I have a 2006 chevy trailblazer with a v8. I recently
replaced the water pump and the thermostat. Now
after u drive for a little while when you stop you
hear bubbling in the resevor. Sometimes it's
actually hot and sometimes it's not. ( the water in
the resevor) and yes right now it's water. Ok so
why or what would make this happen.
You might still have air trapped in the system.