Temperature Gauge-Help!

The temperature gauge on my '98 ZX2 reads halfway even when the engine has been off for days. When the engine is run, the gauge goes up to nearly the overheat range. The gauge never goes down to "C" when the engine is shut off. Could this be a misread due to a stuck needle, or should I start looking at the cooling system? (FYI coolant level is in the normal range).

I had the same problem with my 98 Zx2. Turned out to be a cracked main body of the radiator itself. Had a new one installed (and the thermostat at the same time) and the gauge no longer shot up. The new radiator does however allow the needle to run a little higher up than the OEM radiator did, but still runs norma and does not overheat. Hope this helps.