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JRHaelig

Are 1939 Radiators Pressurized?

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After previous test drives of only a mile or so I took my '39 for a slightly longer drive today, only to puke coolant after a couple of miles.

 

My radiator cap has no sealing capabilities, but since my '39 Ford is a zero pressure system I assumed the Buick was, too.  (Brilliant, I know...)

 

So - am I wrong?  Are they pressurized? 

 

If so - are the caps a retail items (NAPA, etc)?  What pressure rating?

 

I did a vinegar soak of the block and radiator, and had good gravity dump on the radiator when I filled it and pulled a stopper out of the bottom outlet.

 

I'm pretty confident that I'm going to learn that these are pressurized systems and/or the velocity of the (new) water pump at speed just blew coolant past my loose cap.  At least that's what I'm hoping........

 

Thanks for the education.....

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My '40 has a 7 pound cap which is so rusted it doesn't seal. I doubt I'll ever fix it because the car runs fine the way it is and it's a daily driver.

 

If I fill it cold to the top (when the water jacket and heater coil are already full) it pukes the first time I take it out, because the water expanded. Then it runs fine all year that way.

 

I read somewhere but might remember wrong that '40 was the first year to have a 7 pound cap. I can't find the reference now.

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According to CARS  Inc. catalog (oldbuickparts.com), 37 - 39  use an RC-10 non pressurized cap.  The overheating may be caused by sludge  (rust, scale, etc.) in the block, generally near the rearmost cylinders. This can be cleaned by flushing, but the best way is to remove the rear freeze plug and to get the  sediment out.  On my 47 248, I too did the fill it up and see how fast the water runs out 'gravity' test, which I thought went well, but I went and had a new radiator core done and it solved the problem. If you record the radiator, be sure to put a coolant filter (Google 'gano filter' ) in the upper radiator hose, to keep any remaining block sediment from moving into the new core and ruining it.

There are numerous threads on this forum that cover this topic of overheating and sediment in the Buick 8.

 

Good luck!

 

Jack

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Sorry for assuming that you were overheating, if you are filling the radiator to the top, it will puke out a bit of coolant until the coolant is about 1 1/2 inches below the  top.  This allows for coolant expansion. There may be a fill line embossed in the top of the radiator tank on the engine compartment side.

 

Jack

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Gee, Jack -

 

I assumed I was overheating, too.

 

I did fill to the brim.  Did it again, too, for the trip home.  Took 2 qts to get to the lip again. 

 

Maybe I do just have expansion.  My needle wasn't pegged, but I wasn't trusting it, either.

 

I'll try to get those 2 quarts out and try again.

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All these old cars have to have an airspace at the top of the radiator due to the expansion of the water. It sounds normal to me.

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Two quarts does seem a bit much for the puking, is your temp guage indicating that it is going toward 200ish?  Mine wold be ok on cool days but I took it out on a hot day and when I stopped, it really let quite a bit of coolant out and the engine was running hot.  I did the gravity test on the radiator, the block seemed clean, but it would not regulate temp well.  Re-cored the rad, 160 thermostat (a bit low, I think a 180 may be better for the car), and now the car holds 160 all of the time, and only heat-soaks to about 175.  My 47 uses a 7 lb cap.  

 

Jack

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Mine only pukes when I shut off the engine. I guess when the water pump is pushing into the block it keeps some air space at the top of the radiator, when you shut the engine off the water suddenly pushes back into the bottom hose into the bottom of the radiator and..... green puke from the top.

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