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 - Water temp. Gauge

The gauge on my 1275 has always run at the normal setting, (gauge reads cold,normal and hot), and I had the electric fan set to come on when the needle just moved past the normal. Lately the needle just sits between cold and normal, and does not increase, but the fan still comes on when you would expect it to, ie in a traffic jam.
I would expect a gauge to fail either not working at all, or go full scale, not just sit between c and n. Is there any way to check out the gauge, before spending £100 on a new one. (its a dual mechanical).

Thanks Dave
Dave Barrow

Maybe your theromstat is becoming u/s so the water in the head doesn't attain high temps (where gauge is measuring)? (It's saying open...)

When gauges fail, they do so as result of losing aclohol through leak in capillary tube; first noticed by smell of alcohol (which is rather nice) and gauge reading lower - so don't rule this out.

But maybe check stat first.
Anthony Cutler

there could be crud build up around the "bulb" that keeps the coolant temperature from getting through

or there could be corrosion inside your gauge that has interfered with the needle travel

or there could be a super slow leak in your capillary tube that let some of the ether out


In any case, you can test it by removing the bulb from the head and dipping it into a pan of some hot water (use a cooking thermometer in the water to compare that temperature with what the gauge reads).


Or, the thermostat could be failing in the open position, preventing the engine from reaching full temperature but allowing it to get warm enough to activate the electric fan still. Test that in another pan of water, and it should open at the temp stamped onto its top (165, 180 or 195, or whatever).


Norm
":oD
Norm Kerr

Anthony
Thanks for the reply, but I forgot to mention that I thought the Thermostat was OK, by feeling the hoses on warm up, also I am mystified as to why the electric fan seems to be working OK.(the sensor is in the top hose).

Dave
Dave Barrow

Thanks Norm, crud around the sensor is a possibility, I will look at.

Dave
Dave Barrow

On my 1275 my previous temp gauge always read between half to two thirds of the way between C and N until I switched the engine off then it would got to N

My present (brand new) gauge shows exactly the same

On both guages, even with a glance the needle can be seen moving up or down sometimes even after the engine has warmed up

Originally I had the engine cooling fan only but for the last 8 months it's been the electric fan only

If I remember correctly the previous gauge I changed because it started showing only just passed C
Nigel Atkins

I would check the temperature with one of those infrared readers. I had suspected that my gauge was reading hot but when I took readings with the meeter, I found that it was reading spot on.

The cooling fan may be coming on prematurely. Mine needed to be readjusted periodically.

Paper ring under the glass on the gauge might also be fouling the needle past N.

Best to know the real head temp before you start spending money
Glenn Mallory

Thanks for all the answers, I will do some checks.

Dave
Dave Barrow

This thread was discussed between 18/06/2010 and 19/06/2010

MG Midget and Sprite Technical index

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