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Temp Gauge Intermitt. RED HOT

oilspill's Avatar
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09-29-02, 01:16 PM   #1  
Temp Gauge Intermitt. RED HOT

I have a Buick Century 1995 3.1L
This problem has been around since buying the car in '99 and nothing terrible has happened (yet?).

The temp gauge needle goes form the middle normal range to
the red - and sits there for a minute..and then quickly swings to the normal again...
This happens about 5min after starting the cold engine..
and continues back and forth as one drives.
Had thermostat replaced twice; then mechanic tried a new temp sensor but no change;
finally after checking cooling system out for several hours..
and left car overnite for more testing- he concluded that the temp guage was bad...which means the whole dashboard panel since sold as one unit..which means mucho dinero..

however, I am sceptical; whenever the guage goes to red..
the engine fan kicks in..
and I figured that the engine is telling the gauge and FAN that it's too hot..rather than the gauge telling the FAN it's too hot.

by the way..when the temp first goes red on cold engine start..
the engine really was cold since I checked it.

THanks !!!

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joelp's Avatar
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09-29-02, 01:27 PM   #2  
This sounds like it could be a loose ground somewhere. It will need someone who can trace things out.

Joe_F's Avatar
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09-29-02, 04:27 PM   #3  
Have the mechanic check the actual engine coolant temperature with a scan tool and compare it to the gauge.

If the gauge proves faulty, buy a new one from GM, a junkyard, or as mentioned make sure there is not a ground issue first.

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09-29-02, 05:00 PM   #4  
If it were my car I would replace the instrument panel cluster.If I wanted to fix the problem.Buy an aftermarket temp guage and install it .That way you will know the actual temp of the engine.

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09-29-02, 11:18 PM   #5  
i believe what you are seeing is the thermostat opening for the first time about five minutes down the road from a cold start up it will be most noticable when it opens for the first time and then you may notice it a few more times but it will be less of a fluctuation, within 10 -15 minutes the thermostat will be open all the time may close a little but never closes completely again until the engine is cooled back off.
all thermostats do this due to the fact that it has warm coolant on one side and cool on the other side of it which causes it to open late for example a 195 degree will usually hit 230 -240 before it opens for the first time the reason the fan is running is cause the engine is up to temp and is needed, although your upper raidiater hose may still feel cool the coolant in the engine will be hot.
factory guages were not made to be accurate i would just live with it and not be to concerned about it after all it has been doing this how long 3 years. but i would bet putting a lower degree stat in it say a 180 would probably get you out of the red and open for the first time in the 215 to 225 degree range just a little quicker than the stock one. it will still fluctuate though.

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09-30-02, 03:40 PM   #6  
got hot spot

You may have big gulps of air in your antifreeze circulation.Run engine at idle with rad cap off until no bubbles can be seen coming up the rad spout where cap screws on to.

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