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    Does anyone know if the V-12 engine had one or two thermostats in them?


    Tim Jones


    Hi Tim,

    The 1932 to 1938 V-12’s (as well as the 8’s) did not have what we now think of as conventional thermostats that control the flow of water (in the cylinder head water outlets).

    Instead, they had a (one) bellows assembly in the upper radiator tank, filled with ether, that would expand when the temp reached about 165, and push a lever that cranked the grille shutters open, allowing air to pass thru the radiator. The original units were titled “Sylphon”, and reproductions are still available.

    Any attempt to put conventional thermostats in would be redundant at best, and could hinder the cooling system.




    A discussion about these late thermostats came up at lunch yesterday. I called Dave Murray to see if anyone but Bill Hirsch was selling these. Apparently not, and they are $275! The later thermostats are totally different from the ’31 and back. The early ones can be rebuilt, the later ones cannot. (supposedly) The housings on the early ones are perfectly round, the later ones have a flat spot on the top part of the housing.


    Tony, I noticed a $100+ jump in these “t”” stats too. They were $135-$160 for a long time.”


    I know this is an old thread, I specifically searched for it.

    I have a brand new Sylphon thermostat/control device, it has two flat spots, top and bottom, in the flange.

    Am I correct in thinking, from Tony’s above post, that this will NOT fit my ’31 Model 43?



    Can you post a photo of it? If it won’t fit your ’31 and it will fit my ’34 1240A, I’d be interested in buying it if you’re in the market.



    Anyone have a thermostat for a ’29? I just had the radiator done at David Coco’s recommended guy in Winchester (who is good by the way), but need a thermostat to complete the setup. It is one of the Pine Winterfront types. Still waiting for the engine rebuild to be completed…

    One more thing. My car has a built in heater, but I have no idea how the heater hoses are hooked up. Does anyone have a picture or diagram to share?


    Cislak will have some early thermostats.


    Here’s one pic, I’ll post another, no, I don’t need it, if it’ll work for you email me and we’ll work out a price, it’ll be less than Bill Hirsch price of $370!!


    another shot, this doesn’t fit a 31, correct? Someone?


    No this is the later one.


    Thanks. dc



    I’ve attached a photo of one from my car. They are certainly a different design and I’m not sure if yours has the proper amount of travel to operate the louvers. Has anyone installed one of these on a 34-35 12?



    Center rod is threaded to install the slotted adapter shown in your picture.

    Thanks to the miracle having a stove, pot of water, and a meat thermometer:

    Rod begins to extend at about 125 degrees F, is fully extended somewhere past 150 degrees F.

    Full extension is 3/4 inch, from room temperature and then measured at 200 degrees F.

    Bolt hole circle, center of hole to center of hole, is 3-7/8 inches.

    Hope that helps.


    Yup, I think we’re good. I’ll contact you offline.



    I tried a number of things to control coolant level on our 1247. One of the best improvements on the road to a cool tourer was installing an inline thermostat (175 degree Mustang application) in the drivers upper hose. This seemed to help balance the two sides of the coolant cycle.

    I had blocked the original thermostat to keep the shutters open full time, but of course we are focused on touring the car and never do judged shows. Because we don’t drive our cars in winter conditions, restricting air flow through the radiator doesn’t seem to have any desirability.

    Equally important to thermostatic control is a functioning oil cooler, proper water jackets & tubes, an effective radiator core, a water pump with good vanes and low clearances to limit foaming, and properly advance timing. It took us 6 years to get everything right on the 1247, but the result is really ‘cool’!


    Would anyone know where I could buy a thermostat for a 1923 Pierce Arrow. Or is anyone selling one that we could purchase.  It has the Inline 6 Dual valve and the thermostat we pulled out of it was very corroded.  Contact us at this phone number 615-765-7076


    To Bob Coates:  Recently I changed the upper hose in my ’29 to get rid of the old  Toyota molded hose that a previous owner had installed. The new straight hose having a thicker wall didn’t bend, so I had to remove the coolant elbow from the block to make it fit. A surprise in there was a modern 165F thermostat. Not sure if there was a spot for it to fit originally, or someone machined it,in the elbow, block, or both. The car stays cool even on hot days with the gauge needle in the middle of the range.  The radiator has the original bellows thermostat parts installed, but no idea if they are functional. If the shutters stay open, that would explain why the car has a chromed stone guard to hide the black shutters.  If your car is apart enough to machine the elbow or head, it may be a reasonable alternative to having a long fight with the original bellows unit.  Good luck and no matter which way you decide to go, keep you cool.   Herb

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