We have a few pressure gauges at the shop that are low on oil what kind of oil is that?, id like to top them off better.
OIl filled gauges, Oil?
- Thread starter daman
- Start date
Typically mineral oil but I've seen silicone oils before too.
Manufacturer should be able to tell you if it's not on the gauge.
Manufacturer should be able to tell you if it's not on the gauge.
Actually, most are filled with glycerine. Occasionally you will find one filled with silicone oil. Remove a few drops from the gauge and see if it mixes with water. Glycerine will, oil won't. You should never fill them completely, always leave an air bubble. When the Bourdon tube is pressurized it expands and displaces a very small amount of the liquid. Liquid does not compress, so there has to be a little air to absorb the expansion in the gauge.
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MolaKule
Staff member
In some cases it was a highly refined mineral oil with a bit of diphenylamine.
Have no idea what oil is in there the gauge is old.
would A/C oil or Vacuum pump oil work?
would A/C oil or Vacuum pump oil work?
If the works are made of brass, you could drain it and fill with glycerine (if not subject to freezing temperatures). You can't go wrong with silicone oil. A compromise would be to drain and fill with a clear oil (light machine oil, vacum pump oil, compressor oil).
Glycerine if designed only for hospitable temperatures. Silicone oil if designed for very cold weather, though you want to put in whatever is already in them, silicone isn't so easily cleaned out if you wanted to switch.
And not all liquid-filled gauges are completely filled either. "Low" may be a relative term.
4WD
$50 site donor 2024
Guys these are half empty or a little less, its hard to see the numbers if its at a certain spot.
we have AC oil and Vac oil that's clear
we have AC oil and Vac oil that's clear
You should first determine whether they are filled with glycerine or oil. If you mix some with water and it mixes, then it is glycerine. If not, then it is oil. If oil, drain out what is in there, rinse with alcohol, dry, and refill with Vac oil. If glycerine, refill with glycerine (available at drug stores). Better yet, you could remove them and send them to a calibration lab for calibration and service. If they have leaked out half of the liquid, they are probably not reading correctly and should be calibrated.
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When I can ill try that
