I am new to the Corvette world finally getting my dream car...1976 L82 Corvette T-Top. The car came with some required maintenance. My Water Temp Gauge needle was pointed far left indicating no power. I opened the hood and found the wirer to the sensor was off. I attached the wire back to the sensor. Upon turning the ignition on (cold motor) the gauge immediately jumped to 200 degrees and began to climb exceeding 280 degrees within 2 minutes. There were no visible signs of the engine being overheated. I then decided it must be a bad sensor and the previous owner just disconnected the wire. I ordered a new sensor and watched YouTube videos. The part I received and the YouTube videos all said that I would need a 15/16 ratchet to take out the old sensor and put in the new. I located the old sensor on the block between the two forward spark plugs and went to remove it...just like in the videos. First thing I noticed is that the old sensor I removed has a 13/16 head on it. Once removed, and yes, coolant did come out, it was smaller than the new sensor that came to me by mail. The part I have seen people replace on YouTube is bigger in diameter than what I removed from the engine block. I have seen on the videos people referring to a water temp sensor and a coolant sensor...is there a difference? Why is the sensor that I removed smaller than what was recommended via the parts store and on Youtube videos for a 1976 L82 Corvette? Thank you for any help/input.

 

A different manufacturer made it. what matters is whether it's calibrated correctly. not it's outside dimensions.

 

Thank you.

 

Since you didn't mention where you bought it and what the part number is nobody can check if you received the correct sensor.

 

Excellent catch and an oversight on my part...I have re-ordered the part thinking the old one wasn't correct. I ordered from CARiD.com. The part is as follows:

Lectric Limited - Engine Coolant Temperature Sending Unit; 1/2 x 14 N.P.T.F.; SKU 1155310857; Part # 06490453

Thank you.

 

That should be the correct one
https://www.lectriclimited.com/tempe...ng-unit-115879

 

Why not ohm it out with a VOM and check the reading with the temperature/ohm chart? (google it).

I would do that on a new one anyway ...in the case you get a bad one out of the box you can take it back before wasting time.

 

Thank you

 

Excellent advice! It’s ironic I found this thread. I just went through this and finished yesterday.

Replacing a temp sender can be a very difficult thing to do. Not so much the actual changing of the sensor, but finding the right one. Because you need to drain coolant each time you swap out a sensor, you don’t want to do it more than once. With some GOOGLE research, you can likely find the resistance curve data for your gauge. I found it for mine with ease. You need to have a sensor that’s matched to the gauge.

I just finished installing a matched sensor in my ‘72 L48. I went through numerous sensors before getting a known original/correct (used) AC Delco unit from a vendor I use in California. He seems to have everything I ever need.

Because I don’t know if he wants to be public or not, I don’t want to post his contact information but if you PM me, and promise not to post it, I’ll share it with you.

Hope this helps
Don

 

That part came in and I removed the sensor from between the #1 and #3 spark plug. What came out is on the left. The part we thought would fit is on the right. Size and threads are different. I have checked the engine block and the numbers match. Any guess as to what is going on?

 

The one you pulled out is 3/8 pipe thread. The new one is 1/2 pipe thread. Usually the 3/8 threaded ones were for cars that had a temperature light. The 1/2 ones for temp. Gauge. I know Wilcox corvette has the correct one that they machine down to 3/8 thread but I think they are out of stock for now.
Some one may have replaced the heads at some point in its past and that’s why it has smaller threads. The one you pulled out looks like the one I have controlling my electric fans. It’s an aftermarket preset on/off switch. May be why it doesn’t work with the gauge.

 

As a newcomer to buying parts for your 76 Corvette, you should look first to one of the CF contributing C3 Corvette parts vendors. It's part of their business model to know all the differences between different C3 Corvette model years.

Wilcox
Paragon
Zip
Top Flight Automotive aka Corvette America
Corvette Central

For websites use Google or look in the CF MarketPlace home page tab.
There's other good sources that are more specialized. LectricLimited and M&H for wire harnesses.

 

I want to thank everyone for their inputs. I was able to find an adaptor that allowed me to use the correct Water Temperature sensor. We placed the adaptor onto the sensor with oil in the gap and then screwed the adaptor into the head. Problem solved.

 

Good to hear. Does the gauge read accurately, meaning have you checked to ensure the gauge reading is confirmed with a pyrometer?

 

Thank you for updating with the resolution! Doing that may help dozens of folks who never post their questions.