Coolant system temperature sensor(s)

2005 SATURN RELAY
186,000 MILES • 3.6L • 6 CYL • 2WD • AUTOMATIC
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JIMMYSTEW2CARPROS
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  • 1 POST
Background:
(1) ... No coolant leaks
(2) ... Engine not overheating
(3) ... Gas mileage not really changed
(4) ... Engine running fine

Symptoms:
(1) ... Coolant fan running almost constantly and goes on and off at unusual times.
(2) ... At the same time that the coolant fan issue started the temperature gauge started acting goofy! Even when the engine is cold at start up the temperature gauge (even before getting warmed up) the gauge will move to high temperature indication and then slow back down to normal and below.
(3) ... It will also do this sporadically even when engine is hot after traveling and then settle down!
(4) ... All the while the fan is running most of the time!

Thank you!

Jimmy stewart
Oct 11, 2018 at 8:14 AM
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STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Hi Jimmy,

It sounds like the engine coolant temperature sensor needs to be changed. Here is a guide to help you through the steps and diagrams below so you can see how to replace the sensor on your car:

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

The sensor is down low on the cylinder head near the rear of the engine.

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Cheers, Ken
Oct 12, 2018 at 10:51 AM
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