Question about 1998 Mercury Mystique

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Heater core replacement for a 1998 Mercury Mystique

When I turn on the blower for my defroster and heat in my car its just blowing out cold air

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Change thermostat

Posted on Jan 15, 2013


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Posted on Jan 02, 2017

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SOURCE: 2002 Mercury Sable, Heating Problem

Hello. You are in luck. I just had this same issue in my shop this week. We changed the thermostat, and replaced the coolant. Fixed it right up. Since you did not mention a new thermostat, that would be my next move, if I were you.

Posted on Oct 09, 2009

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SOURCE: 2002 mercury sable heater wont get hot

you have a broken or stuck temp blend door in the heater case. or the servo motor is broken. this sits on top of the heater case

Posted on Dec 02, 2008

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SOURCE: heater doesn't work

This happens ALL THE TIME!! Heater core is likely plugged with rust, yes. but a garden hose fix will NOT last. and the reserve probably IS cracked on bottom, as most are.They are relatively cheap from Ford, though. Have a REPUTABLE radiator shop do a Genuine Power Flush to the entire cooling system (not an automated fluid exchange many shops claim to be a "flush") and THEN have them unplug the heater in a similar fasion. Now is the time to replace the surge tank (old one is packed with rusty sediment that is usually partially plugging the cracks in it, and not very cost effective to clean anyway). On older, very rusty 2 valve 3.0 systems only other issues are the rear of timing cover gasket often leaks a little, and the water pump impellers can become eroded away (from rust) and water flow suffers. So... watch for residue or dripping from behind water pump. If minimal, a mild leak sealant added to a properly cleaned system with refill and tightening the bolts near leak will do the trick--otherwise timing cover gasket and pump replacement is needed.

Posted on Jan 01, 2009

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SOURCE: The heater in our car is not blowing hot air. It

Check the heater hoses under the hood first to see if they are hot. if they are, there is a temperature control actuator on the top of the heater box. the motors go bad, and the temp door does not move. The motor is hard to get to but if you open the glove box it is to the left, almost behind the radio.

Posted on Oct 16, 2009

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SOURCE: 2003 mercury grand marquis LS

The blend door is stuck in cold position. That usually happens because the blend door actuator has failed.

You will need to test and replace the blend door actuator.

To replace the actuator you will need to take apart the dash and remove completely the instrument panel,d isconnect the connector, remove the four screws, remove the temperature blend door actuator and replace it.

The replacement is not a job for beginners, since you have to take apart the dash to access the actuator.


Posted on Nov 18, 2009

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1 Answer

Heater Core replacement

first, check the coolant level and add if its low..check for accidental ac turn-on at the controlls..then its an issue with the controls themselves provided the water pump is good..there are baffle doors that are controlled reemotely in the dash and one of these couldd be not functioning or blocked by debris like a penny sliding into the defrost vent will jam the door and keep it from working...check these and see...good luck..

Jan 15, 2013 | 1998 Mercury Mystique

1 Answer

The heater and a/c quit working on my 1998 Mercury Mystique.

Could be a fuse/relay in the electrical box under the hood. Take the lid off and flip it over. You should see a diagram of what relay control's what. If not it will be in the owners manual or search it up on could be the fan/blower motor went bad or just the resistor for the fan/blower motor.

May 13, 2017 | 1998 Mercury Mystique

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I replaced the thermostat, but it still blows cold air. What gives?

The ford taurus and mercury sable are very well know to have coolant pressure, heat problems. I have worked on a minimum of 300 of these specific vehicles in my career, I can tell you the system is a headache,yet manageable. Are you getting cold air through the vents? is the blower motor working? Is your antifreeze brown in color or goo like? (a tell tale sign of a broken water pump and 90% probability of a clogged heater core.
also other basics, have you flushed the system and checked to make sure the car is not air bound?

Feb 18, 2011 | 1998 Mercury Sable

1 Answer

The heater is blowing cold air

heater control valve not allowing radiator water to flow through the heater core where the heater blower motor blows the heat that radiates off the heater core into the vehicle cheap fix or you can bypass yourself by replacing valve with piece of 3/4 copper pipe and 2 hose clamps

Jan 03, 2011 | 1998 Dodge Caravan

1 Answer

98 bonneville , blower only blows cold air , replaced control head and thermostat, heater core is good , there is hot air at the blower motor

This is usually caused by a control door inside the housing for the heater. Sometimes pens or other obstacles go down the defroster vents and block the doors. Lay on the floorboard while someone controls the heat and vent controls. You should be able to see the arms controlling the vents and heat. You may have to remove the lower dash covers to gain access to see these controls. Also check to see if there are any engine vacuum leaks. The heater and vent controls are ran by vacuum sometimes.

Dec 29, 2010 | 1998 Pontiac Bonneville

1 Answer

My fan for my heat and air in my 99 mercury mystique is working but I have no heat. I believe it might be that the heater core is clogged, but I can't find its location. I can't afford to replace the core,...

There is a switch on the control console that activates the heater door control. The door control is located behind the glove box. (You have to remove the glove box to get to it) If the switch on the console is bad, or the door control is bad, the door may not be opening to allow the blower to blow through the heater core and into the cab. I would think that if the core were plugged or coolant wasn't allowed through it, it would cause the car to overheat. its called a blend door it turns different ways door can stick causeing no heat

Dec 09, 2010 | 1999 Mercury Mystique

1 Answer

I have a 1998 Honda civic 1.4i.Turned car on this morning heater on full to defrost windscreen.After 10 minutes still blowing cold air!No noises etc and all settings work but still cold air.Help!

Are the radiator hoses from the engine to the firewall hot? If so, it's probably not the thermostat, it's probably either the heater core or the controls not allowing the heat to get in. Best advice I have (because I had to replace the heater core in my car last year) is to buy a Chilton repair manual for it. it walks you through everything. If it is a heater core, be prepared for a long job...

Nov 28, 2010 | 1998 Honda Civic

2 Answers

Antifreeze steam comeing through vents

Your heater core has a leak, it's like a small radiator that heats up and the blower motor blows air thru it to create heat in the car. It is leaking anti freeze into the heater box.

May 12, 2010 | 1998 Mercury Sable

2 Answers

1998 for taurus heater wont blow hot air only cold .was driving down the road I TURNED THE HEATER OFF FOR A COUPLE MINUTES WHEN I TURNED IT BACK ON IT WOULD ONLY BLOW COLD AIR.IT IS ELECTRONIC SWITCH'S.THE...

you need to check the blend door in the heater box it maybe broken or stuck.the blend door switches between the heater core and ac evaporator to provide a mix of temperature

Oct 18, 2009 | 1998 Ford Taurus

1 Answer

Just got heater core replaced and now have no heat from heater or defrost. Fans work, just don't blow anything beyond "cool". The heat in my car is coming and going. I want to know how to fix...

It sounds like when they replaced your heater core, that they didn't properly hook up the blend door contros at the control panel. I would take it back to the repair shop that did the work and have them go back over things again just to make sure.

Dec 04, 2008 | 1992 Mercury Cougar

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