71 Temp sending unit ... factoryVs "replacement"

[Dale P.]

Since it is well know that ... (I beleive all replacement units give false temp readings) .. where can I get a temp sending unit for my LS5 that is correct .. I understand that the replacement units at room temp read about 400 Ohms and that the correct factory units read about 700 ohms .. I have tried to find them at swap meets and even some local salvage yards .. but since I do not know the correct GM part number (as it was in 71) I am having a tuff time crossing it over to over possible uses .. can anyone help??

[Joe L.]

Re: 71 Temp sending unit ... factoryVs "replacemen

Dale----

The sending unit used on your 1971 was originally a GM #6400759. This is a pin terminal unit. It is VERY difficult to find and expensive if you do (usually in the $100 to $200 range in NOS form). You can also use GM #1513321. This is a button-terminal unit which requires a different connector, but it otherwise perform properly. These are "around" and usually sell in the $50-100 range in NOS form.

There are many good reports of aftermarket sending units which perform satisfactorily with respect to calibration. These are quite inexpensive and that's the route I'd recommend that you follow.

[Dale Pearman]

BEWARE!

The 1513321 temperature sending unit has undergone three revisions without a part number change. In today's NOS form (several are constantly offered for sale on eBay) it will cause readings of 210 and 220 degrees in C1 usage.

Dale.

[Ed Jennings]

Re: 71 Temp sending unit ... factoryVs "replacemen

If you are going to use a button style unit, you can get one at Autozone that seems to function well with most Vette gauges. It will be easier for the counter help to locate if you tell them a Wells TU5. Should cost $5.99. They read about 700 ohms at room temp.

[David N.]

Temperature Sending Unit

I recently replaced my original 1969 temperature sending units. After changing them, the gauge temperature read extremely low. With the 700 ohm information, I checked my new senders and found them much lower in resistance! I also checked the old ones, both right on the money at 700 ohms. THANKS FOR YOUR INDIRECT HELP!!

David Nims #19639