[goldguilexx]

So i have had an issue with my cooling sytem for about over a month now. Ive replaced my water pump, the thermostat, the sensors, the upper and lower hose and the expansion tank. the only thing left to replace is the radiator and the fan. The mechanics ive taken them to both say they are fine and dont need replacing but at this point im just going by the process of elimination.
The car will be running normal temp (temp needle pointing straight up at 12 o clock) and then after the car has warmed up for say 20 minutes or so the needles starts to go to the right (towards the red) when idle on a stop light or something. The fix was to rev the engine to about 2k rpms and make the coolant flow due to lack of circulation as it seems and problem fixed till the next light. then the process would start all over.
A week ago one of the mechanics replaced a aux fan switch and the issue went away for a week end and sure enough it started back up. I made sure the radiator had enough coolant/water in it and that does not seem to be the issue.
Now the reving up to 2k trick does not work so i open up the bleed valve and let the steam air come out. Upper hose is hot and the expansion tank is as cool as a cucumber. Other than that issue the car has always run perfect, no other issues.
Last thing, air always seems to be inside the system, so im assuming an air pocket is trapped inside and wont budge out maybe.

Anyone have similar issues?


2004 bmw z4 3.0i roadster 100k+ miles automatic, out of warranty