I have a 97 Ford Contour, V6, Auto, a/c. It had a over-heating problem made worse by a bad temp gauge sendor so you couldn't tell it was overheating. I replaced the thermostat, waterpump, the temp gauge sendor and the engine temp sendor. Now the water circulates and every thing seems normal except that the temp gauge will read at almost over-heating (on a scale of 1-10 with 10 entering the over-heat reange on the gauge, the gauge stays in the 8.5-9.5 range. My first feeling is that when it over-heated either the head cracked or the head gasket blew. However - the thermostat does not seem to open up until the temp is very hot (say 8 on the 1-10 scale) and the electric fans don't come on until the engine is also very hot - again on a scale of 1-10, the fans don't come on unitl 9. Since the thermostat doesn't open up and the fans don't turn on until the engine gauge reads almost over-heating, maybe the temp sendor or even the gauge is bad - has this happened to anyone? Is this just wishful thinking and the head is cracked? A couple of other things - I see no coolant in the oil and no oil in the coolant. The instructions I had said to wrap the sendor with teflon tape - maybe that tape is interfering with a correct reading. And I can tell the thermostat opens and the water is circulating by feeling the hoses after it and I can see water circulating in the sealed system overflow tank. When I replaced the thermostat, I used the lower temp 180 stat. A bad gauge/sendor would explain why the stat and fans don't come on until the gauge says it is almost over-heating. Any suggestions? Is there a way to measure the real temp of the engine?

I want to buy a fuel system cleaner to add in my gas tank but there are so many different brands. Can someone recommend a good one?