Hello all :-)

So I have a 1997 BMW 528i, 83K miles. Last January, I noticed the temperature gauge work towards the "red zone" when I was stopped at a red light or in traffic, and when I accelerated it went back to normal. Carmax replaced the thermostat and bled the coolant, and replaced it with new coolant. It worked for 3 months, and then the same thing happened again. This time, Carmax replaced the cooling fan clutch. Now it is doing the same thing again. What is going on? I also have started to hear a roaring noise when accelerating from a cold start, and although I recently had the transmission replaced, there is still a sharp kick when switching gears.

Has anyone done a pressure check on your cooling system?
Your system should hold a minimum pressure that's stamped on your radiator pressure cap overnight. Nearly all mechanics have this special cap / hose and small air pump to test your cooling systems ability to hold pressure. The same tool checks the pressure cap on your radiator.

If the pressure tests check out OK, I'd do the two part granular acid flush and neutrilizer to the radiator and cooling system or replace the radiator.