New for  FEBRUARY 2015 comes another highly unique motor temperature indicator not normally seen on the market or in any motometer collections.


The goal of this sction is to expose site visitor and motometer collectors of and on some of the most rare or unique motometers ever created.


The featured items in this section is subject to and will change periodically, so we encourage MotometerCentral website visitors and subscribers to regularly check this site area.


Enjoy this section.  And, keep your eyes open so that you can find yours!






The Citroen automobile company was founded in 1919 by Andre-Gustav Citroen.  Mr. Citroen possessed a brillant engineering mind and his automobile company was well-noted for its industry innovations,.  Some of these innovations were front-wheel drive, four-wheel independent self-levelling suspension, unitary body design, swivelling headlights and pioneering the use of angular cut gears to facilitate more efficient gear engagement  and efficient interaction.  The company's use of the double chevron symbol is an homage to the gear system design.


Classic Citroen Website writer Karel Beukema toe Water published an article on 24 January 2012 that perfectly summarized the Citroen ""Moteur Flottant" engine as follows:  "The wing ornaments that can be found on Traction Avants are meant to symbolise the wings of a swan. The swan was used by Citroën stylists in the early '30s when they introduced the "Moteur Flottant". This was the result of their acquiring a license for the "Floating Power" engine mounting system from Chrysler in 1932. The essence was that engines were no longer bolted to the chassis, but were suspended by flexible rubber mountings, thus significantly reducing the transfer of vibrations from the engine to the rest of the vehicle."  (Citing below)


The "Moteur Flottant" temperature indicator definitely meets the qualifications to be showcased within this section.  It is a rare, one- of-a kind or sole survivor type instrument.


It was designed to fit on a circa 1934 Citroen automobile radiator. Vapor from the radiator collects in the diaphram (see under side view) where the steam temperature interacts with the included thermometer bulb (hidden from view).  The thermometer is Centigrade calibrated to show/indicate temperature between 20and 100 degrees Centigrade.


The indicator has the "Moteur Flottant" logo symbol on a release button.  Pressing the release button would allow fresh coolant to be added to the radiator tank.


This temperature indicating instrument was located and imported into the U.S. from France.  And, is a welcome addition to our overall collection, the French section and Ultra Rare and Unique section.


No patent have so far been found respective to this gauge.


Nonetheless on its underside are the number series 6991.1, 4 and the word "ALUVAC."  The underside of the release button has the parts number (?) 6990 and 5 (stamped in a circle - a possible inspector's quality control stamp/mark),  however pursuit of information using them has yet to yield viable results.  No other maker or manufacturer's mark are available.


The indicator is made of a very lightweight non-magnetic alloy, possibly aluminum, (hence the "ALUVAC" phrase under the cap).  It has a chrome paint finish.  The thermometer curves at a 90-degree angle to fit within the vapor collector.  Its overall length is a little under 5-inches.  And, it was design to lay horizontally against the auto's hood.


The horizontal seating design is, however, inherently problematic as thermometer indicator fluid naturally wants to creep upward along the tube's inner wall.  Combined with coolant temperature driving the fluid ever higher it is quite easy for the instrument to fall out of proper calibration and be rendered relatively useless.  Thus, it is easy to conclude that these gauges might have been meant to be generally disposable.  If disposable, that would explain why no others are known to exist.


When we received this gauge it had an elevated temperature indicating fluid level.  It took some time to figure out the proper re-calibration technique, particularly given its apparent delicate construction and non-availability of replacement parts.  Nnetheless, it has been returned to factory correct indicator working condition (See above, first image).  The release button has always functioned properly since our guardianship.




The quoted "Moteur Flottant" information comes from the Classic Citroen website. 


Please Click the following link 




to learn and see more about Citroen cars and history.


We encourage you to visit Mr. Beukema toe Water's website for more in-depth and fascinating information. 

Patent Information

None Known




Posted: February 2015




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