MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - MGA radiator over flow/recovery tank

My 1956 A overflows a lot of coolent as it tends to get hot often. I would like to try the over flow collector tank that has been talked about on this threads/page. does anyone have an extra I could purchase from and try it out? At this point either one sounds ok. I purchange a fan for my MGA but have not installed it as of today.
Tom
Tom Peotter

You can find overflow tanks at any auto parts store. connect the hose from the bottom of the overflow tank to the over flow tube from the radiator fill neck. If you have a very old pressure cap you may need to buy a new one that has the valve built in to the pressure cap to allow the coolant to return when the engine cools.
John H

Look on Ebay
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=005&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=150133742823&rd=1,1

This on sold for only $38
Jones

Just contact one of the used parts suppliers that are advertisers on this board. They will sell you one with a bracket for $30 or so, shipping will cost you about $10 to the USA.
dominic clancy

Several years ago I bought this cute octagonal bottle in a coolant recovery kit frmm Pep Boys for under $10 total. See here: http://mgaguru.com/mgtech/cooling/cool_204.htm
Barney Gaylord

I say one at Pep Boys this weekend for $7.99 It will wor just get it higher then the Rad.
Jones

We have been trying to stress the point that the tank does not have to be higher than the radiator. Whether it is a coolant recovery tank vented to the atmosphere, or a pressurised expansion tank, it does not have to be higher than the radiator.
What is important is that the water pipe (or tube) in the remote tank goes almost to the bottom of the tank, or the connection is at the bottom of the tank (same result).

Mick
Mick Anderson

thank you all for your responses, I'm going after the one on e-bay
Tom Peotter

Hey Barney - an octagonal rad cap as well - how cool is that! - cheers Cam
Cam Cunningham

OK OK I saw a coolant recovery tank on a 55 Olds (Not a MG but the same principle?) this morning it was infront the rad. & 1/2 down. I asked if it worked, he said he adds coolant to the rad. every time he drives the car. so what did he do wrong?
Jones

If he is adding coolant all the time he either has a leak or his lone to the expansion tank is connected to the top where it can't siphon the coolant back when the engine cools. The tank on our A is mounted under the front duct panel behind the front valance. On a stock MGC the expansion tank is mounted on the frame rail below the radiator
John H

John,

The message that you intended is correct, but you used the wrong word. It is not a siphon action. In a siphon the level of the liquid in the "from" tank must be higher than the level of the liquid in the "to" tank.
When the water in the radiator cools it contracts. This reduces the pressure in the radiator to below atmospheric pressure. With the vented type remote tank the atmospheric pressure pushes the water back into the radiator to bring them both to atmospheric pressure.
In the pressurised remote tank the pressure pushes the water back into the radiator. If the pressurised type remote tank has a correct double valve and upper seal type cap the radiator and the remote tank will both finish at atmospheric pressure.
Therefore the remote tank can be lower than the radiator.
The critical point is that the remote tank return pipe must come from the bottom of the remote tank.

Mick
Mick Anderson

The only critical part to make a coolant recovery tank work is a proper type cap. The original cap on left has a brass "seal" at the top and no internal valving. The recovery cap has a rubber seal to seal the top of the radiator neck like the small cap on right. With the proper type cap all you need is a hose that goes to the bottom of a bottle. Any bottle that fits anywhere will work.


R J Brown

Yes, the cap required must have a seal at the top of the radiator neck. It should be mentioned that the cap must also have the small return (inlet) valve in the center, as shown in the photo.
The real problem is to find a correct cap which is suitable for the deep MGA radiator filler neck. If a long type cap cannot be found you need to fit a short filler neck from a modern car. Any radiator shop could remove a short filler neck from a junked radiator and fit it to a MGA radiator.
(These comments refer to the vented type remote tank only).

Mick
Mick Anderson

Has any one tried making a rubber washer to seal the radiator cap to the radiator neck and using a standard cap? I am in the middle of installing a vented type overflow tank and have made a washer with part of an inner tube. Hopefully it will work, I should know tomorrow!
Keith Morris

Keith,

What are you trying to do? A vented overflow tank, using the coolant recovery system, requires a cap on the radiator with the small inlet valve in the centre. Does yours have that?

Mick
Mick Anderson

Yes it does have the poppet valve in the centre. I think they all do as even in a non-recovery system the cooling coolant will shrink and the cap needs to allow air to enter the expansion tank.
Keith Morris

Keith,

It will take several cycles from cold to hot and back to cold before you can be sure it is working. It has to cycle several times to remove all air from the system. Start with the radiator as full as possible and the remote tank about half full.
Ensure that the connecting hose goes close to the bottom of the remote tank.
What material is the remote tank? If it is plastic you can get a good view of what is happening. If the level rises when hot and drops when cold, you never have to remove your radiator cap again. The radiator MUST be full for that to happen.
Removing the radiator cap just lets air into the system.
If the remote tank is metal, using a flashlight to check the level can be misleading, an optical illusion can confuse you about the level. Use a wooden dipstick.

Mick
Mick Anderson

Putting a rubber washer on a standard radiator cap to seal it to the top of the neck does not work. Coolant escapes between the metal disc and the radiator cap top - pretty obvious it will with hindsight.

Plan B is a 6mm (1/4") rubber washer inserted into the radiator neck before a recovery type short neck radiator cap is fitted (see about half way down on http://mgaguru.com/mgtech/cooling/cool_204.htm ). This looks like it is going to work but I have a leak in the solder joint between the radiator neck and the overflow pipe which I need to fix before it will work properly.

Mick, the tank is a plastic one made by Haigh and sold by Autobahn quite cheaply with some pipe a clamp etc. It fits quite nicely against the right inner wing in front of the radiator and is small enough that it won't impede airflow through the radiator.

Keith Morris

As I am contemplating this mod, does anyone have a part number from a mainstream manufacturer that I can use to get the correct cap for the radiator?

Mine too will have to go in front of the rad (Supercharger pulley ocupies the spot that Steve uses), and I'll be using a brass tank from an midget. Just ned to get a mounting bracket for that too.

dominic clancy

Having fixed the leak between the radiator neck and the overflow pipe the system now works - thanks Barney for the idea!

Dominic, if you are going for a vented overflow tank you will be lucky to find a suitable radiator cap (none available in Australia as far as I know though of course there may be in Switzerland). Have a look at the link in my previous post, Barney Gaylord did find a Napa radiator cap that may suit.

If you are going for a pressurised system then the cap on the radiator needs to be a blank to seal the radiator which should be relatively easy to find and the cap on the brass midget tank will need to be a 7lb cap to suit - I don't know whether the midget tank is long neck or standard.
Keith Morris

This thread was discussed between 25/06/2007 and 01/07/2007

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.