2003 Chrysler Concorde Engine temp sensor jumps around

2003 CHRYSLER CONCORDE
65,500 MILES • 6 CYL • FWD • AUTOMATIC
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JYEARY
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After driving about 25 miles, the temp gauge will float or sometimes jump from normal (center) to a higher temp reading.

It can go from normal to the next hotter level (60% of scale), stay for 5 to 10 seconds, then may come to center and then move back up to the same or hotter indication. There are times when it comes back to normal, but in general when it starts floatling, it only goes higher till it shows hot for about 5 to 10 seconds and will come back down to a lower reading. Some times it will come back to normal for a few miles, and then start to show hotter temp again.

The needle does not moge slowly and smoothly. It sort of jumps from one temp to the next, both up and down.

Once this starts it will do it on the road, or at Idle, and with cool temp's (45 F).

I've just got the car and don't have a lot of background on the car.

My first thought was it was a temp sensor. I looked on line and found that this engine 3.5 L and the 2.7 L engine has a history of getting sludge in the engine and reducing coolant flow.

I had the lower engine block flushed today, and the Radiator was flushed about 5000 miles ago. It didn't appear to have helped.

I should have had the thermostat replaced, but forgot to tell them to do it with trying to get the engine etc. stuff set up.

At the dealer, it's about $250 to change the temp sensor.

Any comments or other help? Can I change the thermostat without loosing coolent and gettng air in the system?

Thanks for any help you can give.

James Yeary
Dec 31, 2007 at 12:23 PM
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MERLIN2021
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You are asking for the wrong part, the ect is not what you need, you need the temp sending unit, probably about 20.00! You should change the thermostat, may fix the problem! And is your coolant full? You can get needle swings like this when there is air trapped in the system.
Dec 31, 2007 at 2:01 PM
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JYEARY
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merlin

I don't know what the ETC unit is?

I do know what a sender is, but not it's location.

Can I change it myself without ripping off the tip of the engine?

Coolant tank is full to the max mark cool.

I will change the thermostat soon.
Dec 31, 2007 at 5:44 PM
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MERLIN2021
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It's mounted in the water jacket near the thermostat housing, thats at the end of the upper radiator hose...it seems Chrysler only uses the ECT Electronic collant temp sensor, your engine is 3.5?


https://images.2carpros.com/forum/automotive_pictures/62217_35_2.jpg

2.7
Jan 3, 2008 at 3:15 AM
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OLDCARPRO
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I just ran into this exact same thing on a 2003 Chrysler Concorde and I switched the two fan relays out and the problem disappeared. Which one was the problem I do not know but here is a suggestion for you to try; switch the relay with the gas pump relay to see if the problem goes away. I intend to replace all the relays just for preventive reasons.137,000 + miles.
Aug 9, 2015 at 5:05 PM