Home page

Topic: Temp sending unit for 75

in Forum: C3 Cooling and Heating Systems


Already a Member? Click Here to Login
Not yet a Member? Click Here to Register for Free!
Temp sending unit for 75 (1/11)
 7/10/18 10:08pm
BillHanna
Standard Member
Send Private Message

Cana, VA - USA

Vette(s):
1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning


Joined: 7/3/2016
Posts: 222

The temperature gauge in my 75 stays very low.  I had replaced the sending unit last year, but it seems there are a lot of ones to choose from -- not sure if the one I have is correct (I got it at a local parts house, so who knows. . .).   I have a second mechanical one under the hood which works correctly,  so I know the water does heat to 180 okay.

I shorted the wire on the sending unit to ground but the gauge only went to a bit below 220 -- I would have thought it should have pegged.

I hate to buy another sending unit not knowing if that is the whole issue (The only one I found specifically listed for a 75 was from Wilcox for $25.00, but they want another $25.00 for shipping!)

Any ideas?




______________

 

  
  
Our Sponsors help support C3VR
Re: Temp sending unit for 75 (2/11)
 7/11/18 6:48am
manchestersharkLifetime Member
Lifetime Member
Send Private Message

Equinunk, PA - USA

Vette(s):
1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 2047

Some of the parts stores products are made in R.O.C. They are junk! I had an issue with brake light switches on my 72'. Used parts house products. Could not get one that worked. Remember, that electronics are not returnable! After the third one that would not work, I bought a GM one at a local dealer. Less cost than the three parts house products that didn't work, and it worked fine, still does. Sometimes GM parts are cheaper in the long run than parts house products. Especially if you have to drain water to replace a part. The General has good well made parts. The first time around purchase MAY be the least expensive in the end even if initially more than parts house.
Re: Temp sending unit for 75 (3/11)
 7/11/18 10:17am
F4Gary
Standard Member
Send Private Message

Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air.


Joined: 8/26/2006
Posts: 1028

Lectric Limited seems to have good temp senders.

______________

Re: Temp sending unit for 75 (4/11)
 7/11/18 3:00pm
BillHanna
Standard Member
Send Private Message

Cana, VA - USA

Vette(s):
1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning


Joined: 7/3/2016
Posts: 222

F4Gary said: Lectric Limited seems to have good temp senders.

Thanks; I ordered one from them -- shipping was only $5.95. . .



______________

 

  
  
Re: Temp sending unit for 75 (5/11)
 7/18/18 1:36pm
BillHanna
Standard Member
Send Private Message

Cana, VA - USA

Vette(s):
1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning


Joined: 7/3/2016
Posts: 222

I got the new temp. sending unit from Leteric and put it in.  The gauge still reads way too low (around 110).  When I ground the wire to the sending unit, the gauge does go to 220.  Any idea what is going on???



______________

 

  
  
Re: Temp sending unit for 75 (6/11)
 7/18/18 8:33pm
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19797

If the temp gauge is not pegging out when you ground the sender wire, the problem is either the gauge itself, or the wire. Might be a corroded connection at the firewall pass-thru(fuse box), or on the circuit board behind the cluster.

______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Temp sending unit for 75 (7/11)
 7/19/18 12:20pm
F4Gary
Standard Member
Send Private Message

Grapevine, TX - USA

Vette(s):
1972 LT-1 convertible with factory air.


Joined: 8/26/2006
Posts: 1028

Did you put teflon tape on the threads of the sending unit?  Not supposed to.

______________

Re: Temp sending unit for 75 (8/11)
 7/20/18 7:34pm
BillHanna
Standard Member
Send Private Message

Cana, VA - USA

Vette(s):
1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning


Joined: 7/3/2016
Posts: 222

F4Gary said: Did you put teflon tape on the threads of the sending unit?  Not supposed to.

Hmmm, I did put teflon tape on it.  I'll correct that this weekend.
It does seem, though, that most of the tape gets rubbed off when threading it in tight.
Thanks for the heads-up, and for all of the rest of the responses.



______________

 

  
  
Re: Temp sending unit for 75 (9/11)
 7/21/18 8:08am
manchestersharkLifetime Member
Lifetime Member
Send Private Message

Equinunk, PA - USA

Vette(s):
1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.


Joined: 10/31/2007
Posts: 2047

I have used the teflon on many occasions, never seemed to bother.
Re: Temp sending unit for 75 (10/11)
 7/22/18 8:37am
Adams' AppleLifetime Member
Lifetime Member
Moderator
Send Private Message

Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 19797

If you ground the wire for the gauge and the gauge is not pegging, then it makes no difference if there is tape/sealer on the sending unit...at that point the sender is out of the equation.
Granted, using sealer/teflon on a sending unit CAN create false gauge readings, from what I am reading here, this is not the case. From what I read, the gauge is not pegging all the way HOT with the sender wire grounded...and it should be pegging. 
Unless I am reading it wrong....wouldn't be the first time. Embarrassed


______________
Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Re: Temp sending unit for 75 (11/11)
 7/25/18 7:42am
BillHanna
Standard Member
Send Private Message

Cana, VA - USA

Vette(s):
1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning


Joined: 7/3/2016
Posts: 222

Well, I'm planning on removing the heating system this Winter to see if I can get the heat right (off in Summer, on in WInter. . .), so at that time I'll have the center console out and I can test the gauge and wiring then.

Does anyone know what the maximum and minimum resistance (or voltage) should be for the gauge?  One thing I can test is the resistance of the shunt across the gauge.



______________

 

  
  
Our Sponsors help support C3VR