I drained the old coolant out of my 2011 ec 300 today, and as I tightend up the drain screw, the little fiber washer on the screw split rendering it useless. I went around town looking for a suitable replacement and found none. So....I just tightend the screw back in without a washer and it seems to be working fine (no leaking). Should this be ok or did I screw up?