Temp Gage in red

My gage is in the red once I start driving car, a 94 355; i took to my mechanic and he says it's one of the two water pumps in the car and thermostat. The car has a whining sound once temp gage is in red. He needs to pull engine to get at water pumps which seems obscure. Also, if whining sound came from water pump, why would i only hear the whining sound only when engine was hot according to the temp gage. Any ideas? Help.

Are you saying your water temperature guage indicates hot as soon as you start the car (which is absurd)? or that the car always gets hot enough after a short drive to indicate an excessive temperature? What kinds of temperatures are you seeing on the guage?

There is only 1 water pump, 1 thermostat, but 2 radiators.

The water pump should be rebuilt or a new one installed at each major service. It is located in a very hard to reach place, and is a minor additional cost when performing a major service, and a major cost when done all by itself.

Whining generally indicates a bearing. Could be the water pump bearing, the power steering pump bearing, or the cam belt tension bearings. When bearing start to go bad, the make a whining sound for a few seconds and then quite down. By the time they are whining constantly, you are in eminent danger of the bearing locking up and leaving you stranded.

If you are close to or over the 5 years service life on the cam belts, This water pump 'dealy' should cause you to consider a whole major service.

the temp gage goes to red after 10 minutes of driving; not immediately on engine start.

then the whining noise starts and continues even when engine shutdown; though not for much longer after engine shutdown