The Ford Barn

thekid1950 · 08-16-2023, 08:27 PM

1951 Ford Flathead
Temperature gauge before start up..............H (as it should)
Gauge after start up........................................C (as it should)
Gauge after warmed up engine.....................C+ plus a very little (malfunction)

Shut engine off....turn on key......temp gauge now shows proper temp.
Start engine again............................................. C+ plus a very little (malfunction)

Changed both temp sending units with known good working ones....same result as above.

Help!! Any ideas???

ford38v8 · 08-16-2023, 10:59 PM

Too much Teflon tape creates a grounding issue at the senders. Leave off the Teflon and use pipe thread dope instead.

19Fordy · 08-17-2023, 01:18 PM

Can you by pass the ignition switch? If so, then start the car and see what happens.
Perhaps switch is faulty.

Don T · 08-17-2023, 03:24 PM

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It is normal for a flathead temperature to rise after it shuts down. I think we need to know more about your thermostats and how you determined actual temperatures: assuming there is a problem.

08-16-2023, 08:27 PM	#1
thekid1950 Junior Member Join Date: Dec 2016 Location: Central NY Posts: 1	1951 temp gauge issue 1951 Ford Flathead Temperature gauge before start up..............H (as it should) Gauge after start up........................................C (as it should) Gauge after warmed up engine.....................C+ plus a very little (malfunction) Shut engine off....turn on key......temp gauge now shows proper temp. Start engine again............................................. C+ plus a very little (malfunction) Changed both temp sending units with known good working ones....same result as above. Help!! Any ideas???

08-16-2023, 10:59 PM	#2
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,646	Re: 1951 temp gauge issue Too much Teflon tape creates a grounding issue at the senders. Leave off the Teflon and use pipe thread dope instead. __________________ Alan

08-17-2023, 01:18 PM	#3
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,950	Re: 1951 temp gauge issue Can you by pass the ignition switch? If so, then start the car and see what happens. Perhaps switch is faulty.

08-17-2023, 03:24 PM	#4
Don T Member Join Date: Mar 2017 Location: Alberta Canada Posts: 93	Re: 1951 temp gauge issue Sponsored Links (Register now to hide all advertisements) It is normal for a flathead temperature to rise after it shuts down. I think we need to know more about your thermostats and how you determined actual temperatures: assuming there is a problem.