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1939 Pontiac flathead six cooling


1964carlito

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I have successfully extracted many ( somewhere between 15 & 20) factory installed brass coolant distribution tubes from 31-36 Auburn 6 and 8  over the past 20 or so years. 

There is a lot of crud that builds up around the tube in the block. High pressure air or better yet a pressure washer will work to remove it.  

The science is true, but with the modern additives, I wouldn't worry about having it stuck in 100 years from now.  If ever.............

 

This is the tool I made 

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Edited by Curti
update (see edit history)
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poured gallon after gallon of water down where thermostat sits and drained it through the hole from the removed pet cock, block drain on LH side. Eventually water drained clear from a thick muddy consistency. Had to apply shop air to back flush to get initial water to drain. It's a start. Previous owner was running without a thermostat too. 

Edited by 1964carlito (see edit history)
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As mentioned several times above, always do easiest/cheapest things first before major dismantling...

AS already mentioned, get a fairly flexible soft wire and poke around INSIDE the petcock hole in all directions, while water running out,  to see what you can dislodge...the thick muddy consistency, if more than just a few second, may also be thru all your water passages...

Your block should have freeze plugs; you can pull one of them to see whats piled up behind it...

Last, but not least, on cars that've been sitting, after dark shine a light THRU the radiator, to make sure old spider webs or insect nests haven't blocked off a good part of the airflow the fan tries to pull thru the radiator...

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Now it's imperative that you use a stocking filter in the radiator.  Actually, at a minimum, I'd pull the radiator, turn it upside down and backflush the snot out of it before running the engine. Run as aggressive a cooling system cleaner as you can find (the old 2-part dry chemical is best, long unavailable in Calif), flush, flush, flush (12-15 times is not too much), after which use a new stocking filter as crud will still be coming out of the block for months as loosened by repeated heating/cooling cycles. 

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I had a 51 DeSoto with a brass water tube and it was good as new when I checked it, 60 years after it was installed. Have seen other brass parts and fittings in contact with cooling water that did not corrode. Now aluminum that is different, it will turn to powder if not protected.

 

Once again I suggest you do yourself a favor and diagnose the problem first, do not go tearing your car apart untill you know what is wrong. Spend 5 minutes figuring it out before you waste 20 hours tearing everything apart.

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So far I've pulled the block drain to flush block and drained radiator. Was able to open up clogged block (coat hanger) and got crud filled water to flow. I poured gallon after gallon of water down opening where thermostat sits. Found no thermostat installed. I'll install correct thermostat and gasket (parts on order) fill coolant system then ops test, flush to see where I'm at. The fan belt I ordered is wrong one. I need to research p/n order another. 

Edited by 1964carlito (see edit history)
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  • 2 weeks later...

Up date on the cooling issue with my 1939 Pontiac. The classic car gods must of looked down on me tonight. I was able to remove and replace the water distribution tube by simply tugging on original with a coat hanger. Prior to removing old tube, pulled radiator, removed water pump, disassemble water pump and found it blocked with debris. Cleaned it up and removed and replaced water tube. Now I need to order gaskets for water pump. I had to remove small portion of the front grill. 

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On 3/27/2017 at 1:43 AM, Tinindian said:

There is a coolant tube that circulates the water to the back of the engine.  These often rot out and need to be replaced

 

Nice car brings back GREAT memories,

My father had a 39 Pontiac, but his was an eight and the same problem was the water distribution tube rotted out. I remember replacing it sometime in the mid-70's 

Best of luck with the Pontiac, you just don't see them anymore

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