Trying to troubleshoot a cooling problem . . .

[av8]

I spent a couple of hours today, cleaning and checking resistance of a couple dozen old flathead temp senders. Found a few outright duds, but as the numbers were posted it looked like I'd discovered a baseline spec in the mid 13-0hms range -- about 10 senders that were almost all identical. So, I replaced the bad 'un with a good 'un and . . . the gauge would still not drop to zero with the ignition switched on! ARRRRGH!

I then substituted a sender with a greater risistance -- about 17 Ohms -- and the nothing positive happened. Being very clever, I then stuck in one that checked out a 9 Ohms, and finally, the gauge dropped all the way to zero with the ignition switched on! Nothing to do now but confirm the sender's operation on the trip home from the shop -- during which time the gauge never moved off of zero!

I'm going to take a step back next week and reinstall one of those mid 13-Ohm senders and see what it does, then one with a bit higher resistance, and so on.

I'm rethinking the "purity" of my instrumentation, particularly with a new motor to come over the Winter. I just checked my PAW catalog and see that I can get their "house" mechanical gauges for $21.00 each so I can monitor both banks as Jay suggestsm and for another nine bucks I can get a plated under-dash panel to mount them. When I compare this to the cost of new electrical temp senders for the original uncertain gauge (which would need that clever toggle-switch scheme) at $35.00 each, the PAW mechanical gauges look to be way to go.

There's ample room to mount the panel on the lower edge of the dash on the left side of the steering column,  so it appears my direction is clear. Now, anyone have any trick ideas for taking up about 3-feet of slack in 6-foot capillary tubes?

[Charlie Chops 1940]

There's ample room to mount the panel on the lower edge of the dash on the left side of the steering column,  so it appears my direction is clear. Now, anyone have any trick ideas for taking up about 3-feet of slack in 6-foot capillary tubes?

As I remember the capillary tubes are pretty flexible - coil them up and tie them to something behind the dasH?

[av8]

[As I remember the capillary tubes are pretty flexible - coil them up and tie them to something behind the dasH?

Yes, I've done that in the past but it looks sort of untidy, although no one looks under the dash, so maybe I'm being unnecessarily fussy.

I was hoping someone might have a neat trick for shortening capillary tubes.  

On a serious note, I can run the tubes through the firewall wiring insulator and make neat turns with them and secure them to the wiring loom. Hey, this is starting to sound pretty good!

[enjenjo]

There is a guy up here that will make the capilary tube any length you want. It costs $175, each. The capilary tube contains a precise amount of ether alcohol, which by expanding and contracting, moves the needle.

I would coil it neatly, but your call.

[av8]

There is a guy up here that will make the capilary tube any length you want. It costs $175, each. The capilary tube contains a precise amount of ether alcohol, which by expanding and contracting, moves the needle.

I would coil it neatly, but your call.

Thanks, Frank. I think I can live with the neatly coiled tubes after all.

[enjenjo]

There is a guy up here that will make the capilary tube any length you want. It costs $175, each. The capilary tube contains a precise amount of ether alcohol, which by expanding and contracting, moves the needle.

I would coil it neatly, but your call.

Thanks, Frank. I think I can live with the neatly coiled tubes after all.

Thought so.