Engine temperature gauge stopped working but gauge goes up with Engine hot and turned off, ?

[Paul Chappell]

Hi, Thanks in advance,.
Has any one had this issue before? I have a C2 1966 5.3l, temperature gauge has stopped working but gauge goes up with Engine hot and turned off, when engine running gauges does not moving, turn engine off when warm gauges moves up but not sure its the right temperature shown.
just looking for a starting point , I haven't started any diagnosis yet other than the wire is on the sender,
Thanks Paul.

 

[teamzr1]

Hi Paul

You need to find out if the ECT issue is with the sensor in the block, a wiring or ground issue or is it the gauge itself

You can do this with this chart using an OHM / multi meter
The sensor in block puts out a resistance value

So for example if you put one probe of the OHM meter to ground and the other probe to the output of sensor
if the OHM meter reads 40 OHMs as you see in this table, that would equal 140 C / 290 F degrees

You could take the wire off the sensor and do this test just as the sensor would tell you if it is OK
The lower the resistance value is, the higher the ECT is
IF reads about correct, then you need to do the same test at the point that wire from ECT connects to temp gauge
as that would tell you the output wire of ECT is good or not
If it matches what was measured at ECT sensor than the issue is with the gauge
sometimes it could be a weak ground to gauge, else gauge is wacked up

Make sense to you ?

 

[Pitre]

There was an article by Chris Sale in Vette News (October 2021 edition) regarding C2 temperature guage calibration, now available to download from our new archive of articles here:-

https://www.corvetteclub.org.uk/resources/c2-temperature-guage-calibration.181/

 

[Oneball]

Check your coolant level is correct and that your pump is pumping.

 

[Paul Chappell]

Hi Paul

You need to find out if the ECT issue is with the sensor in the block, a wiring or ground issue or is it the gauge itself

You can do this with this chart using an OHM / multi meter
The sensor in block puts out a resistance value

So for example if you put one probe of the OHM meter to ground and the other probe to the output of sensor
if the OHM meter reads 40 OHMs as you see in this table, that would equal 140 C / 290 F degrees

You could take the wire off the sensor and do this test just as the sensor would tell you if it is OK
The lower the resistance value is, the higher the ECT is
IF reads about correct, then you need to do the same test at the point that wire from ECT connects to temp gauge
as that would tell you the output wire of ECT is good or not
If it matches what was measured at ECT sensor than the issue is with the gauge
sometimes it could be a weak ground to gauge, else gauge is wacked up

Make sense to you ?



View attachment 22887

 

[Paul Chappell]

Thanks for the great information will do some testing,
Paul.