running cold

[steve smith]

todya i noticed that my 1989 2.0 i mg seems to be running a bit cold btu wen u sit in traffic she only gos half way on the temp gauge the fan does cut in but she never seems to warm up unless stood in traffic could there not be a thermostat in her the water pump is ok and the rad warms up all over . any ideas?????

[G Force]

Hi Steve. It does sound like a new thermostat will sort that little problem out. Thermostat sticking open is most likely. :)

[MaestroMatt]

They are designed to fail in the open position - sounds like that's what's happened, as G Force says. Do a forum search on the topic to read advice and warnings about this not-as-simple-as-it-should-be operation! Best of luck...

[Landcrab1800]

Hi,

Read my post Rich Running for some ideas.
I have had the same problem and tried most things. Now I am going to lie to the MEMS.

The reason I lie is that the temp sensor is one of the main fuelling componants. The hotter the engine (temp gauge)the less go juice u use.

[steve smith]

i replaced the thermostat yesterday and it runns a lot warmer than it first did so i think i have solved it but where about is the sensor ???? i may change the whole lot if i can afford it ....

[E_T_V]

After changing the stat and if the temperature sensor doesn't get near to half way then start thinking about other things. Change the simple (cheap) things first before moving onto other options.

[E_T_V]

D'oh posted at the same time!

Glad it seems to have worked. I'm not sure where the sensor is on the O series but it'll be a single blade terminal poking out of a brass nut located on one of the cooling pipes. (on the a series it is just under the thermostat and is usually found in this area on other cars). I think mine was somewhere around a fiver when I changed mine a year or so ago. Your local motorfactor will get you one no problems.

[steve smith]

yeah the gauge goes no where near half way so i thik the senors is knackard will get one tomorrow.

[steve smith]

also the fan comes on early too not even before its reached half way

[E_T_V]

There are two sensors. One to control the fan ( a thermostatic switch on the back of the radiator) and the other to control the ECU and temperature gauge.

My guess is a bad contact or a duff temperature sensor (rather than the thermostatic swich) but both are easy and cheap to change.

Remember to wrap the threads of new temperature sensor in plumbers PTFE tabe before you screw it in so it doesn't leak.

[lamonto]

thanks for info. my 2.0I mg monty is also running rich when cold.
fiddled with the temp sensor and improved matters temporarily.
will now change sensor unit and thermostat. after fiddling with temp sensor connector I suspect a bad or corroded connection.

Ian