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Discussion Starter · #1 ·
OK... I grounded the sending unit wire and the gauge pegged, so I then got a new temp sending unit and it started to register...
My question now is, where should the gauge stop when registering the temp? What is the "normal" temp?
My gauge stops to the right of top dead center, about half way between top dead center and hot... It is hot here in texas and the radiator has been flushed with new anti-freeze put in. Is this normal or could there be another problem.
I have nothing to judge it against since I have just inherited this car.
Any input would be helpful.
Thanks,
Jeff
 

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Go for a drive, have plenty of air flowing through the radiator, the needle on mine sits about 1/2 way.

Do not overfill the radiator either, make sure you have a 7lb radiator cap.
 

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Sounds on the high side to me. You should try to verify the running temp with another source. There have been many threads here about aftermarket sending units and most do not read accurately, They read on the high side.
 

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One way to check the accuracy is to temporarily hook up an after market gage to the sender and see what it shows when engine is at operating temp. Re-hook up the dash gage and see what it shows.

Bruce beat me to it--LOL
 

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In my 56 I run a SW mech gauge in the head and stock in the intake and they read very consistant. Now here is the funny part I am a cheapskate and used a used sender from an early 70s chevy parts truck. It works so well I would do it again. I completely agree with the post on midpoint being too high. Mine reads 1/4-1/3 in normal driving.
 

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In my 57 I have the original electrical temperature gauge in the dash with its sending unit in the front of the intake and an aftermarket mechanical gauge under the dash with its capillary tube in the side of the driver’s side head above plugs 1 and 3, late model heads.

With a 180° Robertshaw thermostat my original electrical temp gauge reads just barely past top dead center and the mechanical gauge read just below 190° so I tend to believe that top dead center of the original gauges were meant to indicate 180° or normal operating temperature since they had 180° thermostats.
 

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Discussion Starter · #7 ·
So, since it is apparently reading a little high what would be the progression to find out if it is a mechanical problem with the engine or if it is a problem with the gauge/temp sending unit... any suggestions or steps would be greatly appreciated.
Thanks,
Jeff
 

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any suggestions or steps
Flush the radiator, see how much clean water comes out, what size thermostate do you have usually a 160 is fitted.

What type of fanblade are you running if original some members either add a shroud or electric fans.
 

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You could also use an IR gun and "shoot" the temps in the top radiator hose, top/center/bottom of the radiator, etc.

Chuck
 

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Discussion Starter · #10 ·
Temps Ok??

Sorry for my ignorance but I am not to experienced at this restoration process.
I did get temps using an IR gun, I took the temps both cold and at operating temps.
Are these temps out of line or within proper operating temperature?

cold oper. temp
Top of Radiator 82 178
Middle Radiator 83 156
Bottom of Rad. 84 151
Middle of Rad. Hose 84 148
Thermostat Housing 85 154
Engine block spark 3 86 195
Temp sending unit 86 202

Any suggestions would be greatly appreciated.
Thanks
Jeff
 

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most of the available temp senders are not calibrated for the tri-five gauges. I bought a used original sender when I needed one for my 60 Corvette.

If your IR gun has read the temp at the top tank of the radiator at 178 after having ran the motor until it is at the normal operating temp, and your gauge is reading consistently at the same spot than I would just consider that spot to indicate my normal operating range and be done with it.

Don
 

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Discussion Starter · #12 ·
Thanks Don...
Yes, the temp gauge never went much higher than what I had seen before... it did go lower at times but mostly within a few degree range.
Thanks to all the Tri-Fivers for your help....:congrats:
Jeff
 

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most of the available temp senders are not calibrated for the tri-five gauges. I bought a used original sender when I needed one for my 60 Corvette.

If your IR gun has read the temp at the top tank of the radiator at 178 after having ran the motor until it is at the normal operating temp, and your gauge is reading consistently at the same spot than I would just consider that spot to indicate my normal operating range and be done with it.

Don
Yep. Me too. :D

Chuck
 
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