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my wifes 67 gt (with decore int ) has always run toward the hot side , even with all the right $tuff---but it's never puked coolant---i've changed senders and gauges but all are the same----i called green sales and ordered a nos sender for the car---pricy--yes---but it dropped the top end of the scale to where it should be---about straight up
doctordesoto
 

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That much difference between a factory sender and a new replacement? Wow, What engine is in her car?
 

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I must agree, I bought every brand of repro temp sender with all reading HOT. I eventually found an antique auto parts dealer locally and bought a NOS Autolite one that I trust reading about middle of the gauge. 4 times the cost but correct.
 

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So what is the correct resistance range on them then...? That should be what really maintains the guage in the right position.....I don't see any reference to it on the manual and it would help a ton to know?
 

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Mine has always run on the hot side. Didn't read at all when I bought it but put in an after market from one of the major players in Mustang/Cougar parts. Running a 20" radiator in a 302 J code with A.C. Gauge gets all the way to just below red with A.C. and a red light. Beginning to wonder if maybe replacing with an old stock sending unit might give me different info. I may be another to pay the price for a "proper" sending unit. Would be cheaper than the radiator and fans set-up that I have been contemplating....
 

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So what is the correct resistance range on them then...? That should be what really maintains the guage in the right position.....I don't see any reference to it on the manual and it would help a ton to know?
This what I found.
About 17 ohms at full hot and about 75 ohms fully cold. 17 ohms would have the guage pegged all the way up. 75 ohms at the other end of the scale.
Charlie
 

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I think I need an N.O.S. temp. sending unit. Five minutes into driving and my needle is completely buried on the gauge.
 

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I think I need an N.O.S. temp. sending unit. Five minutes into driving and my needle is completely buried on the gauge.
If it gets that hot that quickly you ought to check to see if your thermostat is staying closed.
 

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I have a new restrictor plate and thermostat coming from W.C.C.C. I have a new thermostat in it and it opened and closed fine before I put it in.
 

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Have to concur with others here. I have a brand new setup in my 68, 302 crate engine, aluminum radiator, everything is new in there. Within five minutes the gauge was reading all the way to the right. Even a freeway speeds it was over 3/4 the way over. Found a Motorcraft SW-552 temp sender and VOILA, barely reads 1/4 the way over now, idling about 1/3 over. How or why such a simple little part makes this difference, I don't know. But I am relieved to know that now when it reads hot, I really do have something going on.
 

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I have a 67 with 289 that i bought a couple of years ago. Temp sender was broken when i bought it so i just went to the local parts dealer and got a new sender. Ever since its read at least 3/4 high all the time...just above the P. Plus on the hot days of the summer it does vent some coolant. When you say you found a Motorcraft sender...where did you get it? Sounds like it could sovle some of my problems too.
 

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I found the same thing. I recently bought a repro sender from West Coast Classic Cougar. It reads much higher on the guage compared to an NOS sender. Who ever is making them is not doing it right.



my wifes 67 gt (with decore int ) has always run toward the hot side , even with all the right $tuff---but it's never puked coolant---i've changed senders and gauges but all are the same----i called green sales and ordered a nos sender for the car---pricy--yes---but it dropped the top end of the scale to where it should be---about straight up
doctordesoto
 

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You may be able to make them work though - may need to add a resistor to bring it into the correct range like Charlie point out.....not the best thing - but a possible work around.
 

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Bought one from NAPA and NPD, both read 3/4 on a cool normal driving day with no air. Ordered an NOS one from Green Sales ($$$) and its right in the middle with air on and stop and go driving.
 

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I have a 67 with 289 that i bought a couple of years ago. Temp sender was broken when i bought it so i just went to the local parts dealer and got a new sender. Ever since its read at least 3/4 high all the time...just above the P. Plus on the hot days of the summer it does vent some coolant. When you say you found a Motorcraft sender...where did you get it? Sounds like it could sovle some of my problems too.
I found it at Cascade Classics. I think John said it was his last one in stock however.
 

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I have the same symptoms with the temp sender I installed a few months ago. Reads around 3/4 hot pretty much all the time after it's warmed up. Except, after I drive around a while with it warm, and then park and let it sit, when I come back and turn it on it's all the way in the red hot, but drops down right away after a few seconds.

I don't plan to do anything. Having 3/4 temp be normal works fine for me, I know that's what's normal and I know if it moves up into the red while I'm driving then something's up.

Same behavior both before and after I replaced the thermostat and water outlet a month or so ago.
 
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