Coolant temp gauge acting funny...

[540s10]

Whats it mean when the gauge on the dash starts movin like a seismograph or a lie detector needle?

 

[NVW]

I would first clean all grounds to rule that out. Then the sender.

 

[ak diesel driver]

if you have carcode or something similar check what the ecm temp sending unit is showing

 

[WarWagon]

Bad connection at the sensor. Possible coolant leak through the sensor. Bad wire rubbing or burnt through. Wire could reach/burn on the exhaust manifold on mine anyway.

Boiling coolant in the block... (bad water pump or weak radiator cap...)

 

[540s10]

i did notice that under hood was not very hot at all, and i could squeeze the upper radiator hose easily and watch the coolant in the overflow rise and fall

 

[racer55]

the stepper motors in the cluster have been known to have problems.
my fuel guage is doing a similar thing in that it will read the fuel level and be noisy for about 30 seconds and then shut off.
I have a stepper motor set ordered to change out all 6 gauge motors at once.
will try to update results when complete.
keep the previous seggestions in mind though also, but I am thinking sending unit connection or stepper motor/cluster connection.

 

[540s10]

i hooked my scan tool up and the ecu sender was reading properly, cleaned the connection on the sender for the gauge we'll see if that fixes it, if not I ordered a replacement from napa.

 

[STEVE53]

I had the same problem, temp would be reading fine then it would jump up then down again. I pulled my gauge cluster and cleaned the terminals on the cluster and the dash with electrical cleaner on a Q-tip. I haven't had the problem since.

Steve