2003 mercury grand marquis overheating, after replacing fan and thermostat

115

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

365

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

365

Auto zone test that

1 of 1 people found this helpful.
1,465

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.
115

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.

6 of 6 people found this helpful.
1,465

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.
1,465

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.
115

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 of 1 people found this helpful.
1,465

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)

1,465

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.

115

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.
1,465

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.

115

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

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 1,698 nationwide Grand Marquis listings starting at $1,995.

ZIP:

Mercury Grand Marquis Experts

  • #1
    Tracy Hooks
    Reputation
    5,830
  • #2
    kbro
    Reputation
    2,150
  • #3
    Js08016
    Reputation
    1,910
View All

Related Models For Sale

Used Lincoln Town Car
30 Great Deals out of 1,723 listings starting at $1,004
Used Ford Crown Victoria
6 Great Deals out of 903 listings starting at $1,496
Used Chevrolet Impala
563 Great Deals out of 36,766 listings starting at $990
Used Chevrolet Tahoe
857 Great Deals out of 44,892 listings starting at $1,980
Used Ford Mustang
607 Great Deals out of 39,015 listings starting at $1,500
Used Ford F-150
3,205 Great Deals out of 239,472 listings starting at $1,300
Used Chevrolet Camaro
500 Great Deals out of 33,566 listings starting at $1,450
Used Honda Accord
1,199 Great Deals out of 74,737 listings starting at $561
Used Ford Taurus
218 Great Deals out of 15,232 listings starting at $1,850
Used Mercedes-Benz S-Class
166 Great Deals out of 8,047 listings starting at $2,000

Used Cars For Sale

2011 Mercury Grand Marquis For Sale
25 listings starting at $5,450
2010 Mercury Grand Marquis For Sale
4 Great Deals out of 91 listings starting at $3,995
2009 Mercury Grand Marquis For Sale
79 listings starting at $2,995
2008 Mercury Grand Marquis For Sale
5 Great Deals out of 135 listings starting at $2,495
2007 Mercury Grand Marquis For Sale
7 Great Deals out of 143 listings starting at $1,995

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.