2003 mercury grand marquis overheating, after replacing fan and thermostat

85

Asked by Jun 11, 2015 at 01:20 PM about the 2003 Mercury Grand Marquis LSE

Question type: Maintenance & Repair

My 2003 mercury grand marquis is overheating, even after replacing the fan and
thermostat.  There does not appear to be any problem with the water pump.  I can drive it
all day at hiway speeds, but in stop-and-go traffic, it starts to heat up.  Any ideas?

12 Answers

295

Sounds like radiator sometimes the water pump looks good but may not be tho u need to get a radiator. Tester to see really it will test all

295

Auto zone test that

1 of 1 people found this helpful.
1,235

Are you sure the fan is coming on? maybe the thermostat switch is bad. Bad radiators usually show up at hiways speeds,

1 of 1 people found this helpful.
85

The fan is coming on. It never gets too hot on the hiway, regardless of speed. It only gets hot in stop-and-go traffic, and then not all the time.

4 of 4 people found this helpful.
1,235

Still symptoms of fan not coming on. Did you replace the thermal switch that turns the fan on?. The other thing I would do is pull the radiator and have it checked/flushed. Doesn't cost much, and a good thing to do anyway. How many miles on car? Replace upper and lower radiator hoses at the same time. I've had too many breakdowns due to cooling systems, that I always lean towards overkill. When things are right, these cars run "cool as a cucumber".

1 of 1 people found this helpful.
1,235

This reminded me, once my Grand Marquis was overheating while on vacation with my Wife & dog. I pulled the radiator when I got home and took it in, and it turned out it wasn't plugged inside, but the outside was clogged with dirt so air couldn't get through. One can't tell, because the A/C condenser is in front of the rad. Have that puppy pulled, cleaned, flushed, new hoses and coolant. One is supposed to do this anyway, just as routine maintenance. We all tend to neglect our cooling systems until something goes wrong, and it's always at the worst possible time. I could tell you stores. Too soon oldt, und too late schmart.

1 of 1 people found this helpful.
85

Still having the same problem. I noticed that when I had the thermostat replaced, they used green universal coolant. I'm going to find a shop to pull/clean the radiator and use yellow coolant as specified by Ford. In fact, I may just go on and buy Motorcraft coolant. I've already called two shops that don't use anything other than green, even though one guy admitted it would be best to use yellow.

1,235

I've been using green and my 2002 is cool as a cucumber. How about the thermostat that turns on the fan? My first suspect.(or the relay)

1,235

Did you pull the radiator and have it flushed and checked? That's what I said to do if the fan's coming on in traffic.

85

I'm going to have it cleaned/flushed, and I still may go on and replace the coolant with yellow, even if I have to go to Ford to get it, just for my own peace of mind. The fan and thermostat were replaced together about a year ago. But I have not checked on one thing: Isn't the fan supposed to come on with the a/c regardless of the temperature?

1 of 1 people found this helpful.
1,235

I think you're right, it comes on with the AC, I'll check on mine tonight. See if it's coming on. The radiator guys will tell you if there was a problem with the radiator.

85

Finally found the right mechanic... Did I mention I have an interceptor package? Previous mechanics did not look up parts by the VIN, so I had the wrong thermostat, plugs, and INTAKE MANIFOLD! The 'regular' one is smaller that the interceptor, though it will fit. Also found some jelled coolant in the manifold. It wasn't cheap, but had it all replaced, and it runs like new.

1 of 1 people found this helpful.

Your Answer

Add photo

Related Questions

  • 2003 Mercury Grand Marquis middle vents doesn't blow anything 1 answer

    I have a 2003 Mercury Grand Marquis. My defrost and floor vents work, but the middles vents doesn't blow anything. Also my vehicle gets cold but it seems as if the cold air escapes. I have electric...

    2003 Mercury Grand Marquis LS Premium

    -

    Maintenance & Repair

  • Still Overheating 2 answers

    When we shut the motor off you could hear the fan roar like a bad bearing, haven't had AC for a couple of years...so we replaced the fan assembly, hoses, new water pump & 190 thermostat....still overh...

    2004 Mercury Grand Marquis

    -

    Maintenance & Repair

  • Why wont the radiator fan run on my 2006 Mercury Grand Marquis 6 answers

    I have changed the thermostat and the cylinder temperature sensor and the car still runs hot and the radiator fan does not come on. What should I check next?

    2006 Mercury Grand Marquis LS Ultimate

    -

    Maintenance & Repair

  • Help with 04 grand marquis 2 answers

    Hey my 2004 grand marquis is overheating jus got a new radiator and fan and new coils it still slowly creeps past half temp n starts to overheat n smoke I also got new temp gasket n thermostat.... ...

    2004 Mercury Grand Marquis GS

    -

    Maintenance & Repair

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 1,804 nationwide Grand Marquis listings starting at $2,250.

ZIP:

Search Mercury Grand Marquis Questions

Mercury Grand Marquis Experts

#1 Tracy Hooks
Tracy Hooks
Reputation 5,460
#2 kbro
kbro
Reputation 2,060
#3 Js08016
Js08016
Reputation 1,770
View All

Related Models For Sale

Used Ford Crown Victoria
12 Great Deals out of 1,069 listings starting at $2,995
Used Lincoln Town Car
33 Great Deals out of 1,820 listings starting at $1,750
Used Chevrolet Impala
521 Great Deals out of 31,726 listings starting at $1,450
Used Mercury Marauder
25 listings starting at $7,300
Used Ford Mustang
472 Great Deals out of 45,735 listings starting at $1,999
Used Ford Taurus
246 Great Deals out of 20,434 listings starting at $699
Used Ford F-150
2,195 Great Deals out of 206,316 listings starting at $1,499
Used Chevrolet Tahoe
549 Great Deals out of 29,234 listings starting at $1,699
Used Cadillac DeVille
7 Great Deals out of 1,640 listings starting at $1,999
Used Chevrolet Silverado 1500
1,716 Great Deals out of 175,751 listings starting at $1,250
Used Chevrolet Camaro
226 Great Deals out of 30,943 listings starting at $1,217

Used Cars For Sale

2011 Mercury Grand Marquis For Sale
35 listings starting at $4,995
2010 Mercury Grand Marquis For Sale
5 Great Deals out of 90 listings starting at $2,799
2009 Mercury Grand Marquis For Sale
8 Great Deals out of 94 listings starting at $3,790
2008 Mercury Grand Marquis For Sale
11 Great Deals out of 144 listings starting at $2,250
2007 Mercury Grand Marquis For Sale
3 Great Deals out of 140 listings starting at $2,495

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.