Preheat oven to 350 degrees.
Saute onion in oil, add flour, milk and chili.
Cook until medium thick.
Reserve 1/4 cup of cheeses to sprinkle over top of sauce.
Heat 1/2 to 1 tsp of olive oil
When oil is warm quickly dip tortillas in oil until soft and warm.
Immediately put 1 Tablespon each of cheese, crabmeat and sauce in tortilla and roll up.
Place seam side down in a 11×7 inch pan.
Repeat until all tortillas are used.
Pour the remaining sauce on top and sprinkle with reserved cheeses.
Bake in preheated oven for 40 minutes.