Will the real temperature reading please stand up....
Thread Starter
Instructor
Joined: Dec 2002
Posts: 174
Likes: 1
From: brandon florida
Will the real temperature reading please stand up....
1972 Stingray
I recently purchased a mechanical Temperature Gauge and
installed it due to my concern with the vette running
hot. I also installed an electric fan to help aid with
the cooling my question/concern is this:
I installed the the mechanical sending unit in the
intake next to the thermostat housing (typical
installation point) where as the stock electrical
gauge sending unit is in the left head, i am noticing
a 30 degree temperature difference between the gauges.
The mechanical gauge is reading cooler than the
electrical gauge, could this be because the electrical gauge
sending unit is being influenced by the heat being generated
by the headers? Which gauge should be trusted?
Let me know your thoughts.
Thanks
I recently purchased a mechanical Temperature Gauge and
installed it due to my concern with the vette running
hot. I also installed an electric fan to help aid with
the cooling my question/concern is this:
I installed the the mechanical sending unit in the
intake next to the thermostat housing (typical
installation point) where as the stock electrical
gauge sending unit is in the left head, i am noticing
a 30 degree temperature difference between the gauges.
The mechanical gauge is reading cooler than the
electrical gauge, could this be because the electrical gauge
sending unit is being influenced by the heat being generated
by the headers? Which gauge should be trusted?
Let me know your thoughts.
Thanks
Le Mans Master
Joined: Jan 2003
Posts: 6,575
Likes: 1
From: Tuttle OK
Cruise-In VIII Veteran
Sometimes, when you do two modifications at once it is difficult to determine which one or if it was both that caused the resulting change.
Since you added an electric fan as well as moved and changed the tempurature guage, I would probably start by reconnecting the electiical guage (if it was still in place) and see if that read the same.
Start with the easy stuff...that's my motto...mainly 'cause I'm lazy..
Since you added an electric fan as well as moved and changed the tempurature guage, I would probably start by reconnecting the electiical guage (if it was still in place) and see if that read the same.
Start with the easy stuff...that's my motto...mainly 'cause I'm lazy..
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 87
From: State of Confusion
I bought my Z28 brand-new in Oct '78, and that electric gauge never wavered from '160*'.....
In '90, I began seriously drag-racing it, and installed a mechanical AUTOMETER gauge into the intake manifold, for closely monitoring water temp between rounds/as I staged.
That OEM gauge would still read nothing but '160*', while the mechanical gauge would vary from 220* thru the traps, down to 130* between rounds.
Probably nothing to worry about, other than 'junk' OEM gauges....
In '90, I began seriously drag-racing it, and installed a mechanical AUTOMETER gauge into the intake manifold, for closely monitoring water temp between rounds/as I staged.
That OEM gauge would still read nothing but '160*', while the mechanical gauge would vary from 220* thru the traps, down to 130* between rounds.
Probably nothing to worry about, other than 'junk' OEM gauges....
Pro
Joined: Jul 2002
Posts: 723
Likes: 0
From: North Port, FL
You could get a fairly good reference point / calibration on both gages by placing the sending units in a pan of boiling water. They shoud read 212. I checked mine this way by using a propane torch to heat the water.
Melting Slicks
Joined: May 2002
Posts: 2,508
Likes: 0
From: Wisconsin
I once thought that my stock electrical gauge was wrong. I said about 160 and I could never get it more. I replaced the thermostat, no change. I installed an electric fan and put it's thermostatic switch in the intake manifold next to the thermostat housing. It is supposed to make the fan come on at 190 degrees. While having the car idle for a while in the garage the fan kicked on. I looked at the gauge, 190 degrees. I was shocked that they were so close.
Safety Car
Joined: Jul 2002
Posts: 4,269
Likes: 3
From: St. Charles IL
Cruise-In 5-6-7-8-9-11-12 Veteran
A CI-6 Car Show Winner
The OEM gauges are a crap shoot at best, but at least they give an indication of "normal" and some idea if things are not in the normal range. Like someone else mentioned, trying both gauges in the same location will give a better comparison reading then 2 different locations. You could always try to get the coolant plug out of the opposite head and install the second gauge there as well.
Le Mans Master
Joined: Apr 2001
Posts: 5,941
Likes: 281
From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
Some temperature senders are not the greatest. I purchased a sender for my car since I figured it would be best to replace the sender when I swapped in the zz4. I found out that the new sender from NAPA was reading 50-60 degrees hotter than the car really was. I eventually swapped back in the old sender and everything is fine. I would suggest like someone else mentioned testing the guage in water cause there is a good chance it could be off.
Racer
Joined: Jan 2004
Posts: 273
Likes: 0
Hmmmm, same situation exactly. Just replaced my heads, figured I should replace the sender as well (Napa also) They swear I have the right part but it reads 230 and I always ran at 180. Buddy (mechanic) has one of those heat guns, man, what a great tool and I verified there was no new existimg temp problem. Napa swears it is the correct part number but I think it may be a glutch on their side or the sender is just bad. They have another for me which I am going to try.
-Andre
-Andre
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Drifting
Joined: Feb 2003
Posts: 1,461
Likes: 2
From: Allen TX
I read a while back on this forum that the temperature senders you get from general parts stores like Napa and Autozone arent calibrated correctly for our gauges or something to that extent. So you wont get the correct reading. There was one website that offered the senders calibrated correctly, let me see if I can find it.
Le Mans Master
Joined: Feb 1999
Posts: 6,807
Likes: 0
From: Hoosier
Cruise-In III Veteran
I believe that it's "LectricLimited" that claims the correct senders for stock gages.
I had trouble getting my Spal fans to trigger on and off at 205-185. I foiund two things.
1-the sender manufacturers say the senders are +/- 10 degrees.
2-headers do influence the sender
My Autometer water temp gauge is in the left head. Autometer sent me a new electric sender (free of charge) when I proved inaccuracy.
I went through 4 fan senders and am using the intake manifold port to get my 205 on and 185 off results. And the water temp gauge matches the on-off of the fan sender.
I had trouble getting my Spal fans to trigger on and off at 205-185. I foiund two things.
1-the sender manufacturers say the senders are +/- 10 degrees.
2-headers do influence the sender
My Autometer water temp gauge is in the left head. Autometer sent me a new electric sender (free of charge) when I proved inaccuracy.
I went through 4 fan senders and am using the intake manifold port to get my 205 on and 185 off results. And the water temp gauge matches the on-off of the fan sender.
Racer
Joined: Jan 2004
Posts: 273
Likes: 0
I have a real cheapy fan I got from schucks mounted as a pusher just to help on really hot days. Actually works very well and it has an adjustable "POT" on the sensor so I can just dial it in wherever desired. It actually worked so well I now have it switched as the primary instead so as the noisy clutch fan will not engage unless the $29.99 unit fails.
Napa swears it is the correct part and that the sender they gave me must simply be defective. I will give it another shot and if the same result persists I will follow your guidance. Unforunately I had the previous sender in a manifold I recently sold and as such no longer have it. I recall it came from either the Napa or Schucks very near my home and worked far more accurately.
Thanks!
Napa swears it is the correct part and that the sender they gave me must simply be defective. I will give it another shot and if the same result persists I will follow your guidance. Unforunately I had the previous sender in a manifold I recently sold and as such no longer have it. I recall it came from either the Napa or Schucks very near my home and worked far more accurately.
Thanks!
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Even New AC delco senders are wrong. Common problem. www.lectriclimited.com has the only accurate one
Instructor
Joined: Jun 2003
Posts: 187
Likes: 0
From: Jesup Georgia
Reply to Temp thread
Originally Posted by Larry B.
Even New AC delco senders are wrong. Common problem. www.lectriclimited.com has the only accurate one
