1951 Hudson Hornet 308 Cooling System - Details

Alright, so I wanted to document what I did to get my cooling system connected and updated.  I was new to this before I did it and gathered information from all over to put it all together.  Hopefully someone new will find this a little easier/central to reference.  I used several posts from this very forum, as well as documents around the web .

So, I started with trying to track down a new/better radiator.  I have the original, but it's pretty beat up, and I have some tubes leaking that need repair.  Plus it has several spots that have already been repaired.  https://hudsonrestoration1948-54.com has several articles about which ones have been found to fit "best", as well as other options.  I chose to go with a 3row aluminum radiator out of 1976 Dodge B300 440cid van.  This one was on ebay for $200!  I bought it expecting to have to modify the bracket, but when it came in, I found out it fits really nicely between the radiator uprights.  I drilled a couple of holes in the bracket and mounted it using some existing bolts (fender adjustment of some kind...I haven't gotten THAT far yet).

Radiator Hoses
Then it was on to the radiator hoses.  Found several posts in this forum about some Ford hoses that work.  I went that route and they worked really well.  Upper - Gates 21631- 1994 Ford F-150 5.0L,  Lower - Gates 21794 - 1998 Ford Mustang 4.6L.  I got mine from RockAuto for really cheap.  Under $30 for both of them and shipping.

Mine had the optional thermostat delete when I got it (this is sarcasm).  I used a 160deg Mr. Gasket thermostat (4366) and found a place on ebay that was selling OE gaskets (still available as of 8-2019).  A 1/8" bleeder hole in the thermostat and some massaging of the gasket for that and it was ready.  While I was in there, I also plugged the bypass with an 1.25" plug.  Drilled a 1/8" bleeder hole and used some sealant to hold it in.  This forum and other sites helped with all the details!

Water Pump
Found a new pump on ebay.  Works great!  I ended up needing a longer bolt in the body to help with my alternator mounting, but that was simple enough to change out.  They even sent me a new gasket when I messed mine up.

Coolant tube.
What a mess!  Mine had been severely mangled inside the block.  As in, you couldn't tell it was there or what it was.  I had to ask on this forum just to figure out what I was trying to get out and replace.  If you are skilled in metal work, I'm sure this could be copied with time, but I was lucky enough to have someone point me in the direction of someone who had one.

Heater Hoses
Replaced them.  Not much else to say.  There are several posts about which to use.  I went to the local green parts house and picked through the ones I thought would fit best.  I don't have the metal tube that connects to the water pump, so I bought a nipple and hose with a single 90deg bend in it.  The U-shaped hose was the most difficult.  The one I found seems to be 3/4" instead of 5/8" so I'm hoping the clamps will hold it well enough.  No leaks so far.

I used the original!  It's a little rust pitted, but it seems solid.  Maybe once I get to actually driving it, I'll be able to tell if I need more air flow, but until then it seems to keep the engine cool enough.  I also plan to make a shroud for it.  I read that the OE setup was to seal all around the radiator so the fan draws more through it, but the new radiator I got has studs to mount a shroud to, so why not use it?  I might try to find an OEM shroud for the Dodge van and see how it fits.  I also think it will make me feel better working under the hood while it's running...that thing is wide open.

Freeze plugs
The three on the left side of the block were GONE.  So I replaced them with some I thought would work.  I think they are too thin and don't have enough surface area to contact the block.  I say this because after about 20min of running I blew one out, completely intact, along with all of the 160+ degree water!  Luckily I was standing right beside it.  So I'll have to find new ones and replace all three again.  I don't have the engine out (obviously) so I can't do any of the other plugs at the moment.

That's it for that piece of the puzzle!  Feel free to ask any questions, I've tried to not leave anything out.  Unfortunately I don't do well with taking pictures as I'm working.  I get more focused on the task and forget.  If anyone wants pics, just let me know and I'll see what I can do!


  • Is the heater water valve leaking yet? :)  I recently repaired mine, I can post pics if you're intersted

     Nice write up! thanks

  • I haven't seen any leaks YET, but I'll definitely take any preemptive repair pics I can get.  Just because it hasn't happened yet doesn't mean it won't.  I did notice my heater hoses aren't hooked up correctly, though.  I plan to fix that before I start it again.  Next up is getting those freeze plugs.
  • looking at pics of the engines, it appears there is another plug at the back of the block, near the top.... might be able to get it by removing the floor cover over the transmission?

  • Great info. Thanks for sharing.
  • I just wanted to let you know now, but please do some more research on it to make sure it's really there. usually the hard to reach ones, are the ones that fail when you're a long ways from home

  • squirrel said:
    I just wanted to let you know now, but please do some more research on it to make sure it's really there. usually the hard to reach ones, are the ones that fail when you're a long ways from home

    If you could send those valve pics, it would be great. I'm waiting on new freeze plugs, but decided to make sure I flushed out the heater core while I wasn't doing much. THEN I noticed water inside. I figure I need to get the valve and the core out for inspection/repair.  Anyone know if there is a workable replacement out there? Something Mopar, perhaps... 

    As for that other plug on the back, I'm pretty sure that's the 11/16" Welsh plug that is next to impossible to find. Once I actually pull the engine for rebuild, I'll knock that one out. It's not leaking yet so it's not high on my list. 
  • Glowplug
    Glowplug Expert Adviser
    Look st my website it shows rebuild info on ranco valve (heater valve)
  • squirrel
    squirrel Member
    edited August 2019
    here's the thread I posted on the HAMB. The valve seems to be working and not leaking. I added a few details that seem to be missing on some other discussions of how to do this.

  • Uncle Josh
    Uncle Josh Senior Contributor
    AE374 or FF209
    72 to 86 Dodge Truck/Van
    95+Honda Passport V6

  • Has anyone heard of putting a more modern (easier to replace) heater control valve in?  I've got the seal on order, but I was thinking since this is no where near a full restore, I don't have any problem using something else that is easier to get my hands on.
  • You can use any type of water valve that has the correct threads or barb fittings, to shut off water flow. The original thermostatic valve is a nifty thing, but not necessary at all...you could even just loop the hoses or plug the fitting holes in the summer, and connect it back in the winter. It was very common to install a manually operated valve at the engine, to shut off water to the heater. I think there is still one available.  let's see....

    be sure to check the sizes to make sure it would work, and that there's adequate room to be able to screw it into the head.