Coolant Temp Gauge Problem

[Neal_P]

I'm having some problems with my coolant temp gauge that I just got. Got the gauge all hook up but am not getting any reading. Looks like I have good power to it. When I turn the ignition on the needle jumps up to just under 100 degrees. I put the sender in a port on the coolant filter housing because the port on the waterpump is being used for my coolant filter. Even if it was not getting completely submerged with coolant I would think that it would raise the temp up a little. But nothing. I even tried boiling some water and putting the sender in it to get a reading and I got nothing. Even used a different sender. Nothing. Could I possibly not have good power going to the gauge even though it jumps a little when the ign. switch is turned? The gauge is an Autometer Z-Series.

 

[jlayne]

check your connection with a volt meter.. make sure to check the ground

i bet the sending unit isn't grounded since it wasn't mounted on the engine because what you mounted the filter head to wasn't grounded or was painted (not grounded) or if you used pipe dope that can booger up a ground as well.. either that or the gauge/sending unit is bad

to test the gauge/wiring up to the sending unit if the sending unit wire is grounded out (touched to bare metal) the gauge should show full tilt

you can check the sending unit with a ohm meter but right off the top of my head i can remember how much resistance is should have hot or cold... i know if it is hot the resistance will go down

by the way with the sending unit mounted off the engine in a low flow setting (coolant filter) your readings are probably going to be way colder than whats going on in the engine

 

[Neal_P]

check your connection with a volt meter.. make sure to check the ground

i bet the sending unit isn't grounded since it wasn't mounted on the engine because what you mounted the filter head to wasn't grounded or was painted (not grounded) or if you used pipe dope that can booger up a ground as well.. either that or the gauge/sending unit is bad

to test the gauge/wiring up to the sending unit if the sending unit wire is grounded out (touched to bare metal) the gauge should show full tilt

you can check the sending unit with a ohm meter but right off the top of my head i can remember how much resistance is should have hot or cold... i know if it is hot the resistance will go down

by the way with the sending unit mounted off the engine in a low flow setting (coolant filter) your readings are probably going to be way colder than whats going on in the engine

You were right. The sender was not grounded. I also went and got a tee to tie it in at the waterpump instead of at the coolant filter. Thanks for the help.