ok so the other night it was rather cool outside and i had the heat on low as i was driving around town and came to a stop i noticed the temp go up rather quickly. it stopped about 215-225 area my cooling fan kicked on but did not seem to do much. i checked for leaks and the fluid level and all seemed fine so i hit the highway for the drive home and the temp went back to normal and has since stayed so. the next day i checked all again still no evedent sign of something wrong but i did notice a milky like film ontop of the antifreeze in the resivour. of course thought head gasket checked oil no sign there. my heat seems to take its time to warm up and i am really thinking the thermostat may be bad i have ordered one and will change the antifreeze as well. but car does have 221000 miles on it and am really hoping it is nothing major i drive it daily and would hate to have to make i a weekend car.(it gets mad when not driven). any comments or suggestions would be appreciated....