Had thermostat replaced, guage still red lining after driving about 15 or 20 miles. Had sending unit replaced, still problem. Am being assured the van is NOT running hot according to the computer. However, after driving about 15 miles or so of stop and go driving the needle on the guage will gradually move to red line. Turning off all air air and fans seems to make the needle come back down. Also (soooo strange) needle seems to come down when you apply brake and slow down! Any suggestions?