37 Hudson Terraplane six oil

ei_mooseei_moose Member
Hi, I'm wondering what engine oil you guys run in these older vehicles - I'm currently running 15w-40.

Also I have attached a picture of an opening above the rear differential and am curious to what it's purpose might have been.



  • Jon BJon B Administrator
    edited August 2017 Posts: 6,614
    The opening is for ventilation, the fabric is a filter.  Don't know why there is a hole in your filter, though.

    Almost any modern oil is okay.  Some say that using a detergent oil in an old motor that hasn't been rebuilt, is bad because the detergent loosens dirt and gunk, and puts it in the system.  (The same reasoning holds that it's okay to use detergent in a rebuilt engine because there is no gunk to be loosened).  Others say this is an old wives' tale.

    The other controversy regards zinc dialkyl dithiophosphate (zddp) in oil.  It used to be there, then was taken out.  Some say there is more wear on the cams because of the absence of zddp in the newer oils.  Others disagree.  If you like zinc you can buy certain motor oils that contain zddp.  I personally choose to use "Brad Penn Racing Oil" with zddp in my '37, simply because I don't want to gamble.  But as I say, there are others who disagree!
  • ValVal Member
    Posts: 537
    I have the same vent filter in my 39 and I have the same cut out (hole). So far as oil I use Shell 10W 40  with Lucas oil additive.  
  • ei_mooseei_moose Member
    Posts: 2
    Good to know, thanks for the quick response
  • Uncle JoshUncle Josh Senior Contributor
    Posts: 2,513
    15-40 in all my splashers
  • KustomKreepsKustomKreeps Member
    Posts: 247
    Over here in NZ we have a brand Penrite that make oil for old cars full zinc low detergent. I use that often.

    But the times I have been stuck with out it I go for something with high zinc.
    Diesel oils work better than many car oils on many of the older engines I have had.

    49 Hudson Build thread (picture heavy, may need to refresh if images dont show.)
  • dlamb67dlamb67 Member
    Posts: 17
    I'm a luddite still use 30W Castrol. I have thought about going to a multi viscosity.
  • dlamb67dlamb67 Member
    Posts: 17
    I would cover that hole too, I had mice get into mine and build a nest under the rear seat. Even if you pull the seat and place a board over the opening when in storage.  
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