where is the temp. sensor?

[winstonmei]

1998 Sable station wagon.

The heater is not blowing enough heat and it is identified due to the weak water pump.

I now just have the water pump replaced and I am expect a lot heat. To my surprise, it is blowing cool air ( the outdoor temperature is about 80 F degree (27 C degree)! It look like the air conditioner is now kept on even I turned the manual temp control to the red hot zone (clockwise most)!

Where is the temperature sensor located? ( not the thermsat which is working normal). I want to know if this is due to faulty temp sensor or the mechanic screwed out something when serving the car.

Winston

[pcv]

Replace the thermostat first. That is what controls your coolant temperature. After you replace it, make sure there is no air in the system.

[winstonmei]

The thermostat seems fine. The temp gauge hits 2/5 of range after driving for 15 min. -- just likes usual.

The air it is blowing is colder than ambient temperature and feels from the AC

[Dan_in_WA]

Disclaimer: Most of my knowledge is based on my '87 Taurus wagon. Haven't delved too deeply into my '96 Taurus yet.


But it sounds to me like the blend door between Hot air and Outside air is stuck towards the Outside position.

Cooling system wise, it sounds like everything is probably ok with the exception of (maybe) no water flow through the heater core. When the car is at operating temperature, pop the hood and check the heater hoses, where they go back into the firewall. You shouldn't be able to grab on to them, as they should be HOT!! So be careful.......

Oh yeah, and I'm assuming that the cooling system is completely full of coolant - no air needs to be burped out of the system. How is the coolant level in the reservoir tank doing? Your mechanic most likely purged the system of air after the water pump change, BUT.... there are those few. Something to check.

Lastly, there may be a loose/cracked/broken/whatever vaccum line under the dash. These are particularly evil to trace and fix; but here's where to start:

When you turn the Vent Control around to other positions, does air come out the Floor vents when the control is on "Floor"? Does "Panel" make air come out the panel vents, and so forth?

If so, there is vaccum getting at least to the Vent Control switch and most of the vaccum diaphragms.

If air will only blow out the defroster vents, no matter what the position of the Vent Control, look in the engine compartment, back towards the firewall, for a disconnected vaccum line. (This is the supply line to the HVAC system, and was probably disconnected when the water pump was replaced. On my '87, it's the little plastic line that comes out from between the hose connections for the heater core. Make sure it's connected to the intake manifold.)

Let me know what you find, and I can continue from there, if you like.