Mechanics

CAR HEATER

1998 Mercury Mystique • 4 cylinder FWD Automatic • 145,000 miles

Car heat takes a while to start working but doesnt blow heat full blast. Could it be because my thermostat doesn't work or is it something else?
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Ladymilks
November 30, 2010.




When you say "Full Blast", does the blower spin on high? Do you mean the temp doesn't get hot?

As for your thermostat, if it's stuck closed, you'd quickly overheat. If it's stuck open, it would take a very long time for the engine to reach normal temps.

Also, check the heater control valve at the firewall. If all of these things are good, then you'll have to remove the HVAC unit for inspection. You may have a stuck blend door or leaking vacuum hose/solenoid.

Ernest Clark
Nov 30, 2010.
1st check if engine taking long time to reach operating temp
and if so suspect bad thermostat

BMRFIXIT
Nov 30, 2010.
The temp does get hot it just barely blows out any air. And the thermostat just doesn't tell the temp of the car it just says its cold all the time.
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Tiny
Ladymilks
Nov 30, 2010.
Thermostats don't tell temp. But if the temp gauge registers cold all the time, the gauge or sensor may be bad. Your thermostat would have to be stuck in the open position to keep the engine from getting hot at a normal rate, but it would eventually get hot.

It sounds like your blower motor is shot, or the resistor pack may be faulty. You'll need to remove the HVAC unit and check these components.

Ernest Clark
Nov 30, 2010.
Operating temp is about 185 to 195
and the gauge should be at about mid to half way
if not suspect and replace the thermostat

BMRFIXIT
Nov 30, 2010.
If the vent temp does get hot, but your system barely blows air (as you've already stated), then there's something wrong with the Blower motor or resistor pack or control unit itself.

Ernest Clark
Nov 30, 2010.
Okay. Thank You guys so much! I don't think I'm capable of doing any of that to be quite honest but around how much will the repair costs be because I know many mechanics try to overcharge females since we rarely know anything about cars?

Tiny
Ladymilks
Nov 30, 2010.
An honest tech will charge you about 300 bucks to put in a new blower motor if that's the problem. If it's the resistor pack, maybe 200 but you need to make sure you get a tech that knows how to check this. All too often, they misdiagnose this or don't bother checking it at all and go straight for the blower motor.

If you thermostat is faulty, they'll charge you around 100 bucks.

Ernest Clark
Nov 30, 2010.

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