About 2 weeks ago i was coming home from work around 6am doing about 65-70mph with outside temp around 55*F on a slight up hill when i noticed my temp gauge start going up. i caught it on the line right above 80*C (not sure what temp that is) and turned the heater on full. temp started dropping and sat right above 80*C.

fast forward to now, takes about 30min at idle for car to get to the line above 80*C. if i accel the pedal for a while temp starts to drop. if i'am on the freeway on a flat surface going between 40-60mph car runs perfect at about 80*C. if i go above 65mph or hit a hill temp start going up. if i get off freeway and hit stop and go traffic, temp climbs up again. so far i have not lost coolant and have not let it get passed the line above 80*C and if it does i turn the heater on (never let it get close to the 120*C). i also noticed that the front Aux fan does not turn on even when direct connection. before this car ran at around 80*C all the time with no issues.

just wanted find out were i should start first since you guys have more experience with this problem on the om603 with a #14 head. i hope its not the worst news: