After reading thru all of the related issues already written on this site, I attemped to track down the problem with a temp gauge that was giving me either an extremely low or no water temp reading. I changed the temp sending unit, I grounded the temp gauge wire (and got the gauge to peg over to the right), I cleaned and checked the ground connection, I checked the ICV regulator, and got the the proper "bouncing" signal. All the other gauges seem to work ok. So dumbfounded, I thought perhaps it is not the gauge........When I ran the car to check the gauge earlier, it was suddenly running rough and occasionally hestitating............I then thought perhaps the thermostat has failed and the reason for the rough running and low temp gauge reading was really because the thermostat wasn't closing, and causing the truck to never get up to the proper operating temp (I didn't run it that long and it's been unseasonal cool here in Atlanta the last few days). So my question is "oh great wise Ford Truck guys", could this be causing my problem? If not what else should I check? I need to get it running with a reliable temp gauge (as reliable as these things get) by Thursday. Thanks

By the way this is a 1978 F150 witrh 460 motor/c6

 

Things to check:

1)Coolant level in Rad.
2)Use a meat or candy thermometer to check the temperature of the coolant when you get a maximum reading on the gauge.
3)VERIFY what degree thermostat is installed.


[b][i][font color=red]Dennis[/font][i][b]
[font color=red]Calgary,Alberta,Canada[/font]

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Well here's something you can do right away. When the engine is truly cold, start her up. Hopefully it will kick up on the fast idle cam. Now carefully remove the radiator cap and look at the coolant, it should be stagnate. It should remain that way for a while until the first puke of coolant passes through the stat. Then it should slow down as the stat closes again for the next puke. The stat will find a happy medium as your gauge moves into the normal range.

If it's flowing right away, then I think you found your problem.

Barry

 

T,
Is your problem that the temp gauge doesn't read high enough?
Does your vehicle show symptoms of running hot?
Does your fuel gauge work correctly? If so, the circuit for the temp gage is probally fine.
My vehicle runs a little rough when cold. After a minute of idle it runs fine/OK. My choke doesn't work. Most motors can run fine through a wide range of temps.
My gauge is all over the place depending on how and where i drive. My radiator is questionable.
Your best bet is to get a second opinion. Hook up a second gage that is calibrated(has numbers) and see what you get. There are many reasons for a rough running engine and a low temp gage is not enough explanation to render an educated guess.
My Way is the Highway,
KingFisher