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 Midget and Sprite Technical - Mk 1 midget temperature gauge sender puzzle

I have a Mk1 midget with a 948cc 9CG engine. Attempting to remove the temperature sender unit (Jaeger instrument) I see that the sender is fitted into the cylinder head with a larger diameter adapter (circa 5/8ths inch thread diameter). The sender and adapter are completely seized together so I'm a little stuck at the moment. Looking at Moss spares catalogues the 9CG cylinder head is shown with a blanking plug and washer where the temperature sender normally fits, and I've yet to find where the sender should fit in a 9CG head. I am assuming that Mk 1 midgets had a temperature gauge fitted as standard but what I have on my midget is a bit of a puzzle. Any clarifications would be appreciated. Any other Mk 1 midget owners out there?
many thanks
Ian F.
I Fozzard

I think you'll find that the temperature sender was fitted into the top of the radiator on a Mk1.

You'll probably find a blanking plug there.

The adaptor is used to prevent the bulb of the sender bottoming out in the head.

You will need lots of penetrating fluid and an equal amount of patience if you want to remove it intact. I'm assuming that the gauge works?
Dave O'Neill2

If you have a look at this photo, you can see the blanking plug in my radiator, just below and to the right of the top hose.


Dave O'Neill2

Hi Dave, thanks very much for this reply, very helpful and solves the problem (apart from getting the adapter and bulb apart of course!). The gauge is working fine but I needed to take the bulb out because I'm taking the engine/gearbox out to change the clutch (bad clutch drag making the car undrivable). Because the adapter and bulb are seized it means twisting the capillary as they are unscrewed, but I may be lucky enough to get them back in without breaking anything. Main positive outcome is that everything is as fitted to a midget, albeit a later model, and not some home made lash-up!
thanks again
Ian F.
I Fozzard

as Dave put
>>You will need lots of penetrating fluid and an equal amount of patience if you want to remove it intact. I'm assuming that the gauge works?<<

use a good penertrating/releasing fluid (not WD40) and leave as long as possible, overnight and more if possible, try to remove if it doesn't work soak and leave as long as possible again, repeat as required

I've not had the problem you have (mine wouldn't seal well at first) but I've used a good penertrating/releasing fluid on many things and with patience it's always worked for me
Nigel Atkins

Thanks for these comments - all dismantled now using Plus gas and moderate heat, but the bulb did not survive.The whole lot was corroded into a solid lump and when unscrewed (eventually) the bulb was found to have a minute pin hole which bubbled when placed into hot water - and the gauge stopped working of course. So a recon Jaeger gauge is required. I think I will blank off the cylinder head hole and refit into the radiator as original for a Mk1 midget - any reasons why this might be a bad idea? Presumably MG moved the location for a reason/

Ian F.
I Fozzard

I prefer to measure the temperature of the engine rather than the radiator.

If the thermostat sticks - either open or closed - you won't have a very good indication from the radiator.
Dave O'Neill2

This thread was discussed between 04/05/2012 and 06/05/2012

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.