No heat/defrost until cruising at high speeds of 55mph or higher.

DONNMAN

MEMBER
1998 CHRYSLER CONCORDE
135,000 MILES

Bought this car used for my son. It will not give heat / defrost for typical city driving. However, when we cruise on highway at 55 or higher the defrost/heat will work. Soon as we slow down though it begins blowing cold air again.

Would this be a thermostat problem? If so, how do we change it on the 1998 Concorde with the 2.7 V6 engine?

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Have you checked the coolant level? It sounds low.

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Sunday, October 16th, 2011 AT 6:07 PM

WRENCHTECH

MECHANIC
20,761 POSTS

That sounds like a restricted heater core. You can try backflushing it with water pressure from a garden hose but it will likely ultimately need a new heater core. Get the rest of the engine flushed thoroughly before installing a new core though.

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Sunday, October 16th, 2011 AT 6:32 PM

DONNMAN

MEMBER
3 POSTS

Thank you for your response's. Yes, we checked the coolant level and it was very low. Topped it off but still blowing cold air at low speeds.

Will have to have it checked for the heater core I guess. Im not very handy with cars and was hoping for an easy fix. Was crossing fingers that topping off coolant would do the trick.

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Monday, October 17th, 2011 AT 12:18 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

I need you to check something. Start the engine and turn the heater on high. Let the engine warm up and feel both heater core hoses. Both should be hot. Let me know if that is the case.

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Monday, October 17th, 2011 AT 2:31 AM

DONNMAN

MEMBER
3 POSTS

We have found leaks in what is a metal tube that runs from the thermostat housing up to the top of the motor. It then has spouts going off to the reservoir and the heater hose. This tube is metal and is about 3 1/2 feet with bends. It connects to the thermostat housing with a rubber piece.

I have called a few places and described this tube and some think it may be a water outlet tube, a coolent tube, or a heater tube.

Any idea on what this part is?