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Bob, my first Buick was a 1940 Special back when it was just a used car. 1954, to be exact.

 

  If the coolant continues to heat past the thermostat temp while driving, the radiator is almost certainly partially plugged. NOTHING will clean it except to remove and have it rodded out. Everything else is pi++ing in the wind.  Spray the radiator with a garden hose next time it is run, after coming up to temp. The part that STAYS wet after a few minutes is plugged.

 

  Ben

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Ben's check works well and I used it on my '40 LTD.

Did you do the standard bypass valve fix yet ?

Just below the thermostat is the bypass valve housing, where the big hose comes up from the bottom of the radiator.

Pull that housing and discard what ever is left of the valve. You may have to grind out the brass shaft, if it's still there.

Tap in a frost plug of the correct size, and drill a 5/16" hole in the center.

I did this fix, as was recommended here on the forums, after fighting overheating for about 3 years, and it fixed it immediately.

This fix lets the hot water out of the head, instead of being "overpowered" by the water coming up from the radiator, as it's being sucked into the pump.

 

Mike in Colorado

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Ok, have a question for Flyer15015, i have took the bypass valve housing out and see the brass valve and shaft inside the housing, once out i dont understand what you are saying about taping a frost plug drilling a 5/16th hole in the center?, Hope you can reply to this, thanks Bob

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  If you go to the 1936-1938 Club website they have become custodians of the old 1937-1938 newsletters and an index. You can find a few articles and descriptions there. I've never felt the need to do this with my 1937.

 I believe this is what the finished product is supposed to look like;

Bypass_Mod_Bottom_Inserted.jpg

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Posted (edited)

This is how I did my ‘38 Special.

 

Used all the bits from standard and  added some brass tube from K&S Engineering (hobby shops keep it) to prevent the valve moving against the spring.

 

The tube goes over the centre brass rod and keeps the first brass cup from seating on the cast housing. You can see this better in the second picture.

 

This keeps a restriction on the flow yet allows it to bypass until it reaches the thermostat. So far it keeps good operating temperature but I also have the benefit of a recorded radiator and rebuilt water pump.

 

used a brass split pin before the install too!

Rodney 😀😀😀😀😀😀😀😀

 

AAB1592A-D0A1-4B33-8353-16804BFEB06A.jpeg

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Edited by rodneybeauchamp (see edit history)
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20 hours ago, 1937-44 said:

  If you go to the 1936-1938 Club website they have become custodians of the old 1937-1938 newsletters and an index. You can find a few articles and descriptions there. I've never felt the need to do this with my 1937.

 I believe this is what the finished product is supposed to look like;

Bypass_Mod_Bottom_Inserted.jpg

 

Papa,

1937-44 has it exactly right..............

Get rid of whatever is in there now, and DO THIS, and don't look back.

You will thank me  later.

 

Mike in Colorado

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Posted (edited)
On 7/5/2019 at 11:17 AM, 27donb said:
On 7/5/2019 at 10:59 AM, 1937 Buick 66C said:

Good Morning all,

 

These engines do not cool properly without the thermostat, therefore you should put it back in at your earliest convenience.  As Matt Harwood indicates, having the temperature climb after shutdown is a result of "heat soak", meaning the residual heat in the engine is not being removed by circulating coolant after shutdown.  I've found it very effective (and less mess on the garage floor) if I restart the Buick about 5 min after hot shutdown to allow the coolant circulate for a minute or so which will bring the temperature down very quickly.

 

Or, just don't overfill the radiator. 

 

Recently on a 90 degree day I took my 27 (different animal, I know!) for a state inspection sticker.  I had to wait over 30 minutes in the hot sun.  I shut the motor off, the dash temp gauge soared to over 200 (max on the gauge), the motometer read in the top circle, and I lost no coolant from the radiator because I left room for expansion. 

 

Are 1940's Buick cooling systems pressurized?  Makes no difference.  Pressurizing 50/50 antifreeze and water raises the boiling point, does nothing for expansion, so you can still get leakage out of the overflow if you are over full. 

 

My 27-25 has no thermostat installed, and no restrictor plate, and runs and cools fine.  Warm up takes longer for sure, in the cooler months.

 

My 27-54CC still has a working thermostat, and running and cooling was always fine.  When I removed the engine to do some other work, I pulled all the freeze plugs and replaced them with temporary expandable rubber ones, leaving one freeze plug hole open.  Then I would back flush the jacket with a hose, and alternate the open freeze plug hole, even having two open holes and hosing through the freeze plug hole and out other ones, all around. 

 

What I found was a lot of rust, sediment, rust, and rust that came out.  The head plugs were particularly gunked up.  After the jacket dried and all the temporary rubber plugs were removed, I used a strong rare earth magnet and compressed air to painstakingly clean out all I could before reinstalling brass freeze plugs.

 

I'm glad I went through the process, and would do it again if I were inclined to remove another engine and freeze plugs.

 

The result?  No change or improvement in temperature control or cooling of the engine. 

 

From my experience, if I knew the day I was going to drive my Buick was going to be hot, sunny, 95 degree temps and I would have to try and maintain 45-50 mph for stretches of time, I would expect my engine to run near the top of the gauge (200), and I would not put myself or the car in that situation and would stay home.  That's just me!

 

As I said before, I think these temps are normal for engines of this vintage being driven under the described conditions.

 

Edited by 27donb (see edit history)

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Ok everyone, i would like to thank all with their advice and how to"s on my heating problem of my 40, took all advice and followed as follows, found out the radiator and a small leak and blockage, took out the bypass valve housing, installed frost plug with the 5/16th hole in it, did not fill up the radiator to allow for expansion, AFTER ALL OF THAT, GUESS WHAT------SUCCESS WHOO WHOO, it runs around 160-170 degress, took it to a show about 10 miles from me, on the interstate driving, and to top it off, my 40 won best of show, so to everyone who helped me get this problem solved, a much appreciated thanks, thanks Bob!

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You are welcome and congratulations on your win.

Now go out and play with her...............

 

Mike in Colorado

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On ‎7‎/‎26‎/‎2019 at 12:09 PM, 27donb said:

 

 

From my experience, if I knew the day I was going to drive my Buick was going to be hot, sunny, 95 degree temps and I would have to try and maintain 45-50 mph for stretches of time, I would expect my engine to run near the top of the gauge (200), and I would not put myself or the car in that situation and would stay home.  That's just me!

 

As I said before, I think these temps are normal for engines of this vintage being driven under the described conditions.

 

 

Sounds like my old Satoh diesel tractor. Runs great but overheats when the temperature is above 75 or 80. Operate it with the hood removed and it's good to maybe 85, but when it's 90 forget it.

 

So, I mow in the morning when it's cool, no problem.

 

latest?cb=20151106210615

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