I have a 1992 VW Passat 2.0 DOHC. I have relplaced everything I can think of in the coolant system and the temerature is still reading about 230 degrees at times. I put a OEM 185 degree thermostat in it and have checked the thermostat more than once. I am not leaking coolant and I just put a new water pump in the car a month ago when I did the timing belt to save time. I have 50 50 coolant in it and have changed the switch for the fans and have proved that they do come on. The only one that I have not changed is the switch for the gauge but I haven't changed this because when it is at 230 you can hear the fans running on high so I would think that is a good indication that the guage is at least close to correct. I am really at a loss with this and I was just hoping that someone else once had this problem and fixed it. The car never actually overheats though. And I just did a head job so yes I did replace the head gasket again with OEM parts. Please someone let me know what you think!!!! Thanks.