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MG Midget and Sprite Technical - 1500 Radiator overflow tank

I now have her running after 2 years, she fired on the 5th turn of the crank, absolutely amazing, all I have to do now is tune.
However I am concerned about this tank (plastic late model), just realising that it doesn't seem to have any way to bleed except thru the cap. Also I'm not sure I got all the air out of her, had to top up twice after sitting overnight.BTW there are no leaks.
Has anybody had to modify theirs? or had problems?
Rod
R W Bowers

Burp it.

Squeeze the main rad hose.

C L Carter

FYI, if the plastic expansion tank is intended to work as the earlier metal ones do, it should be filled only halfway with coolant, allowing some air space for expansion.

Also, the last time I changed out my coolant, when I refilled it I disconnected the top heater hose from the heater unit, as it seems to be the highest point in the cooling system that can be opened. I added coolant to the rad until it overflowed out that hose, and then reconnected it. Then I filled the expansion tank halfway, and I haven't had any trouble since.

But yeah, CL's advice is good too. Squeezing the hose works.

Hope this helps,

-:G:-
Gryf Ketcherside

I've always just followed the instructions in the Driver's Handbook and never had any problems

you could also run the car with the pressure cap off and what until all the bubbles stop then top up as required when the car is fully cold, Gryf has put you only need to fill to about half way, it will then find its own level for when it's hot and blow out the excess, no point topping up further than this level unless the engine gets overheated and throws out beyond this level

until you drive your car regularly you wont really know what fluid levels it likes and where the guages like to sit and those are not always as the books show
Nigel Atkins

Rod,

When filling the system, disconnect the hose that joins the expansion tank to the top of the radiator at the expansion tank end. Hold it well above the level of the top of the radiator until the water runs out free of air. That is the highest point in the system. Refit it to the expansion tank and top up the tank to the correct level.

I read about it somewhere and it worked for me.

Dave
D MATTHEWS

Thanks gentlemen, it has actually stabilised now and no more drop in level. Yes I agree about half full should do it.
Cheers
Rod
R W Bowers

Help chaps,

Having cleaned my expansion tank on my 1500 and removed decades of crud, it looks as if the long tube inside the tank that connects to the small bore inlet/outlet has a valve in it or is simply blocked with more debris (hard to see through the almost opaque plastic). Can anyone tell me if there is a valve and/or if it's crucial? I need to know before clearing the blockage with stout wire and (possibly) damaging the valve if there is one.

cheers,
Nick
Nick Nakorn

AFAIK it is just a tube
Dave O'Neill 2

Thanks Dave :-)
Nick Nakorn

No valve in there Nick. Mine just flows when flushing off the car. Works fine when on the car. Spare one the same.
Dave Squire

Thanks Dave :-)
Nick Nakorn

on refill of coolant don't forget to follow the instructions in the Driver's Handbook to avoid getting airlocks - it's as Dave Mathews has put a few posts back
Nigel Atkins

This thread was discussed between 04/10/2012 and 21/06/2014

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