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MG MG Y Type - Radiator level

I am relatively new to old cars, having had my YA for about 5 months now. I have been to quite a few shows in it without incident. Before each journey I always take off the radiator cap to check the water level, and there is always some water visible in the filler neck. Assuming that some water must have been used, I top up the level with distilled water. Recently I have noticed that after a run it leaves a small puddle of water on the drive, although the actual level doesn't appear to have gone down. Can anybody tell me (as a novice) whether I should be checking the level in a different way, or where the apparent leak may be coming from please?
Andrew Adamson

If you can see the water in the neck of the radiator when cold, Andrew, I do not think you need to worry. What you will see ejected at the end is the "expansion" element of over-filling. Check it and if you can see it, don't add. Always take a bottle with you for emergencies - if you don't need it someone else will!

Paul
Paul Barrow

I've come to the conclusion now Andrew that if I stick my finger down into the radiator neck and my finger tip hits water, there's enough in there (when cold obviously!). If I stick more water in there for good measure (which I did regularly early on) the car spends the next few minutes at the first set of traffic lights disposing of it down the radiator overflow pipe! Hope your mind is put to rest....

Ken
Ken Jones

The trouble is that everyone is used to modern sealed, pressurised systems. The 'Y' Type system is a pre-war Morris 'unpressurised' one, and so is open to atmosphere all the time. It will evaporate slowly, and if you over-fill it, it will just expand out of the overflow pipe. The bottom of the 'neck' of the filler is the top of the header tank, so if you can see it, there is still a huge reserviour in the tank. It will 'expand' quite a lot when you stop, due to there being no flow to cool inside the cylinderhead. If you had a Calorimeter fitted to the radiator cap, ( a temperature gauge) you would see that under normal running the needle is between 'hot' and 'normal'. But when you stop, all the hot water rises to the header tank and the needle will go right over to almost 'boil', with the engine not running. Hot water rises as it has a lower SG than cooler water. It also expands, hence the engine dumping a bit after your run. If you keep topping it up, it will do it again...

Neil.
Neil Cairns

The T series cars have the same unpressurized cooling system (except for the TF). I built and installed a coolant recovery seytem for our TD and since then, the coolant level remains right at the top of the filler neck (even with the top of the overflow tube) all the time. Any coolant expelled from expansion is sucked right back into the radiator header tank as it cools. Anyone interested in such a recovery system, e-mail me and I'll send you a write up and pictures of the system.
Cheers - Dave
David DuBois

Thanks David, I think the Aussies have already filed something on this - see Hints and Tips, but it is a very good idea and when (or is that if) I get LNA 607 back on the road again, I fully intend rigging up something on these lines even in the temperate climes of the UK - modern traffic is so slow!!

Paul
Paul Barrow

Seems a bit pointless to fit an over-flow expansion tank to catch the water that escapes from the head-tank of the radiator, when it is the job of that same head-tank to keep a reservior for that very purpose. It holds about 3 pints in reserve in the tank for expansion and to replace water lost through evaporation. What next, another expansion tank to catch the water that escapes from the expansion tank, and another???

Neil.
Neil Cairns

Neil,

You are right. A low water level doesn't mean a shortage: there's just room for expansion.

But I spoke to someone who fitted an expansion tank to his (pressurised) TF, just to keep busy. Now he's reverting to original again; it keeps him of the street!
If it's just to keep busy there's no harm in fitting "modern" extra's, is there? I own the Y for a hobby, for tinkering, polishing and hopefully driving in the future.

Willem
Willem van der Veer

Feel free to come over to tinker with and polish my YB any time you want to!
Steve Simmons

Steve - you pay the air fare and put me up, I'll come, polishing rag and all!

Best wishes

Paul
Paul Barrow

You pay the air fare and I'll put you up, and I'll throw in dinner!
Steve Simmons

Steve,

Thanks for the invitation! My aunt lives in California so maybe you really have to prepare dinner sometime. I might bring my wife, 2 children too. Luckily they all like MG's and your flock of three(?) MG's would reduce withdrawel signs caused by MG-lessness.

(and then I woke up, remembering that buying the Y and being forbidden by my wife to sell the B rendered me pennyless....)

Willem
Willem van der Veer

I should allow travelling MG enthusiasts to come enjoy my collection and charge a therapy fee! Could help pay for maintenance. :)
Steve Simmons

Re. the radiator water level debate, my Y Type has a calorimeter (temperature gauge) fitted in the radiator cap. Unfortunately the calorimeter has only a short sensing tube, so it needs the water level in the rad to be right up to the overflow pipe at all times to give a meaningful reading.

I solved the problem by fitting a small expansion tank based on the 'Aussie' design - it works a treat, the rad. head tank is always full and now I've got some indication of water temperature. (I know these calorimeters aren't desperately accurate but it's better than nothing).

Bill Bennett
Bill Bennett

Jerry Felper at British Automotive fitted a small tube to the bottom of his calorimeter to reach farther down into the radiator. You may want to contact him about it.
Steve Simmons

This thread was discussed between 31/08/2003 and 02/10/2003

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