Air passages in LIM
I changed the LIM gasket a week ago. Everithing went fine and my coolant leak appears to be gone.
I noticed something when I had the LIM removed. The air passages in the LIM (and UIM) were black for cylinders 6 and 5 and they were gradually lighter towards the front of the engine. Cylinders 4 and 3 had the air passages brown to light brown and cylinders 2 and 1 had a light yellow to aluminum silver color.
It appears that cylinders to the rear of the engine are running hotter than cylinders at the front of the engine.
Is this normal?
I don't know if it is related but my car has been blowing the NOx limits for the past 3 years (running too hot?).