temperature sending units

[67Vette427]

My temp gauge seems to run a bit on the warm side but when I check the engine temp with a separate meter the temp is around 180 at the head/block area. I installed a new sender when I built the motor but maybe I should try another one. Do they make sender's for a varied temp? 

[Chryco Psycho]

can`t hurt to try a different sender , pay a few $$ extra if possible ity may be worth it for accuracy , their has to be a few companies making them , I know Standard has them

[BS23VOB_FJ5_Faker]

I have 2 different spares which I tried, and were reading a little low for me.  I would be happy to send them to you to try out if you send back the two you don't use.  One was from NAPA, and the other was from a Chrysler dealer.  The one from the Chrysler dealer read the lowest for me.

[miketyler]

make sure your guage is grounded well. I added a second electric gauge to my setup and hooked it up to what looked like a good ground source. Last weekend the 2nd gauge was running 10-15* hotter than the rallye guage and the needle would increase slightly with the gas pedal. I reset the ground and it is rock solid again. The OEM guage might be subject to the same issue if ground is not 100%   

[67Vette427]

Thanks for the good suggestions and the offer faker. The switchs aren't that much at Napa. I'll pick one up. Its too much trouble and expense for you considering the cost of mailing. Thanks though very generous of you.

[BS23VOB_FJ5_Faker]

No problem.  When I was trying to dial in my gauges, I tested the three with an ohm meter while putting them in hot water and got the following results:

Temp of water  (F)   81          160          210

Mopar                    222.3      74.2         38
Autozone               172.5       48,4         31.7
NAPA                    166          46.3         30.8


If yours is reading high, you are going to want the one with the greatest resistance to lower the sweep of the needle.  The Mopar one had significantly more resistance than the other two, so it made my gauge read too low for my liking, since my gauge reads a little too low to begin with. 

Since your gauge seems to read a little high, the Mopar sender is probably the best bet for you. 

What brand is the one you put in?  Since the old wiring in our cars tends to have more resistance with age, most of us are probably better off with the lower resistance ones.

[67Vette427]

You know I put it in about a year ago and I think it was from Napa but I can't remember for sure. The Mopar switch sounds about right though. Where did you get it from ? Good info. on the tests too. I was going to do that with mine. I just went through all this a couple weeks ago on a 65 Imperial convertible I have.

[BS23VOB_FJ5_Faker]

I got it right from my local Chrysler dealer.  It was about $30, versus the $5 for the NAPA ones --but I figured it was well worth it if my gauge reads more accurately.  Unfortunately, it was worse than the cheap ones in my particular application.

BTW, I assume you had similar issues with your Vette - it took me seven or eight reproduction sending units to find one that worked right for my Midyear gauges.  The readings for those sending units were all over the place even from the same manufacturer.

Since your gauge reads high, you could always resort to putting a resistor inline with the sending wire.

If you do measure the resistance of the sender you have, I would be interested in buying it from you if it measures out lower than the ones I have.  My gauge still reads a little lower than it should.

[67Vette427]

I'll measure it out once I get another.

With the Vette I believe its the original sender. The car only has 46k original miles and its an all #car. I have the original BB on a stand and I built the 502 for it back in 2002 and swapped the senders from the 427.

Maybe if I still have probelms I'll swap you one for the Mopar one and pay the difference in price.

[67Vette427]

I measured the new one I got from pepboys and it came out pretty close as the Napa.

Napa

cold 71* 255 ohms                 warm 180*    33 ohms

Pepboys

cold 71* 200 ohms                 warm 180*     31 ohms