The coolant temperature gauge in my 89 crx with a recient b16 swap is working really strangely. First off it takes a really long time to even move from the totally cool position and then after it warms up to normal operating temperature it randomly drops down to the totally cool position. Any ideas of what could be wrong?

 

maybe its your thermostat sticking open and not the gauge at all. I would start there, thermos are cheap!

 

Replacing the thermostat fixed the problem.

 

your welcome