They now fill that tube with methylene chloride (paint stripper solvent base) I believe. Carter's has them rebuilt by a guy locally and it's less than $50/guage. If you call them, they can hook you up. Find a pre '50 GMC 228 and you can remove the electric temperature sender and the thermostat housing together. Then replace your capillary tube guage with an electric one from a GMC! Post 1950 GMCs used the capillary guages too.