Diagnose My Temp Gauge

[Joe Flanagan]

So I put my temp gauge in a pan of boiling water and the needle barely moves. It does move, but it goes only about a sixteenth of an inch, to about the 130-degree mark. It won't go any further than that. When I remove it from the water, the needle returns to its original position.

I examined the tube and I can see no breaks. The mechanism that moves the needle seems to move freely. I can move it with my finger. There are no obstructions that I can see.

So I assume that because the needle is moving a little, the system is still closed and I have ether. I also assume that something is binding and preventing the needle mechanism from moving. Seems like the Bourdon tube wants to expand but it can't.

Anyone have any ideas?

[41/53dodges]

did you modify this at all, or is it stock?

when i finished repairing mine, it did the same thing because the tube that moves the needle moved when i soldered it all back together.

[Joe Flanagan]

No. This was a working gauge I got from Neil Riddle. It worked for about four months then suddenly stopped working. I haven't fiddled with it at all.

[Jim Yergin]

Joe,

Have you considered calling Neil Riddle and see if he has any thoughts?

Jim Yergin

[garbagestate 44]

You could probably manipulate the copper bladder a little (very carefully) to make the gauge read higher and calibrate it along a known temperature curve. The problem is that the bladder and related mechanism connected to the needle is very delicate not unlike a pocketwatch movement. Most pressure gauges work the same way regardless of rating. That's all it is. As the ether heats up it flashes to vapor and builds pressure which makes the bladder become stiff. I've worked in gas houses for 27 years and can tell you that the only difference in gauge pressure ratings is how thick that bladder is. The only other thing I can think of is that maybe it never had enough ether in the bulb to begin with. Good Luck

[Joe Flanagan]

Thanks. I have tried adjusting these things before and have done no good. I'd rather not toy with the mechanism. It did work for four months, so it did have ether in it at some point.

Jim, that's a good suggestion. I may give Neil a call.

[Plymouthy Adams]

when in the hot water, did you smell any trace of ether? if a slight flex fo the bladder moves the temp guageneedle then I suspect loss of ether from the bulb. This stuff though new is still over 60 years old..

[Joe Flanagan]

No smell of ether. The needle moves on its own for the first sixteenth of an inch and then stops.