MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

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 TD TF 1500 - Variable Temperature

I was wondering if anyone agrees with me deduction?
My temperature gauge shows around 70f most of the time but if I climb a long steep hill, like today going up onto Dartmoor with my wife, the temperature went right up to 90f (the maximum the gauge goes to) until I got to the top then it drops back to around 70f again.
I think it might be because the thermostat is jammed slightly open, meaning the engine never reaches operating temperature on the level and goes to high when under load for any length of time because it doesn't open far enough.
What do you think, am I on the right lines?
The car is pictured with the bonnet sides open to help bring the temperature back down.

CJ Harvey

Good day Mr. Harvey:

My TC6768 uses the same temperature gauge as my TD3191
and both show 100°F as the maximum reading on the dial faces.

Both instruments will hover about 70°F on normal runs but will increase with the outside warmer Summer temperatures.

Conversely; it will be a little slower in attaining the average 70°F mark in the cooler months.

I reckon the thermostat may be the villain as you infer.

I cannot think the engine would run any hotter on a long hill unless the weather was a factor or there was an absence of an adequate water supply within the radiator.

However; my expertise, in things M.G., is sadly lacking.

Cheers then:
Jack Emdall, Halfmoon Bay, British Columbia, Canada
Jack Emdall

CJ - Are you sure that your temp gauge is calibrated in °F and not in °C? Most of the temp gauges used in the T series cars read °C. 70°F is not even body temperature for a human, much less a vehicle engine - even 90°F is not body temp for a human. On the other hand 70°C is about the proper operating temp for a car engine (albeit a bit low) and 90°C is more in keeping with engine temp after a hard climb. The two temperatures you quote, if measured in °C is pretty much what to expect for engine temperatures and nothing to worry about. Cheers - Dave
David DuBois

Good day all:

There I go, with this ruddy Metrification crap.

Yes ! The writing I previously submitted should read in °C throughout. I should have remembered that !

I'd like to have a serious talk with the guy who wrote about the joys of the "Golden Years" !

Sorry for the cock-up; respectfully:

Jack Emdall


Jack Emdall

Ha, yes you're right David, I meant °C, so not to much to worry about then, I think the air temp rose to 23C today, most pleasant :-)
CJ Harvey

It's logical that the engine gets hotter as more power is asked from it climbing a hill.

Apart from your logical explanation, my first thought was a poorly functioning radiator. When was it last cleaned or replaced?
Willem van der Veer

My TD always runs hotter going up steep hills. It's normal.
Ed
efh Haskell

I have the same phenomenon - rapidly rising temperature when I go up a long hill. Quite alarming until you get used to the fact that the car cools right down again when you get on the flat.

Cheers
Dave

1955 MG TF
D Moore

I sweat more (temp rise) and my legs burn when I pedal my bike up a hill (load) and I cool down when I go down the hill - (no load)
Frank Cronin

I have an electric temp sender fitted just below the thermostat in both my Y's (YA & YT), and what you describe is quite the normal temp range you will see if the sender is in the top tank of the radiator.

The ideal water temp leaving the head should be around 80-82deg C, but it will rise to near 95 if you push hard up long hills.

Remember that the thermostat is the hardest working component in your cooling system - it is constantly adjusting it's opening to try and maintain the temp at 80 degrees. It can only react to the heat generated, it can't read the road ahead, so there is always a case the temp will rise under hard work.

Removing the thermostat is no way to cure the heat build up either - the water will flow too quickly through the radiator & not dissipate the heat and the temperature will steadily rise without hard work.

The cooling system in an XPAG only gets rid of around 11% of the heat generated, so it can only do so much !.

Just my 2c worth

Tony
A L SLATTERY

My temperature gauge is a good grade indicator for the steepness of the road. This is also true for some other old cars I have. They have no cooling margin for extra load going uphill. Mike
MW Davis

The only effect I have seen with removal of thermostat is the engine takes longer to reach operating temperature and will run too cool. Others may have a different experience. Regards, Tom
tm peterson

Controlling/maintaining temperature is the job of the radiator & its "brain", the thermostat. Removal of the thermostat was discussed at an MG Restorers Association TD Tech Day here early last year. What follows is a summary.

In the past many PO's had reasoned that running without a thermostat was a good solution to overheating. Not so. The problems with running a car without a thermostat are that the radiator is effectively bypassed as much of the water/coolant takes the path of least resistance, the shorter bypass route back through the engine, again & again. Eventually the water/coolant in the system reaches the same temperature but the radiator doesn't get to treat the coolant when it needs it most, just after it has left the engine. This reduces the efficiency of the cooling system. It also takes much longer to get the car up to temperature on startup. This is not good as engine wear is greatest when cold. Cars that have deleted the thermostat also show more noticeable wear in cylinder No 1 as this runs comparatively cooler than 2, 3 & 4. Neil Cairns wrote a good article on overheating in Safety Fast a while back which explains the clever interaction of the thermostat & its bypass sleeve & is well worth reading. Cheers
Peter TD 5801
P Hehir

This thread was discussed between 17/05/2014 and 22/05/2014

MG TD TF 1500 index

This thread is from the archives. Join this live forum now