Water temp gauge inaccurate

[emmotto]

1969 Series IIa 88

Water temp gauge works - but seems to have much reduced range of movement (scale).

So when truck is cold it's dead on the bottom of the scale, but as truck warms up the needle never reads higher than upper middle of the 'C' for cold. The needle DOES move but never above 'C'.

I've replaced thermostat with 82c (179f) one, installed RN radiator muff, and verified that I do indeed get HEAT (I know - I should stop lying, right?) out of the standard heater.

I'm pretty sure that the engine is getting to a normal temp but I haven't put a thermometer in the radiator - suppose I should do that..

I've replaced the voltage stabilizer (was oscillating from +14 to +9 volts about once a second) with a solid state one that puts out a steady +10v - this fixed my gas gauge (sometimes) but not the water temp.

I'm in SW CT so it's not like it's all that cold out...

My questions are:
is it possible to have the wrong sender?
Or could some other odd gauge ailment cause it to read incorrectly?
is it more likely to be the gauge or the sender?
or something else?

Mike

[Les Parker]

I would suggest using an infa red thermometer and seeing if you have hot/cold spots.

If the top of the radiator, for instance, is significantly higer/lower than the bottom part, the reason probably is a bad water pump.

Try 6 0r 7 different areas of the engine/radiator and keep notes and advise the BBS how it all shows, temp. wise.