Engine overheated the temperature went to 221 degrees?

Tiny
BENEFITS1976
  • MEMBER
  • 2002 JEEP GRAND CHEROKEE
  • 4.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 192,000 MILES
Today I took a small hill the temperature went to 221degrees. The vehicle listed above has a hydraulic fan. What I did so far. I unplugged the coolant temperature sensor. The fan went in its maximum speed in two stages.
Saturday, October 12th, 2024 AT 2:56 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,602 POSTS
When the Jeep was overheating could you hear the radiator cooling fan kick on? If not, I would replace the engine coolant sensor. Here are the instructions how and a guide to help you go over the additional reasons it can be overheating.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Check out the images (below). Please let us know what happens.

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Sunday, October 13th, 2024 AT 10:09 AM
Tiny
BENEFITS1976
  • MEMBER
  • 27 POSTS
The fan runs all the time. When the car overheated, I did not hear the fan speed up. However, when I start the car and let it idle, the car will not overheat. The maximum I saw was 210 at idle.

The fan is hydraulic. It uses power steering fluid and is controlled by the computer by increasing pulse cycle to the solenoid.

Can you send me a wiring diagram of the engine cooling system?
Also, what is the jeep operating temperature?
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Sunday, October 13th, 2024 AT 10:52 AM
Tiny
KEN L
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  • 47,602 POSTS
Normal operating temperature for the engine should range between 195°F to 220°F (90°C to 105°C). Here is the wiring diagram for the cooling fan. Check out the images (below). Let us know how it goes.
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Sunday, October 13th, 2024 AT 5:42 PM
Tiny
BENEFITS1976
  • MEMBER
  • 27 POSTS
Hi,

When I disconnected the connector from the fan I saw ground on pin 1 also in fuse 16 with engine off ignition key out. Also, I saw ground on pin 3 and nothing on pin 2.

I thought I was supposed to see nothing (no ground no power) on pin 1 and fuse 16 until the ASD is energized. Right?

Also is it safe to use a test light to check if the computer is controlling the fan on pin 2 while the engine is running.
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Monday, October 14th, 2024 AT 11:41 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,602 POSTS
With the key on you should have power at pin #1, for pin #2 just check the continuity to the PCM. Let me know how it goes.
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Tuesday, October 15th, 2024 AT 8:57 AM

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