1995 Mercury Marquis no heat

BCBOY

MEMBER
1995 MERCURY MARQUIS
V8
2WD
AUTOMATIC
47,000 MILES

Just inherited this low mileage grand marquis which is in great shape but blows only cold air. Needle on dash guage is in straight up position (way above the H) and only occassionaly will suddenly drop to mid range. Mechanic has flushed the system which he said was muck 3 times and replaced thermostat which produced mild heat but now its back to cold air?

Friday, March 20th, 2009 AT 8:30 AM

3 Replies

RACEFAN966

MECHANIC
5,029 POSTS

Ok first check the coolant level and make sure it is full first. If you need to refill it make sure what color the fluid is as you do not want to mix colors or get the all makes all models formula. If the radiator was that dirty then so what the heater core so I would have the heater core back flushed and if it is mud too then it may need to be replaced. Get back to me with what you find.

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Friday, March 20th, 2009 AT 10:16 AM

BCBOY

MEMBER
2 POSTS

I will suggest to my mechanic but I presume he has done this already. Does this car have a heater control valve? Could that be it? Where would it be located. Under the hood?

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Friday, March 20th, 2009 AT 11:17 AM

RACEFAN966

MECHANIC
5,029 POSTS

In order to answer that I need to know if it auto heating system or manual. In most cases on these no there is no heater control valve it is a blend door and motor in the heater case near the blower motor. Now if the system was that plug as you say though I would still say back flush the heater core and if mud comes out again then I would do a full flush again and replace the heater core.

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Saturday, March 21st, 2009 AT 9:37 AM