I have a 2002 Grand Cherokee that over heats only in stop and go traffic.

Asked by May 29, 2017 at 07:19 PM about the 2002 Jeep Grand Cherokee

Question type: Maintenance & Repair

I have a 2002 Grand Cherokee that over heats only in stop and go traffic.
Did extensive testing on the fan relay and motor and it checks okay. When
engine is cold and I turn on the AC the fans comes on and continues to run
while AC is on so I know the fan works. With the AC off and the engine hits
over heating temp the fan is supposed to come on but won't. It continues to
over heat until I turn the engine off to prevent destruction.  Why would the
fan turn on and off with the AC button but it refuses to come on when it
over heats? Also, once it hits the over heat temp the fan won't come on
when the AC is turned on (only when it is running at normal temp). Has a
new thermostat and radiator.

2 Answers

950

There's two things that the fans turns on for. One is the A/C and the other is high engine temperature. These are run by two separate controls. Apparently the temperature sensor on the engine is not calling for the fan to come on when it's hot. And you are wise to not overheat the engine, especially the 4.7 liter engine having aluminum heads and a cast iron block makes them sensitive to temperature extremes. On a related note, the 4.7 liter engine was known to have plastic water pump impellers that deteriorate with age, making the coolant circulate poorly. I hope this helps.

1 people found this helpful.

Electronic fan relay is bad. Common on Grand Cherokees. It's in a really bad spot behind the front bumper cover.

Your Answer

Jeep Grand Cherokee Experts

  • #1
    inuevafreak
    Reputation
    2,230
  • #2
    Tom Demyan
    Reputation
    2,090
  • #3
    thejeepdoctor
    Reputation
    2,010
View All

Related Models For Sale

Used Jeep Cherokee
67 Great Deals out of 8,352 listings starting at $222
Used Dodge Durango
102 Great Deals out of 1,059 listings starting at $3,480
Used Ford Explorer
36 Great Deals out of 1,626 listings starting at $2,900
Used Jeep Wrangler
96 Great Deals out of 2,163 listings starting at $5,495
Used Toyota 4Runner
523 listings starting at $4,995
Used Chevrolet Tahoe
8 Great Deals out of 888 listings starting at $6,800
Used Ford F-150
494 Great Deals out of 10,790 listings starting at $2,995
Used Chevrolet Silverado 1500
172 Great Deals out of 11,772 listings starting at $3,995
Used Chevrolet Camaro
1,119 listings starting at $5,900
Used Ford Mustang
1,164 listings starting at $4,979
Used BMW X5
32 Great Deals out of 997 listings starting at $4,500

Used Cars For Sale

2018 Jeep Grand Cherokee For Sale
20 Great Deals out of 2,594 listings starting at $35,537
2017 Jeep Grand Cherokee For Sale
107 Great Deals out of 674 listings starting at $26,900
2016 Jeep Grand Cherokee For Sale
18 Great Deals out of 220 listings starting at $24,500
2015 Jeep Grand Cherokee For Sale
249 listings starting at $21,990
2014 Jeep Grand Cherokee For Sale
308 listings starting at $18,988

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.