Nissan Repair: 97 200sx heater not working right, coolant temperature sensor, heater control valve

Question
I have a '97 Nissan 200SX SE, a/t, 140k.

The heater doesn't seem to work right. On a cold morning (<50 degrees), I'll go out start the car & turn on the heat. Come back 10 minutes later and the car is warmed up to normal (or close to it). But the heater won't be blowing hot; it'll be warmer than outside air, but not hot. But, by the time I get to the end of my driveway (100 yards) it'll be blowing hot.

I've replaced the thermostat & coolant and done a flush. I've also tried pulling the wire off the coolant temperature sensor and the radiator fan will immediately kick on. (Does that mean the sensor is ok?)

Any help or suggestions appreciated.

-Wes

Answer
Hi Wes -

First thing I would check is your heater control valve. If you follow the heater hose from the firewall, you should run into it. I believe your year it is run by vacuum, So first check the vacuum line by starting the car and pulling the vacuum line off the valve. If you feel vacuum through the hose, then replace the valve. If there is no vacuum, then check the hose for breaks, and the source for blockage.


Hope thie helps -
aloha
calvin