Temp gauge faulty

[cg124]

I am looking for some help from those of you with greater knowledge and experience than myself.

The temp gauge in my newly acquired car just started going wonky on me. As soon as the car is turned on it jumps right up to 250F. Had it checked out briefly and the guy figured it was the sending unit. The engine is a 302 and the gauge is Smith. Do I have to go to Smith's for the sending unit or would it be somewhat generic and something I could pick up at a local parts store?

Thanks for any and all assistance.

CG
289 street machine

[madmaxx]

The smith sending unit uses a "tube" filled with gas. Call Nisonger or replace gauage with new sending unit.

[Ron61]

If you have a spare gage just disconnect the one in your car and connect the sending unit to the spare gage and see if it does the same thing. Personally I never did like the sending units with the tubes filled with gas for the temp or oil pressure. I went with electric ones on mine and never had any problems at all.

Ron

[CWizard]

CG- If it's a Smith's mechanical temperature gauge, there is no separate, replaceable sending unit. You have to replace the entire gauge assembly. You can get it repaired but the cost of a replacement is usually less than repair plus 2-way shipping. Check with Nisonger or Gauge Guys for details on either option.
Strange failure mode - they usually fail low. Maybe you have an electric Smith's?
Good luck.

[Clois Harlan]

check to see if your gauge is grounded incorrectly. Hopefully, you will find access to the sending unit in the top of your gas tank. Sounds to me like the wires are crossed at the sending unit. Of course you could switch your wires at your gauge to check it too.

[cg124]

Thanks for all the input. It is an electrical gauge and I have been in touch with Nisonger about. The gauge is quite old (early '80's) so I will probably just get a hole new unit (gauge and sender).

Cheers,
CG