drain the rad in a new clean drain pan see if it has any oil in it. have not check prices lately, ebay has head re-builders, seems weird all are low with not oil, even the 80 on #1 is low, I think normal is about 180, is yours 180 and not 80 ?

2001 5sp. K&N stock filter 215/70/15
If your check engine light is on at least you know the light still works