Really odd E46 320d temp guage issue

[Brian28]

My car doesn't overheat, but I have an issue with the temp guage on long journeys. Sits bang in the middle for about two hours, then starts to creep up. When switched off, the guage only drops back "half a guage" to rest. ie if it has gone up to register 3/4, when switched off the needle only goes back to 1/4 not right back to the left. I use live temp reading on the OBC, the water temp sits a few degrees either side of 80, the car definitely isn't running any hotter when the guage rises. And it only happens after about two hours constant driving, any less and it sits bang in the middle. Driving steady or harder, back roads or motorway makes no difference, always happens about two hours into a drive. When left a while (hours, not minutes) the resting position moves back to where it should be. Anybody ever come across anything similar?

[bss325i]

Sounds like something is getting hot inside the KOMBI (instrument cluster) over that period of time causing the gauge to behave erratic.

As you say, you've checked the temp using the OBC and its fine so its prob going to need a replacement cluster.

[Brian28]

Helpful thanks. If it isn't a common problem worth having a fifty quid punt on a set of used clocks, or just bite the bullet at main dealer new part?

[bss325i]

If you can borrow an instrument cluster for testing purposes then do it. Its not a common fault.

[Brian28]