offroadrolls
Well-known member
Not really an electrical question but kinda.
The mechanical temp gauge in my old Volvo does not work, you know, the kind with a capillary tube. So I did some investigating to find out how they work. I learned the bulb on the end of the capillary tube that’s screwed into the engine is filled with a gas, ether to be specific. When it gets warm it expands thereby actuating the mechanical gauge on the dash at the other end of the tube. It’s a sealed unit. If the tube gets crimped it will not work. Or worse, if it gets a hole in it the gas escapes rendering the gauge inoperable. So continuing my studies I found that they can be repaired by grafting a good tube with its gas from a working gauge to the tube on your gauge. The trick is you have to keep the bulb from the good gauge in ice water lower than the rest of the tube while you cut the tube and solder a copper splint you make to graft the 2 tubes together. Keeping the bulb from the good gauge in ice water keeps the ether liquefied in the bulb so it won’t escape the tube when you cut it. Sounds like a good way to waste a Saturday afternoon. I’m gonna give it a shot. Has anyone ever tried this? Or does anyone know a better way to repair a mechanical temperature gauge?
The mechanical temp gauge in my old Volvo does not work, you know, the kind with a capillary tube. So I did some investigating to find out how they work. I learned the bulb on the end of the capillary tube that’s screwed into the engine is filled with a gas, ether to be specific. When it gets warm it expands thereby actuating the mechanical gauge on the dash at the other end of the tube. It’s a sealed unit. If the tube gets crimped it will not work. Or worse, if it gets a hole in it the gas escapes rendering the gauge inoperable. So continuing my studies I found that they can be repaired by grafting a good tube with its gas from a working gauge to the tube on your gauge. The trick is you have to keep the bulb from the good gauge in ice water lower than the rest of the tube while you cut the tube and solder a copper splint you make to graft the 2 tubes together. Keeping the bulb from the good gauge in ice water keeps the ether liquefied in the bulb so it won’t escape the tube when you cut it. Sounds like a good way to waste a Saturday afternoon. I’m gonna give it a shot. Has anyone ever tried this? Or does anyone know a better way to repair a mechanical temperature gauge?