Hi everyone.
just after some help.

I have a 2002 Diamante 3.5 V6.

it has an issue where the water temp gauge will rise to about 3/4 high instead of the usual halfway.

I have seen it occasionally rise further (first photo) but then it drops down again to around 3/4 and stays there (second photo). It never overheats completely and there is no steam or funny noises or smells.

I have changed the thermostat, coolant temp sensor, radiator cap. the previous owner did the cambelt and headgaskets.

the radiator fans appear to be working at the right time. And the radiator seems to be operating normal. The top hose gets hot and bottom one gets warm.

Does this sound like a gauge issue, water pump (I would hope that the previous owner changed it), radiator, or I also read somewhere that the ATF can cause this and needs to be flushed?

Keen to know if anyone else has had an issue with the temp getting very warm but not completely overheating.



Cheers