whining from 90 honda accord

[br0lite]

My 1990 Honda Accord will make a whining sound that seems to come from under the dash, but maybe on the engine side of the firewall.
It only does it when I am driving about 35 miles an hour. If I apply the brakes the pitch will change higher. If I come to a stop
the noise will stop. Then it wont come back for a day. Also, the car takes longer to supply warm air for the driver. Maybe the sound
is the heater having trouble. Has anyone dealt with this?

 

[CaptainKrunch]

Quick vote here based only on information provided....thermostat needs
replacing, coolant level low, brake pads/rotor squealing. Check coolant,
replace thermostat if fluid isn't getting hot and inspect, remove, clean and
lubricate brake hardware.

CaptainKrunch

My 1990 Honda Accord will make a whining sound that seems to come from

under the dash, but maybe on the engine side of the firewall.

It only does it when I am driving about 35 miles an hour. If I apply the

brakes the pitch will change higher. If I come to a stop

the noise will stop. Then it wont come back for a day. Also, the car takes

longer to supply warm air for the driver. Maybe the sound