Bypass Thermostat?

Jon B
Jon B Administrator
edited November -1 in HUDSON
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Is this a bypass-type thermostat? If so, is some sort of o-ring required or can it go right in?

Comments

  • Unknown
    Unknown
    Looks just like the bypass thermostats I have. The instruction sheets I have make no mention of an O-ring but do suggest using a new gasket between the thermostat housing and engine head.
  • dwardo99
    dwardo99 Expert Adviser
    They just fit in with no o-ring. Make sure all the crud is removed from the inset where it fits or it may prevent the housing from making a good seal and it will leak. DAMHIK.
  • [Deleted User]
    [Deleted User]
    Jon

    Looks like a bypass stat to me . No oring required. My 37 terr. has a regular non bypass thermostat. I dont know which is better but i like the looks of the non bypass set-up if that means anything to anybody but me.

    Chuck G.
  • hdsn49
    hdsn49 Senior Contributor
    John



    Be careful tightening done the themostat housing. Both my brother and I have broken the housings when tightening because the themostat was not properly centered in the housing.
  • Jon B
    Jon B Administrator
    Thanks for the responses, guys! I picked a NOS one up at a giant hotrod show in Rhinebeck, NY, from the 'three for $1' box. I'm happy to discover it's the 'bypass' type that I can use as a spare.
  • nick s
    nick s Senior Contributor
    hdsn49 wrote:
    John

    Be careful tightening done the themostat housing. Both my brother and I have broken the housings when tightening because the themostat was not properly centered in the housing.

    TIP: use gasket sealer to "glue" the thermostat into the housing. it wont slip off center and break the housing.

    Jon, i didn't think the splasher six used the bypass type (just the eight) please enlighten me. thanks
  • Jon B
    Jon B Administrator
    Doesn't matter what it SPOSE to use....that's what it has NOW! LOL!
  • nick s
    nick s Senior Contributor
    Jon B wrote:
    Doesn't matter what it SPOSE to use....that's what it has NOW! LOL!
    no criticism intended jon, just expressing curiosity.(great answer though)

    so is it SPOSE to be a non-bypass? i was asking because i thought you see eights with the six cyl housing NOW LOL to avoid needing the bypass thermostat and don't see sixes with the eight set up for the same reason.
    honestly i am just trying to build on my knowledge, do you run an 8cyl waterpump or does the six have the port as well? to try and settle my curiosity i dug into a book on my desk i saw a '40 eight with non bypass housing and water pump and a 36 tplane with bypass waterpump and housing. i'm confident that the eight is not as SPOSE to be but is the Tplane as intended?:confused:
    thanks
  • Jon B
    Jon B Administrator
    Well, this gets into a rather deep level or arcane minutia, but it looks to me as though Hudson used a regular and by-pass water pump, depending upon model, at least in 1937 and probably in other years as well.



    The 1937 parts book lists two water pump outlet necks available: one for the Terraplane six commercial cars and 'Deluxe' model, and the Hudson six business coupe; the other for the Terraplane six 'Super', the Hudson six, and the Hudson eights. This second neck I take to be the 'bypass' model though the parts book doesn't specify either one as regards 'bypass-ness'.



    The 1937 service manual reinforces this supposition, stating that all 1936-7 models except the lower-priced Terraplanes (it omits mentioning the Hudson six business coupe) used the type of cooling arrangement with a bypass feature. (Maybe the cheaper cars had no thermostat at all; the parts book only lists one thermostat and it's for the higher priced Terraplane and all Hudson models except the six-cylinder business coupe!)



    So....at least in 1936 and 7, it looks like all 6 and 8 cylinder Hudson and Terraplane cars had bypassing cooling systems except for the very cheapest models.



    I have seen two types of necks for sale at Hudson flea markets: plain and bypassing (sometimes you see bypass types for sale with the bypass port sealed with a pipe plug, rendering them usable in the cheaper cars).



    To complicate matters, I have also seen a second bypass neck in which the port (to the water pump) comes off at a different angle. And I've seen water pumps whose bypass outlet only matches that particular angle. So, it would appear that if one intends to use a bypassing pump, one must get the mating pump and bypass! Possibly these were used in some of the postwar eights?



    Obviously, folks need only to buy a plugged neck and a pump with the bypass outlet plugged as well, in order to jettison the whole by-pass concept. Both types of pump / neck bolt to the cylinder head and block. I've seen a lot of non-bypass setups on premium-model Terraplanes and Hudsons over the years (which should use the bypass type), so a number of folks have opted for the non-bypass pumps.



    So, there we are, aren't we! Hope I didn't put you to sleep with this discussion!
  • nick s
    nick s Senior Contributor
    thanks jon
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