So my '73 vette runs fine (no overheating) but the guage only reads 150 degrees when fully warmed up. I know that is has the newer style 280 degree temp guage (1975-1976) VS the correct 250 degree temp guage (1972-1974) that is supposed to come with the car.

Would that make a difference? I know that the temp sending unit says made in usa on it, but not sure if it is reading right.

Any tips on how to figure out which part is making the gauge read only 150?

Will changing to the correct gauge change anything?

 

Your gauge is only doing what the sending unit is "telling it". SO also NOT having any thread tape on the sending unit is wise. Just get it tight and it should not leak....because the thread tape can effect the completion of ground to the sending unit.

DUB

 

is this something it has always done or a new problem,? according to this site the sender unit would be the same part number for 73 and 75. Are you sure the thermostat isnt stuck open.

http://www.lectriclimited.com/shoppi...p?id=871365024

 

This is something the car has always done. The t-stat is less then two years old ( I installed it my self) and works just fine.
The temp sending unit in my engine is orginal to the engine, but since the engine is NOM, who knows what year it is from.

I will change out the gauge to the right one (1972-1974) and see if that makes any difference at all.

 

Honestly...I have used the lectric limited senders with good results. But it has EVERYTHING to do with quality control being REALLY TIGHT.

The oil inside and the spring have to be correct. They can be a bit touchy. Buying one from "whoever" else can lead to a major cluster.

DUB

 

Ill keep them in mind of the gauge does not fix the issue

 

Chstitans- The issue is the dash unit. The inputs are different for the two gauges..

We are working on a gauge resistor that will allow you to make the gauge match the sender and should be finished with it very soon.

Willcox

 

Its easier to change the sender than the gauge, is it not possible to fit a sender for a 75 - 76?

 

That is very true, but since I want to have the correct gauge, then that is what I will fix. Plus I already bought one from Willcox a while ago

 

I am ALL IN on that. Anything that saves me the time to send out a gauge to have it "dialed-in"...I am all for.

I know this has to be tough to do...because the new sender I bought due to the thread size in the cylinder head was different (smaller)...that when I installed it...the sender worked but was about 100 degrees off.

DUB

 

We are close Dub..

I've tested the last proto.. and the boards are here now.. Honest truth, we don't have time to build them just yet. The other major vendors are killing us for the other parts... (tach boards, Low fuel warning modules, delay timers, and other electrical stuff) We're building them as fast as humanly possible right now. I will not send these parts oversea's.. We should be ready to finish them up in a week or so.

I'll let you in on something else.. I too was told a certain brand of senders had the oil in them... they don't. I cut three different senders apart to see... none had oil in them.

The oil isn't really the issue anyway.. The issue is the thermister inside the sender being wrong. The oil in the senders serves two purposes.... 1) It allows for a constant heat up of the sender dispersing the heat through the entire cavity.
2) It keeps the sender spring from corroding where it meets the top button contact.

That oil should you cut one open... is more than likely pyranol which contains pcb's... not something to play around with either..

In the thread you'll actually see a picture of a corroded spring that caused a failure in the sender. So what happens.. over time the oil leaks out of the sender. When it gets below the spring to top contact point it will corrode and when this happens the sender fails. http://forums.corvetteforum.com/c3-g...-you-dare.html

But... there is a new brand of senders that have recently hit the market.. I have all of them on order and they should arrive soon.. I'll be boil testing these, charting them and yes... cutting the tops out to inspect when they arrive. I'll probably video this when I do it.

Willcox

 

RIGHT ON!!!!! What I LOVE about all this is all the "stuff" that has to be in place to get something out on the market that will work.

It seems to me that each time I have to buy a part I shutter in fear that some DUMBA$$ "bean counter" had to get their hands in how "stuff" needs to be made so they can make more money selling crap.

I AM NOT WRITING THAT YOU are the mentioned above "bean counter"..AT ALL.

Best of success in your conquest.

DUB

 

UPDATE!
So I installed the new gauge, leaving out the 90 ohm resistor as per the included directions, and the gauge reads the same as the old one, right around 150 degrees. Does this mean that my problem lies with the sending unit?? I'm confused here seeing that both the 72-74 gauge and the 75-76 show the same temp with the same sender. Were they not supposed to have different senders?
Willcox, do the senders from lectric limited work and make the gauges read right?

 

My gauge never worked correctly in my '73 until I got a new sending unit from Lectric. I highly recommend their products.

 

That's what I'd change next.

 

Why? It is only a few years old and the top rad hose gets hot. I know for a fact it works

 

It's cheap and easy to change and you have the correct sender and gauge so what else could it be? They can fail is way less than two years.

I have a Wells TU5 sender and it works properly on my 74, what sender do you have?

 

I dont know if I have the correct sender, all I know about mine is that is says made in usa on it. My next step will be getting a sender from lectric limited and seeing if that fixes the problem.

 

Bought the sender from Lectric Limited. Hopefully it works!