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?

 

A thermostat works mechanically. When the coolant reaches the specified temp, it opens. You didn't put it in backwards, did you? Did you double check the coolant level?

The gauge just reads the temps. There is a sensor/relay that turns the fan on. You might try bypassing it to make the fan run constantly and see if that brings the temps in line.

If the head gasket blew you would either get coolant in the oil or out the exhaust = white smoke.

 

I'd want to hook up a scanner and read the temp out of computer state display.............I believe the computer drops the ground that triggers the coolant fans so I'd wanna know what the "magic box" is seeing.
As mark said, also check to make sure the T/stat is installed so that the "bullet" part is towrds the engine........Going to a "lower temp" T/stat is not such a good idea as these computerized engines are designed to operate at a given temp............Running a lower T/stat can give you an effect like a stuck choke on a carbed engine.......

 

Thanks for the advice about reading the temp from the computer - if I take the car to Autozone (or some place that will read the error codes for free), will that code reader be able to tell me what temp the engine is at? Also, as for a low temp stat, the parts store kept trying to sell me a 192 stat, but their own computer said the oem was 180 - so I went with the 180. The stat does open up and the fans come on, just they do so only when the gauge is already close to over-heating. Shouldn't the stat open up at just about middle on the guage and the fans turn on midway up the gauge - not waiting until the very last moment before the car over-heats. Since both parts aren't doing their job until the guage reads very, very hot, couldn't it be the gauge or the sendor? Especially since I had just replace the sendor? And when I replaced the sendor I wrapped the threads with teflon tape, will this tape interfere with the conductivity of the sendor?

 

I'm not sure if Auto-Zones code reader will access serial data.........but it never hurts to ask. Never worked for a Ford dealer so, offhand I don't know what the turn on temps are for your car........G.M. vehicles equipped with temp controlled fans turn on at 230 deg/fah............Overheat is 260.......so there's not too big a spread.........Ford may be about the same???

 

If the sender is a one-wire type you may have affected the reading with the teflon tape; if it's a two-wire, probably not.

 

I've a 96 Mercury Mystiqie that had a similar problem with temp gauge. I changed the sending unit and still had the problem. So I changed the gauge in the dash (about $20 from the dealer) This fixed it. Just a thought.

 

He seems to have an overheating problem, though, not simple indication error.

Have we established for certain that it's not a blown head gasket???

 

1"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" "2"Any suggestions? Is there a way to measure the real temp of the engine?"


Sounds like he's not sure if it's overheating or if the gauge is off.

 

You can 1 0f 2 things remove the cap when cold and let car heat up and stick a mecanical thermometer in the neck or you can use a infrared lazer style thermometer and point it at various parts of the engine like the hoses and radiatior. The scanner auto zone uses will not tell you the engine temp.

 

My bust, Dan; had to go back and read it three times to make sure I was on the right wavelength.

Side note on taking the temp reading mechanically; don't use the wife's meat thermometer, the coolant is toxic.

 

"don't use the wife's meat thermometer, the coolant is toxic."

and you don't want to make the cook mad

 

Did you make sure you have enough coolant protection against boil-over? Plus, make sure the fins inside the radiator aren't clogged. You can look into the fill hole and see if they are squirting out when thermostat opens. Plus make sure there arent any leaves or anything clogging the exterior of the radiator. Plus you can take your hand and feel all around the outside of the radiator and feel for cold spots, meaning no flow in that spot such as a clog.