El Camino Central Forum banner
1 - 20 of 22 Posts

· Past Texas Director
Joined
·
6,191 Posts
Discussion Starter · #1 ·
My temperature gauge stopped working recently, so I replaced what I THOUGHT was the temp sensor. It's on top of my thermostat housing. It didn't make any difference-still no working temp gauge.



So, today I bought a new temperature gauge, and as I was following the wire from the top of my thermostat, I happened to notice another brass looking bolt with yet another sensor attached near my driver side headers-on the block. It had the same end as the NEW gauge I just bought.



I got it figured out, and Jim connected the new gauge (sensor end) into a new fitting in the side of my block, and voila, my new temp gauge works just fine!

My question is...what the heck is that other thing plugged in to the top of my thermostat housing? Also, my original dash temp gauge has never worked, I've only had an after market one since I've owned the car. :dontknow:
 

· Registered
Joined
·
3,040 Posts
The sending unit on your intake manifold near the water inlet is for the computer.On older model small block Chevys it was for your temp. gauge.The S. unit on the driver side near front of the head is for your temp. gauge.At least that is it for my 86.
 

· Past Texas Director
Joined
·
6,191 Posts
Discussion Starter · #5 ·
The '78 model year doesn't have the ECM CCC system. Maybe a different engine or parts are in there ??
I'm hoping Fixitman-Roy will see this and be able to let me know what it is. He put this engine in just a few months ago.

Yes, I figured that much out--just am questioning what the one on top of the thermosat is for. I don't want to take it off incase it's something I actually NEED. :dontknow:

Thanks for your input you guys! :beer:
 

· Past Texas Director
Joined
·
6,191 Posts
Discussion Starter · #6 ·
The sending unit on your intake manifold near the water inlet is for the computer.On older model small block Chevys it was for your temp. gauge.The S. unit on the driver side near front of the head is for your temp. gauge.At least that is it for my 86.
I don't think my motor has any of the computer stuff. :dontknow:
 

· Premium Member
Joined
·
1,134 Posts
Hi Guys,
I'm not trying to hijack the thread but this brings two questions to mind.
First my motor(400 out of a 78 PU) has the sensor shown in the picture, its currently not connected. I have an after market water temp gauge that is connected to a sending unit that I installed in the intake manifold. Would the factory sending unit(down on the head) work with the aftermarket gauge?
Given the stock sensor's location wouldn't the heat from the headers/exhaust manifold throw it off a bit?
Ang.
 

· Registered
Joined
·
1,348 Posts
The sender on the side has its sensor in the water, so it won't be affected by the headers. If you use the standard water outlet (or the usual chrome replacement), it may not clear a temperature sender in the port on the manifold. I just discovered that this week when I moved the sender up to the manifold, where I prefer to have it. There has long been argument about the best location for the sender. In the manifold, it is sensing the water at its hottest, just before it leaves the engine to go to the radiator.
 

· Past Texas Director
Joined
·
6,191 Posts
Discussion Starter · #13 ·
Terry, one is for the dash temp,thats the one on the thermostat housing, the one down by the headers,is the Manuel temp,the one you had Jim replace . i don't remember your dash one working ..
Thanks Roy! You're right, the one in the dash has NEVER worked since I've owned it.
It was making me nuts not knowing for sure WHAT it was for. :You_Rock:
 

· Past Texas Director
Joined
·
6,191 Posts
Discussion Starter · #14 ·
Hi Guys,
I'm not trying to hijack the thread but this brings two questions to mind.
First my motor(400 out of a 78 PU) has the sensor shown in the picture, its currently not connected. I have an after market water temp gauge that is connected to a sending unit that I installed in the intake manifold. Would the factory sending unit(down on the head) work with the aftermarket gauge?
Given the stock sensor's location wouldn't the heat from the headers/exhaust manifold throw it off a bit?
Ang.
YES the factory sending unit (down on the head) WILL work with the aftermarket gauge-that's how mine's hooked up and is working perfectly, and that's how it was working to begin with but the old gauge quit on me. Just make sure to route the new gauge wire/to the sensor, in a manner so it's not going to get fried from the heat off of your headers.
We put loom over the wire-just to protect it a little more, and then zip tied it up to the a/c compressor bracket to be sure it didn't end up touching on my headers.
 

· Registered
Joined
·
2,075 Posts
YES the factory sending unit (down on the head) WILL work with the aftermarket gauge-that's how mine's hooked up and is working perfectly, ...
Be careful with this.
Different manufactures of the gauges and sending units use different values in the resistance
between the gauge and the sending unit.

You just happen to luck out that the aftermarket gauge was close to the factory one in the working ranges of resistance.

Stewart Warner
VDO
Autometer
ETC..

All use different parameters to make their stuff work.
 

· Premium Member
Joined
·
1,324 Posts
Terry, your gauge will work from either place. They may not register exactly the same unless you move the sender from one place to another. Are you using mechanical or electrical temp gauges?? Doesn't really matter which. I have one sender in each place, and get different readings because they are different part numbers (electrical), as I switch the wire from one to the other. In order to get the one I'm using (intake) to register close to IR readings (handheld), I've had to add resistance (resistors) to the wiring to get it to read close. This is the original/dash gauge. I have bought an electrical gauge/sender/wiring (O'Reilly) to use on the head outlet, just haven't taken time to do it. I'll mount that using velcro to do a double check. I have a single row raddy, and will replace with 3 or 4 row for better cooling. Using pusher/puller electric fans.
 

· Past Texas Director
Joined
·
6,191 Posts
Discussion Starter · #18 ·
Be careful with this.
Different manufactures of the gauges and sending units use different values in the resistance
between the gauge and the sending unit.

You just happen to luck out that the aftermarket gauge was close to the factory one in the working ranges of resistance.

Stewart Warner
VDO
Autometer
ETC..

All use different parameters to make their stuff work.
Thank you Bryan for clairifying that! I assumed because THIS one worked, that they all would. :beer:
 

· Registered
Joined
·
9 Posts
I think you solved my problem

I have the same problem with my original gauge that was working and stopped. I did the same thing, bought a new sending unit, installed it in the goose neck. It still doesnt work. :-( I guess, I'll either buy another one and install it in the right place. or move it to the right place. They must be identical.
 
1 - 20 of 22 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top