low coolant light

[duckrock]

I have an 81 Chevy K20.
I just put in a new motor. Radiator was replaced at the same time. Now I have a low coolant warning light on dash. The coolant is not low but the light remains on. Any ideas?

 

[tech1]

You might want to lose the light and get a gauge for it instead

 

[duckrock]

I don't really want the light or a gauge. I just want to know where the sensor is that makes the light - light so I can make the low coolant light go out.

 

[MarkyB]

Are you sure this is a "Low" coolant indicator?

If so, I'm guessing it's located on the driver's side of the block, just below the #1 and #3 spark plugs. There should be a dark green, single wire connection to a coolant temp switch. This was typically used from '77 through '87. Before unplugging it, trace the wire backwards to make sure it's not touching the exhaust manifold or any other metal. The loom around that wire has most likely deteriorated over the years, and may have caused the wire insulation to deteriorate or melt as well. If it has, this may be your problem with the light. On the other hand, if the wire looks ok, try to unplug it and see if that turns off the light.

 

[zip]

From 73 to 87,all 305,350 and 400 engines were s'posed to have a thermostat housing with an coolant temp sensor port. Could this be the sensor sending the 'low coolant' warning?