I have a 03 v10 that the heat guage keeps showing hot and then goes in safe mode.Never know when it is going to do it and cannot find a reason. Put a new thermostat first no luck. Then temp sensor, again no luck. Just swaped the ecu and still doing it. I have a temp gun and when it goes into safe mode the head temp is around 170. Turn the key off and back on and the temp is normal and out of safe mode. May run a week or may run 2 minutes until it does it again. If its a wiring problem why does turning the key off reset it? Any ideas? Thanks
Check the clutch fan. This will cause an ingine to run hot. I just went though this last winter. The temp would rise to 270 and stay and climb a bit. I would pull over and shut it off and wait for it to cool down. Sometimes upon restarting the temp was back to normal and sometimes it stayed high. It would no this with no indication. It would go a couple weeks and be fine then boom,,,,270 degrees. I did the same as you and eventually took it to a mechanic and found the clutch fan was not operating correctly all the time. Changed the clutch fan and perfect.
Just a place to look.
Good luck.
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03' F-250, XLT Sport, V10, Banks Powerpack, SVT 18x8 wheels, and Toyo Open Country A/T 285-65-18E
09' F-350, XLT, V10, Regular Cab
I understand, this happened to my work silverado. While the guage read 270 the engine was not hot. You could open the expansion tank by hand. The truck would go into limp because the guage was stating hot. While I didn't have a fancy temp gun I could tell by lifting the hood that it was not running hot. There was no evidence of over heating. Like I said you could open the expansion tank without any danger.
Just a thaught.
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03' F-250, XLT Sport, V10, Banks Powerpack, SVT 18x8 wheels, and Toyo Open Country A/T 285-65-18E
09' F-350, XLT, V10, Regular Cab
Testing the clutch is pretty simple. I have changed a number of fans on my work earth moving equipment. Most of the time the spring has failed. On my chevy I am not sure if it was the spring or not.
Did you change the cylinder head temp sensor? A long time ago, one or two people had this exact same thing, and it turned out the PCM was bad, but don't go jumping to conclusions
It could even be an air bubble in the coolant.
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- art k. - Moderator for the Superduty, V10, and FE forums
'01 F250SD SC SB XLT V10 4x4 auto 3.73 Warn hubs Volant CAI, eBay headers and y-pipe - 5-star custom tunes on SCT X3
'97 Cougar XR7 30th Anniv Edition 4.6L
'74 F250 Highboy FE390 deceased! I've been wrong before, I'll be wrong again. Just wait and see.
Art, when I had my issues I too thaught about air in the coolant. I even jacked up the front end up as high as I could and idled the engine with the expansion tank cover off to let any air escape.
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03' F-250, XLT Sport, V10, Banks Powerpack, SVT 18x8 wheels, and Toyo Open Country A/T 285-65-18E
09' F-350, XLT, V10, Regular Cab
Changed the temp sensor and swaped the PCM with another truck,still doing same thing. Talk to a mechanic at the local ford dealer and he said try the insturment cluster but he also said that the truck would have to be reflashed to run. He also said that he couldn't believe that the truck ran after we swaped the PCM and didn't have to reflash it. Anyone know if this is true or not? Also had a mechanic check out the clutch fan he said it was good. It would spin with engine cold and when the engine warmed up checked it again and it was hard to turn.
If you swapped the PCM from a truck that is the same year and engine, well, chances approach 100% that it'll run.
Check the wiring, sounds like something is shorted or open.
__________________
- art k. - Moderator for the Superduty, V10, and FE forums
'01 F250SD SC SB XLT V10 4x4 auto 3.73 Warn hubs Volant CAI, eBay headers and y-pipe - 5-star custom tunes on SCT X3
'97 Cougar XR7 30th Anniv Edition 4.6L
'74 F250 Highboy FE390 deceased! I've been wrong before, I'll be wrong again. Just wait and see.
Ok now I have found that the expansion tank is filling up and running out. The engine block temp is around 180, the head temp around 165 ,the radiator is around 135 ,coolant at the hottest in the expansion tank is 153,Bottom radiator hose 103. No oil showing up in water or water showing up in oil. Temps aren't hot. Still all you have to do is turn key off for 5 sec turn key back on good to go,for a little while. The gauge will heat and cool on its own several times very quick. If it helps 03 v10 with engine block heater. This is about to drive me nuts.
Pulled the codes have a P1285 and P1299. The computer is showing it reached 255 degrees. I have shot every possible place with temp gun nothing is giving a hot temp really not even getting normal temp.
Funny how "255" is exactly 8 bits of 1's. In other words, it's the highest number in binary that can fit in 8 bits.
__________________
- art k. - Moderator for the Superduty, V10, and FE forums
'01 F250SD SC SB XLT V10 4x4 auto 3.73 Warn hubs Volant CAI, eBay headers and y-pipe - 5-star custom tunes on SCT X3
'97 Cougar XR7 30th Anniv Edition 4.6L
'74 F250 Highboy FE390 deceased! I've been wrong before, I'll be wrong again. Just wait and see.
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