Replaced ECT and now before cranking guage reads 260, after cranking (and running for 60 second) falls to 210. 60 more seconds reads normal. After a few days it no longer holds normal reading it just does the cycle stated above and then pegs 260 then drops and stays at 210. Once in awhile it regains normal temp but after getting into 2nd gear pegs hot then drops to 210 and stays. Plan to pull ECT and wrap heat bonding teflon on threads and antisieze then re install. Anything else to maybe look into? Before buying another sensor and upgrade to tstat to aluminum single unit tstat and housing .. DIYer so I know it's unlikely to get solid response, given the site promoting shops, however maybe a decent mechanic will respond and have experienced similar and know what to do. Thanks in advance.
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The instrument panel (IPC) actually receives its temperature data from the engine/powertrain computer (PCM).
So, the only way to confirm what temperature reading actually is to use a diagnostic scan tool that can read live data, this will allow you to isolate the point of failure.
So, if the engine computer is in fact seeing temperature readings that high, then you could have an issue in the wiring for the sensor.
If the engine computer is actually seeing normal temperatures, then the issue is likely in the instrument panel, usually very evident during the 'sweep' that occurs prior to start-up.
If you see any of the needle pointers, stuck, slow, or otherwise acting erratically this is likely the case.
If the scan tool has bi-directional control capability, there may be a test called IPC Gauges Output Control which could aide in your diagnosis.
If you have any other questions feel free to give us a call at (877) 913-1554
Dusty
