Temp sending unit question:
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Pro
Joined: Nov 2006
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From: Davie FL
Temp sending unit question:
Driving the C2 around in the hot south Florida summer.The AC is on and getting stuck in traffic.Watching the temperature gauge slowly climbing to 230. Shut the AC off, roll down the widows. I get the car to the house and check out the hoses with the IR gun.Top hose showing 190 deg and bottom showing 165. The sending unit is way off.
Any pictures or ideas where you installed a variable resistor for the temperature sending unit ?
Any pictures or ideas where you installed a variable resistor for the temperature sending unit ?
Race Director
Joined: Feb 2007
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From: northern california
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For example, suppose you add series resistance of such a value that 180*F coolant temperature indicates 180*F on the gauge. At coolant temperatures above 180*F, the gauge will read lower than actual coolant temperature, giving you a false sense of security.
Jim
Racer
Joined: Mar 2006
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From: ALLEN Texas
Resistor
Driving the C2 around in the hot south Florida summer.The AC is on and getting stuck in traffic.Watching the temperature gauge slowly climbing to 230. Shut the AC off, roll down the widows. I get the car to the house and check out the hoses with the IR gun.Top hose showing 190 deg and bottom showing 165. The sending unit is way off.
Any pictures or ideas where you installed a variable resistor for the temperature sending unit ?
Any pictures or ideas where you installed a variable resistor for the temperature sending unit ?
180 degrees when the IR gun showed 180. If the gauge gets higher than that by very much (say 200) then I know there is a problem. That's all you can tell with a resistor in line.
Just splice it in where the sending wire goes into the firewall. Use about 30 inch leads so you can get to it and adjust to match the IR gun
reading at the water outlet (while engine is normal operating temp).
Stuff the resistor behind the radio console.
I used a 0-100 ohm resistor from Radio Shack. Get a plastic covered
one that uses a small screw driver to adjust. One with a dial **** can
get bumped and lose the setting.
Ray
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Corvette Central sells an adjustable resistor (30 bucks) that you can install at the gauge on the dash between your wiring and the gauge. It's adjustable so you adjust it to your IR gun. I've installed one in my car and a friends car and they both work perfectly. And yes, it will go above your initial setting you make, so don't worry about false readings. I set mine at approx. 180 and it will climb if it idles in traffic, and I have checked it with the IR gun while it's hot and it gives the same reading as the gauge. My car will stumble when running hot also, and the gauge will verify it.
Race Director
Joined: Feb 2004
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From: CT
The easiest solution is to get another temp gauge and make a take on/take off mount somewhere in the car so you can see it, and, if necessry remove it when you want. The sending unit can either go in the head, or you can get an adapter that goes in a heater or radiator hose. The modern unit will be accurate and you can leave the origninal in the car for the nit pickers.
Burning Brakes
Joined: Dec 2006
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From: St. Charles/Cave Creek IL/AZ
How about just getting the correct sending unit?
I am a simpleton, so I like simple solutions.
I had the same problem so I got a Duralast TU-5 at the AutoZone website and my gauge now reads accurately.
I had the same problem so I got a Duralast TU-5 at the AutoZone website and my gauge now reads accurately.
Melting Slicks
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From: Strongsville, OH
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Dave
Last edited by dkleather; Jun 30, 2010 at 10:50 AM.
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Pro
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From: Davie FL
Sorry Doug, I should have mentioned that this will be the third one that I installed.I just called the local Autozone and they had one Wells TU5 left. Will give it a go this evening.
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Melting Slicks
Joined: Jul 2004
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From: Maryland
The easiest solution is to get an original that is calibrated correctly. Mary Jo sells them.
www.vettegal.com
www.vettegal.com
Drifting
Joined: Apr 2008
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From: Lexington Park Maryland
Driving the C2 around in the hot south Florida summer.The AC is on and getting stuck in traffic.Watching the temperature gauge slowly climbing to 230. Shut the AC off, roll down the widows. I get the car to the house and check out the hoses with the IR gun.Top hose showing 190 deg and bottom showing 165. The sending unit is way off.
Any pictures or ideas where you installed a variable resistor for the temperature sending unit ?
Any pictures or ideas where you installed a variable resistor for the temperature sending unit ?
Team Owner
Joined: Aug 2007
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Army
I've heard that Mary Jo and Dewitt's sell calibrated (but expensive) sending units but folks have had trouble with those too it seems. You can use one of those little plastic rheostats with the screw driver adjustment and once its set dab some nail polish on the adjustment to keep it set...
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Good luck, I tried that one too plus about 9 others and none of them worked correctly. I spent more than enough on those to buy the one from Corvette Central to begin with, but I was trying to get off cheap. Get the one from CC, and it's over.
Burning Brakes
Joined: Dec 2006
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From: St. Charles/Cave Creek IL/AZ
I'm still a simpleton!
Obviously, this is a continuing source of frustration, and I hope everyone will report their results as they experiment with different possible solutions.
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Pro
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From: Davie FL
Well the third one is the charm !! Installed a Wells TU5 and the temp gauge is spot on. Sure is refreshing not having to keep looking at that temp gauge showing faulty readings. Thanks for the tip !
Burning Brakes
Joined: Dec 2006
Posts: 965
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From: St. Charles/Cave Creek IL/AZ
The Corvette Specialties link that Jims66 included above makes a good point.There are probably millions of OK sending units screwed into engines in junkyards all across North America.
If the car or truck had a temp gauge, the sending unit may still be worth a try.
Team Owner
Joined: Oct 2000
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From: Washington Michigan
An original AC #1513321 sender is the best replacement, but you have to dig through 60's junkyard engines to find them. I got lucky with mine - it has a Standard ST-6 sender, and it's right on the money. Photo below shows the AC original on the left, and the Standard ST-6 on the right.
