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Water temp gauge reads low

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RickPA

RickPA

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My combo oil/water gauge was recently removed from the dash along with the other gauges. Now it reads low. e.g. 140 when it previously read 180. It does move but is consistently low. No idea how it happened. If anyone knows I'd appreciate knowing too. Any suggestions on calibrating, maybe opening the face and moving the needle? Or does it need to rebuilt?
 
First, verify actual coolant temp with an IR non-contact thermometer, or a good old kitchen thermometer. If gauge is indeed reading low, I can think of two possible causes:

1) the needle got moved somehow. Yes, you can remove the bezel and glass and re-position the needle--it's press-fit on a tiny spindle--but it'll be trial-and-error and you risk damaging a fragile mechanism, or
2) you lost some of the gas (ether) in the bulb, line and mechanism; though, I think this is unlikely because any leak would release all the gas (ether is HIGHLY flammable, so be careful if you do suspect a leak)

You'll probably need to get it overhauled; not cheap but it's important for the 'safety gauge' to be accurate. My oil pressure gauge used to indicate zero at hot, slow idle--obviously, I had oil pressure or the engine would have seized--but after overhaul I got 20PSI.
 
RickPA said:
My combo oil/water gauge was recently removed from the dash along with the other gauges. Now it reads low. e.g. 140 when it previously read 180. It does move but is consistently low. No idea how it happened. If anyone knows I'd appreciate knowing too. Any suggestions on calibrating, maybe opening the face and moving the needle? Or does it need to rebuilt?
Click to expand...
just talked to Palo Alto Speedo (https://www.paspeedo.com/) about restoring this gauge. The main guy there said if left alone the capillary will last indefinitely however once you start fiddling with it (like removing the gauge) you should probably replace the capillary as it uses ether which can leak quite easily once disturbed. He recommended replacing the capillary as a matter of course when removing the gauge for rebuilding. When they replace the capillary they also calibrate it so it should read correctly after that's done. I know they can do it as well as Nisonger (https://www.nisonger.com/) and I am sure there are others that can do it as well.

Cheers,
Dan M.
 
West Valley Instruments overhauled mine: https://westvalleyinstruments.com/

PA Speedo is good, too. Owner's name is Claus (if he hasn't retired; his son was running more of the show last time I was there).

My dad tried to repair one of these himself; he de-soldered the bulb, got some ether from the drug store and filled the bulb, and tried to solder the bulb closed. When the ether ignited, it sent the bulb across the shop like a 50-cal bullet (and it's just about that size and shape). Luckily, Dad was unhurt, but we decided to let a pro do this particular job.
 
Rick--

A while back I had to pull my radiator and obviously caused an ether leak that I ultimately had to have addressed by Nisonger. However it took a while--like a few weeks--for the WT gauge to become totally non-functional and at first the only symptom was a slight decrease in WT, then more, then nothing.....
 
Bob_Spidell said:
West Valley Instruments overhauled mine: https://westvalleyinstruments.com/

PA Speedo is good, too. Owner's name is Claus (if he hasn't retired; his son was running more of the show last time I was there).

My dad tried to repair one of these himself; he de-soldered the bulb, got some ether from the drug store and filled the bulb, and tried to solder the bulb closed. When the ether ignited, it sent the bulb across the shop like a 50-cal bullet (and it's just about that size and shape). Luckily, Dad was unhurt, but we decided to let a pro do this particular job.
Click to expand...
It was the son I talked to.

Cheers,
Dan M.
 
I moved the needle on mine as it read 25 degrees high at operating temp. Not difficult if you're careful. Safety gauge needles are heavier-gauge than the one in the fuel gauge which is evidently made of pie-plate stock.
 
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