>From the comments on the net, sever people are replacing the OEM temp
sending unit with a NAPA sending unit. These NAPA temp sending units are
not a "high dollar item" and they can be manufactured by several
different vendors, all of which can cause considerable variation in the
resistance reading of these units. They are not much of an improvement
over the OEM sender if you don't calibrate them before you put them on so
you know what the true temp reading is at the 1/4, 1/2, 3/4, and max
points on your gauge.
It is very easy to calibrate the units, or any other temp gauge. All
you need is a small pan or coffee can, a small heating source (I use a
small single burner camping stove that screws on top of a small propane
canister), and a thermometer that will read up to 250 degrees F( I use my
wife's cooking thermometer that I verify is reading correctly in boiling
water). Place a board across the engine access opening and locate the
heating unit and pan of cooking oil near where the engine sending unit
is mounted( only do this with the air cleaner on the engine and make you
have no gas leaks around the engine). Use a short length of jumper wire
to connect the sending unit terminal to the wire connector going to your
gauge, and another jumper wire to ground the sending unit to your engine.
Using a small wire, hang the sender down into the cooking oil. turn on
your ignition and slowly heat up the oil. Record the thermometer reading
at the 1/4, 1/2, 3/4, and max marks on your dash gauge. You now have
your gauge calibrated. I made a small barograph on a piece of
"sticky-back" paper with a vertical line with four cross marks and I
typed the calibrated temperature values at the 1/4, 1/2, 3/4, and max
marks. I placed this bargraph vertically on the glass in the center of
the gauge cluster where the temp gauge is located (If you have a good
memory you can skip this last task).
Chuck Aulgur
La Mesa CA
GMCWS Tech V. P.
sending unit with a NAPA sending unit. These NAPA temp sending units are
not a "high dollar item" and they can be manufactured by several
different vendors, all of which can cause considerable variation in the
resistance reading of these units. They are not much of an improvement
over the OEM sender if you don't calibrate them before you put them on so
you know what the true temp reading is at the 1/4, 1/2, 3/4, and max
points on your gauge.
It is very easy to calibrate the units, or any other temp gauge. All
you need is a small pan or coffee can, a small heating source (I use a
small single burner camping stove that screws on top of a small propane
canister), and a thermometer that will read up to 250 degrees F( I use my
wife's cooking thermometer that I verify is reading correctly in boiling
water). Place a board across the engine access opening and locate the
heating unit and pan of cooking oil near where the engine sending unit
is mounted( only do this with the air cleaner on the engine and make you
have no gas leaks around the engine). Use a short length of jumper wire
to connect the sending unit terminal to the wire connector going to your
gauge, and another jumper wire to ground the sending unit to your engine.
Using a small wire, hang the sender down into the cooking oil. turn on
your ignition and slowly heat up the oil. Record the thermometer reading
at the 1/4, 1/2, 3/4, and max marks on your dash gauge. You now have
your gauge calibrated. I made a small barograph on a piece of
"sticky-back" paper with a vertical line with four cross marks and I
typed the calibrated temperature values at the 1/4, 1/2, 3/4, and max
marks. I placed this bargraph vertically on the glass in the center of
the gauge cluster where the temp gauge is located (If you have a good
memory you can skip this last task).
Chuck Aulgur
La Mesa CA
GMCWS Tech V. P.
