There is long downhill stretch of highway coming out of some mountains into a valley where I live. When coming down that grade there is usually no need to apply any throttle, just coast down with the car in gear (automatic trans.) When I do this the engine temp gauge goes all they way down. When just driving normally in town or on the highway the temp stays in the normal range. Is this normal or is there a thermostat problem?

Oh, forgot to mention, '94 Accord EX.

 

Could be a stuck open thermostat. When you first start the car (cold) does the coolant flow right away.

 

Hadn't thought to check that, but will do it today. Thanks!

 

Yup, stuck open Thermostat. The T-Stat is also known as a restrictor to keep an engine at it's normal operating temp.

 

Coolant in the radiator does not appear to flow until the engine has warmed up. A couple of minutes after the idle settles to normal the coolant begins to flow.