1941 Temperature sending unit

[Doug L]

Does this unit work on voltage or resistance.Do I need a 6 volt unit or can I put in a 12 volt unit? And for that matter where can I buy any unit?

Thanks in advance.

Doug Lemon

[Warren Rauch #4286]

 First an explaination of how it works.(See National Data 1941) Basicly there are two electromagnets at right angles in the dash unit , a small permenant magnet on the needle is attracted to them. One holds the needle at cold when the ignition switch is on. The other magnets current is controlled by the engine unit as the temp in the engine rises the resistance drops from (Echlin #'s)46 ohms to 38 ohms (at 220 degrees) this causes the needle to move and reflect the temperature.
The part you need for the engine unit is 1510774 , after WWII it was changed to 1511734, by 1954 (for 6 volt models) it was changed to 1512015. The ohm numbers are different for 12 volt units so they will not work without a recalibration of the dash unit. An old Echlin (NAPA) book lists part# TS-6162 as a replacement. (1/2"pipe thread, 38-46 ohms at 220F) The rating is at 220F because the system is pressurized. Warren

[David King (kz78hy)]

A quick search found this vendor, might try them.

http://collectorsautosupply.com/query.asp?make=CADILLAC&year=0&section=GAUGES

David

[TonyZappone #2624]

I came across a bag of these that I bought for my '41that did not work.  Auto Parts Cellar in New England finally sold me one that moves a little and makes some sense.

[Doug L]

Thank you all for your replies

Doug Lemon

[Don Boshara #594]

I've tried 3 of them in my '40 and none were accurate. Make sure you have a 7# deep cap and if it doesn't boil over, drive it, if it does, you've got a problem.