Broken line to Oil Temperature Probe, Repairable?

I have a Cessna 172M with o-320-e2d engine.

The metal line connecting the gage to the Oil Temperature Probe broke. The
probe is inside the Oil pressure housing on the back of engine.

Can the line be reattached to the 2 inch long Copper probe by welding?
I believe the gage works under capillary effect.

Are there any Cessna approved replacements for the gage, line and probe or
do I have to replace with the Cessna OEM part? A Cessna dealer told me the
gage is either made by Stewart/Warner or Rodchester and costs around
$300-400.

Replacement Temperature gage and probes for homebuilts seem to cost around
$90.

TIA, John