2002 lincoln navigator. 5.4l What would i expect the cyl head temp to be (on modis scanner) if my ect is at 180 deg.
Im seeing 270 @ cht sensor. Warmer if ac is on or rapid accel up hill. Will boil water in degas bottle. Coolant will leak from degas bottle cap. Cap was replace with oem cap. New water pump, found original pump impeller failed, all blades missing. Engine ran as should for several days after w/p replacement. Then started overheating. Replaced tstat. Problem persists. At idle ect @ 180 and cht @255 then at 45 mph ect @ 200 and cht @ 280. That seems too hot. But dont know what they should be. Please help

 

Your engine does not have an ECT sensor. The ECT_PID is a calculated or inferred value based on the CHT sensor.

Use an IR thermometer to measure he temperature at the thermostat housing. That way, you'll be able to determine if your engine is actually overheating or if your have a problem with the accuracy of the CHT sensor. Once you know the true state of the engine, it's easier to provide a sense of guidance and direction

 

I return to work tomorrow. Ill check with my ir temp gun. Btw coolant leaks from cap threads of degas bottle when hot. Cyl leak down test ok.. Any thoughts? Ill return with resluts of temp check tomorrow. Thx for your help!!

 

Now I'm a little confused. My ford dealer, Snap on dealer, and my Svc Mgr all say there is an E.C.T. sensor and a C.H.T. sensor. 2 different part numbers. the E.C.T. is larger in diameter than the C.H.T. sensor. I can easily see the E.C.T. sensor below the air box. I checked with my I.R. temp gun below the area where the E.C.T. threads in and the ect_pid on my modis is only 5 deg difference from what i see on the temp gun. checked for hot spots in radiator.... very consistant temp across the radiator.

My Svc Mgr (plz note: that this was done cold and at full temp) held the fan with a plastic hammer handle while I started the engine and was able to hold the fan blades stationary with his hand without effort with the engine @ idle. after letting go of the fan and letting it turn normal speed at idle, we could carefully slow it down and stop it again. I could even turn it backwards. btw, pressure checked cooling system ck'd ok... What Y'all think

 

One of the following is wrong:

1. All of the Ford factory service documentation. Wouldn't be the first time....
2. All of the listed in the quote.
3. The identification of the subject vehicle as a 2002 5.4L.



Sounds like the fan clutch is worn out.