Temperature gauge says overheating all the way to hot

262,000 MILES • 2.3L • 4 CYL • 2WD • AUTOMATIC
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DANIEL FLEISHER
  • MEMBER
  • 1 POST
I have changed the thermostat a week ago. i changed the coolant temperature sending unit with the single wire. today car still says it is overheating. the top hose is hot the bottom hose is warm. i don't know what to do other than buying coolant temperature sensor that is in thermostat housing. someone please help.
May 27, 2019 at 7:12 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,244 POSTS
Welcome to 2CarPros.

When the gauge says it's overheating, does it seem as though it is actually happening or does it seem the gauge is incorrect? Also, does it happen all the time regardless of speed or more so in stop and go traffic? Also, have you tried flushing the radiator?

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

First, I attached a picture of the sensor to confirm it is what was replaced. See picture 1

If it was, then we need to check the sensor itself. Here are directions explaining how to check the sensor. Pictures 2 and 3 correlate with the directions.

COMPONENT TESTS AND GENERAL DIAGNOSTICS

pic 2


1. Disconnect the YEL/GRN wire (A) from the coolant temperature gauge sending unit (B).


pic 3


2. Using an ohmmeter, measure the change in resistance between the positive terminal (C) and the engine (ground) with the engine cold and with the engine at operating temperature.
3. If the obtained readings are substantially different from the specifications above, replace the sending unit.

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Here are a few links you may or may not find helpful when testing (you may already know how to use them and perform these types of tests):

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

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Let me know what you find or if you have other questions.

Take care,
Joe
May 27, 2019 at 2:22 PM
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