gauge.

Mick

M F Anderson

I use a plastic overflow bottle from a 1968 Volvo P1800

I found it at a junk yard. It fits just like Andy's as it is about three inches in diameter and 10 to 12 inches tall. It is pressurized with the 7lb.cap I took off the radiator. A blanking cap is used on the radiator.

A quick visual check is all that is needed to verify that I have coolant. It has worked perfectly for several years with no loss of coolant. Now my car marks it's territory with oil drips.

I would think that other Volvos of that period would have the same tank. It is not as pretty as Andy's but it works great.

Tom
T. P. Panagos

Tom,

Having coolant in the overflow tank does not indicate that the radiator is full.
Only the rise and fall of the coolant level in the overflow tank during the hot/cold cycle proves that the radiator is 100% full.

Mick
M F Anderson

Andy,

Did you get your overflow tank/radiator to suck the overflow back into the radiator when cooled? What cap did you use and what type of hose?

I have recently fitted the same s/steel tank but it does not appear to be creating the vacuum or drawing the coolant back into the radiator.

How is yours working?

Ian
I B Morris

The 7 psi Radiator Cap that I am using is 1 1/8 inch from top of cap to bottom rubber seal. It also has the rubber seal at the top radiator neck and the disc "valve" at the bottom.

Ian



I B Morris

A common fault that I have found is the area where the metal overflow tube fits into the radiator neck.
They can be a press fit sometimes with no soldering or brazing.
The tube can be loose and leak air during the suction cycle.

Mick
M F Anderson

Think you may have nailed it, Mick.
The solder around the top edge of the overflow tube connection was cracked. I have fixed that up & will now see how it goes.

Ian
I B Morris

Also ran a flat file across the top of the radiator neck seat surface where the rubber seal sits. It was a bit "wobbly", but filed down flat.
Now it's working like a beauty!!

IBM
I B Morris

Ian I bought the Stant cap 10206 as recommended by Barney. I've only driven the car once since then (it's raining in California) so I can't say for certain but the new cap was slightly deeper than the old one.

I'm pleased that your system is working so I anticipate that I can get mine to work as well.

thanks

Andy
Andy Preston

This thread was discussed between 08/11/2012 and 17/12/2012

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