coolant temperature gauge bounce up and down.
your post is a statement; is there a question?
more info please. Either bad sensor, bad gauge, or not enough coolant. Need the Year and milage and model.
With Car At Operating Temperature, With Cabin Heat Temperature And Fan On Full Blast, Is There Any Change In Heated Air Temperature ( Ranging From Cool To Hot ) While The Gauge Is “Bouncing” Up And Down ?
1997 nissan pickup 2.4 liter heater work great no change in temperature when gauge bounce.truck has 208,000 mile.i bleed system to get any air out.but gauge still bounce.
Does it bounce while just sitting, like at a traffic light or only when moving? If only when moving, then the gauge itself may have a problem with its internal dampers. It could also be a dirty connection at the sensor or the sensor wire may have an open or short.
Is the bounce rapid, like every second or two or is it slow, like 15 seconds to a couple of minutes?
Is the bounce primarily upwards toward the hot or downwards to the cold or full scale, hot to cold?
Maybe you should find at least one of your older posts about this and respond to it with an update of where things stand. This can save people a lot of unnecessary trouble. There’s a Search feature at the top of the page that will help you find you old posts.