I think it is common for hybrids not to have engine/coolant temperature gauges (or tachometer) because the gas motor isn't always on during a drive cycle. Instead, a warning message will come up in the driver display if the engine is overheating. Both the Accord Hybrid and Insight manuals show this is the only indicator (see attachment). And it seems the Accord Hybrid and Prius lack these same indicators. Skimming online, it looks like there are non-OEM/aftermarket options that can use the OBD port reader for this coolant temperature measurement, if desired.