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MG Midget and Sprite Technical - Coolant Loss

My car seems to have lost about 1/4 of its coolant with no visible signs of a leak. It had a new radiator and set of hoses in July and they seem to be watertight.

Any suggestions on where/how to find a leak. I suppose it could be a HGF or leaking onto the hot engine block.

Any neat tricks for pressure testing a midget 1500 system?

-- Josh
Josh L

Flush the coolant and heating system thoroughly. Check and tighten every hose and clip meticulously, ensure the header internal pipe is not immersed in sediment, pressure test the header tank (put the cap on and blow down the pipe, replace cap if leaking, and if sure all is well go for a blast.
Over a period of 3 months of repeating the above in varying degrees it eventually worked for me;

Blew the head gasket properly.
Dave Squire (1500)

When I replaced the rad I flushed everything, and replaced the hoses. Everything was clean and free flowing. Think I need to pressure test the system somehow, pondering where and how to attach a bicycle pump.

-- Josh
Josh L

I think that a bolt-in schrader valve, installed into a plastic filler plug would do the trick quite well.
Anyone know what thread the filler is?

Josh L

I've found a pressure test will find a big leak but not always a small leak

check you pressure cap as no visible signs (if correct) means its blowing out the overflow pipe of going through and out of the exhaust

you could also start your engine get it up to temperature and with the pressure cap off look for air bubbles

you could borrow or buy a compression tester

you can buy or borrow some thing like a Frost block test kit if you think it really might be HGF - http://www.frost.co.uk/block-testers.html
also see, this page, ignore title and very top of this web page - http://www.frost.co.uk/how-do-i-flush-and-refill-my-cooling-system you can borrow or buy a

a few possible signs of HGF

missing whilst running
loss of power
coolant in the oil (white mayonnaise but this can also be from short journeys only)
gases in the coolant
can runs hot
lost of coolant

these things are not always all present or noticeable at the beginning at least but are more noticeable later or with hindsight
Nigel Atkins

two reasons I use 4-LIFE (undiluted) coolant are that, main reason - it shows up even small leaks and where they originate and if the leak is from when the car is just hot or hot and cold, second - it turns yellow if you have gases in the coolant system

but it will find weakness in the engine if they are there so best for rebuilt engines
Nigel Atkins

This thread was discussed on 17/04/2013

MG Midget and Sprite Technical index

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