I know it's not a truck but it is a Mod motor and I really need some help.

I have a 97 Lincoln Continental 4.6L DOHC that is over heating.

The car will idle for hours and cruse up to around 45 MPH with no problems. From there up the temperature will climb with the speedometer and eventually I get an hi-temp warning. If I let off and coast down the temp goes right back to normal. Holding a steady speed at 50 to 60 MPH will cause the temp to go up high.

So far I have replaced the entire cooling system; water pump, thermostat, hoses, belt, tensioner, radiator, temp sending unit, and cooling fan motors. I even removed the water pump and tack welded the impeller to the shaft (thinking it might be slipping)

Thinking it might be an engine management issue (maybe running lean) I also replaced all 4 O2 sensors,installed a new throttle body, TPS, Traction Control Motor, TC Position Sensor, and swapped out the ECU.

No codes show up. I am not losing coolant; no water in the oil an no oil in the water.

The engine runs fine. No pinging or power loss. Exhaust flow at the tail pipes seems to be normal, however the exhaust temp seems to be somewhat elevated.

So I am out of ideas. Anyone have any suggestions?

Thanks in advance.

 

It makes no sense since the engine should remain cool at any speed over 40mph without the Efans running. I know someone who also had their '96 overheat and I think it had to do with the fan control, but it wouldn't overheat at highway speeds. I think it may be common and there could be some TSB's on it

 

I guess the only thing left is the exhaust... Well the only thing left that you haven't replaced...

I would be pulling my hair out!

Good luck!

 

Have you checked for a headgasket problem?