10 to 15 min of driving in moderate city driving conditions (revs under 4k) with outside temperature ranging from 35-55F causes the engine to overheat. The temperature gauge goes up and down in the range between normal and almost boiling (red line).
In a previous thread I have rulled out the second fan isn't supposed to be working so it means that once a higher temp kicks in one of the fans comes on properly.
The cooling system is filled up properly with the coolant level at 'max'.
I notice that the temperature goes up mostly when either stopped in a traffic or moving very slowly.
One thing to notice is that I was involved in an accident 2 months ago and the radiator had to be changed. I was assured that the shop uses only genuine and brand new subaru parts so I doubt the core is bad.
The only thing I may question is the quality of the coolant. I know subaru requires special genuine subaru coolant since the engine is made of aluminum. And I doubt the shop went as far as using the right coolant at the exact proportions. So that's one thing I may look into.
Other then that anyone has any other suggestions? Can the thermostat be a primary suspect?