[brucepick]

I use far more grill block in winter than in summer. I wouldn't have it any other way. I use removable bits to adjust it as needed.

With outside temperatures below freezing, the opening on my car is only about 5" x 6". But I have to pay attention, when temperatures rise up into the 40s and 50s I need to reduce the grill block or risk overheating.

Use your scangauge to show engine coolant temperature. I think the display is labeled ºFWT (water temperature). Observe for a few days with your grill block as it is now to see what temperatures it settles in at. Learn what temp your rad fan comes on at. Then when you increase your grill block you'll have a frame of reference.

My own engine settles in around 195ºF in moderate weather, with a 180º thermostat. Last summer with a 172º thermostat it stayed around 182º. If I block the grill too much it goes up over two hundred (still OK in my opinion) and has occasionally gone scary high.