I am having the save issue. I have not taken it in for “mis-diagnosis” yet. My question back to you is, do you have heat inside the car? I do not have any heat when I have the overheating problem. I have replace the water pump, thermostat, flushed the radiator and still no luck. When this first started happening, it would overheat and the heat wouldn’t work in the car, then all of a sudden the engine temp would drop instantly back to normal and the heat would come on. Now though the enigine overheats to the point of about 2/3 and then drop down and then work back up again. Could this be a sign of a pressure problem in the cooling system? How does the no heat relate to this?
Your asking if erratic temp gague operation,erratic heat output,occasional engine overheating are conditions related to the cooling system,yes. The question of if it is a “pressure problem in the cooling system” needs clarification,what are you getting at?
Did you purge the air from the system? Air pockets cause all kinds of problems like this. Also, double check the thermostat. I know it is new, but even bad ones slip through quality control.
That’s exactly what it was. Shortly after posting I talked to a local “quick lube” owner that does coolant system work. He said he’s seen it before and sounded like a air pocket. His suggestion was to start it up, remove the radiator cap and “message” the upper hose. Did this for a while and you could start to feel the hose getting hot. I let it run for awhile and the turned off and let it set for awhile and the restarted and ran it through a drive around town. I had heat and the engine didn’t overheat at all.