Hey all so just picked up this beauty I’m curious what the best temp sending unit would be I’m repymine this weekend I do have seatbelt lights apparently some sensors can’t be used if the car has warning light

 

190-195 is a good range. A few things that affect cooling on C3's you should be aware of are:

1) Former dufus owners toss the rotted and brittle foam gasketing which goes around the fan shroud. Then what happens is air gets sucked in around the edges of the shroud and not THROUGH the radiator. They make a foam sealing kit ...and that can make a MAJOR difference. Look and make sure your fan shroud's foam is in place. This is really important.

2) Former dufus owner see's a shiny blue flex fan in the parts store and tosses the original fan. Aftermarket flex fans often work terrible. Plus they have a nasty habit of flying through the hood. If that is the case, go back to the original style fan with a new working fan clutch.

3) Fan clutch stops working.

4) Former owner used 'hard' water in the coolant. Lime/mineralization is going to deposit against the inside of the cooling passages. You can chemically de-lime a radiator with like Ridlime. Always use DeIonized or highly purified water! Or premixed coolant.

5) There's a build-up of bugs/debris between the AC condenser and radiator you can't see...and that's cutting down airflow/heat transfer. Remove radiator and make sure air can go through.

6) Aftermarket thermostat was used which is terrible quality (or installed backwards)

7) Lower radiator hose doesn't have the spring in it....and the hose 'suck-in' under road speeds

8) Water pump impeller is loose ...but works ok when parked....but slips when it gets warm...at roads speeds.

9) A lower air dam helps 'deflect' air "UP" into the radiator.

A lot of ower's so-called "Chronic" cooling problems are just simple things which may be a combination of above...and they blame the Corvette design, or an 'old' radiator. Problem with an Aluminum radiator is you can't hardly keep the coolant's pH within the 'happy' range..and the aluminum will eventually get eaten away... Vs brass which is a noble metal and will last a LONG time.

 

There is no connection between a temperature sensor and a seat belt warning light.
Why are you replacing the temperature sensor?

 

Yes I find the question interesting as well. The temp sending unit, or sensor is for the temp gauge. I haven't found a replacement that actually works correctly. I'm running a original temp sensor for my gauge.
What that has to do with seatbelts I'll never know.

 

Do you have a California spec 1980 with the 305 ci LG4 engine?

If you have more than a single wire going to your carb, you probably have the computer controlled carb (CCC) system, the same as all 81 cars.

Please post some photos of your engine with the air cleaner removed!

 

it appears to be original so I thought a new one may be more accurate?

 

If anything less accurate. Rent an IR gun to check accuracy.

 

Congrats & welcome!!

Do you have reason to suspect the sensor is faulty? Ohm the sensor out with a multi-meter (cool and hot) and cross reference via a resistance/coolant chart (watch a video on how to do it). A lot of new import sensors & stuff is of poor quality. ...unless you have reason to suspect it's faulty.

 

thanks everyone I love this forum it’s definitely helpful

 

no reason just thought it would be an idea but after reading into it only fix with at is broke and my water pump needs more attention now then sensor now

 

@Mark G Do you have a link to such a video? Or, even better, a resistance/temp chart? I spent a lot of time searching for one, and came up short.

The 2 and 3-wire sensors sold for later cars have datasheets readily available. I could find no specification for the older sensors. If, say, Lectric Limited knows what they are doing, I couldn't find where they are sharing the datasheet.