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1931 Chrysler CG Imperial engine over heating - straight 8 - 384 engine


Chryslerman1929
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Hello,

 

i have a 1931 Chrysler CG Imperial and have had the radiator recorded, pump overhauled and it is running hot.

 

juts running around the streets the temperature quickly runs up to180 and depending  on if i am stop starting running at low speed the temperature ranges between 160 - 180,

 

When i take it on a freeway the temperature runs initially at 180 for a few miles, then when i start to slow down on a off ramp it will climb to 180 - 200.

 

There does not appear to be a thermostat in the head and the radiator fins are opening  and shutting as they should see picture at the petrol station when running hot with vents open.

 

Some say maybe the pumps is pushing the coolant through the radiator to fast and not cooling enough?

 

Mechanic says when they had the head off it looked ok, when water pump was removed the block was clear behind the water pump , they are about to pull site plates off to check rest of block later this week

 

Love to have some feed back on thoughts on the above 

Engine.JPG

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Edited by Chryslerman1929 (see edit history)
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Did you flow test the new core in GPM? It should be 40 or higher. Ignition timing retarded? Why with all that work doesn’t have a thermostat? Is the lower radiator hose collapsing?  The water jacket covers should’ve been removed when the radiator was done. Did you check to see if the temperature gauge is accurate? It looks like an very nice car. You need to diagnose your problem, not just randomly changing and attempting to fix things. My bet is it’s an incorrect core. It’s very common today to see new radiators flow 30% to 50% less than factory.

Edited by edinmass (see edit history)
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The lack of a thermostat can sometimes cause problems.   Not intuitive,  but zero restriction of water flow causes the water to move too fast through the radiator and it doesn't cool.    Depending on the design, an open thermostat will still slow the water flow down.

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48 minutes ago, alsancle said:

The lack of a thermostat can sometimes cause problems.   Not intuitive,  but zero restriction of water flow causes the water to move too fast through the radiator and it doesn't cool.    Depending on the design, an open thermostat will still slow the water flow down.

Not AGAIN!

  I suspect Ed is correct.

 

  Ben

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OP says the radiator fins are opening and closing as they should. It seems this model controls temp by restricting air flow thru the rad, not by restricting coolant. You can see the big thermostat housing in the top rad hose with linkage to the radiator fins.

If you have a 180 thermostat it could be normal to run such temps. A laser temperature gun could be used to check thermostat opening temp. And confirm radiator and engine temp.

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In my experience decades ago, smaller 6-cylinder Chrysler products were known to have water circulating too fast through the radiator to cool -- adding thermostats helped. May be the case with the big 8-cylinder engines as well.  

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 46 to 48 Chryslers have a water tube that distributes the water rearward and sends it between the cylinders. It commonly has to be replaced.

 If yours has such a system, maybe it is rusted and not working correctly.

 

 Another thought, My Detroit 8V71 will over heat sometimes at high speed when it is very hot out. The solution is to drop down a gear and run at full throttle to move the coolant around faster.

 

 Both of these comments are just food for though.

Edited by Roger Walling (see edit history)
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I am not a mechanic, but a DIY car guy. When I had the head off my 1931 Chrysler CD8 (240CI), I also popped out the original frost lugs in the block so I could thoroughly clear out any crud accumulated over the 90 years. These Chrysler blocks had an early history of overheating in the 6/7/8 cyl areas due to inadequate circulation, and being so far from the rad. There was a lot of crud, in some cases passageways were reduced to very small openings, and much of the crud had solidified, so even a normal flushing operation would not likely clear it out. I poked and brushed, using a variety of tools, wires and even magnets, and with access thru the frost plugs outlets, and various other cooling posts, got perhaps 95% of it and then pressure flushed any remaining. I did similar exercise with head although it is much less complicated.

 

So you need to be aware of the possible buildup of crud in the block/head, reducing circulation, especially at the back of the engine. If you have access to someone with a heat detection device (one of those with a screen that shows different temps across the block end to end), you may be able to run engine up to operating temperature and identify where in the engine the source of the overheating is occurring. There are likely business that can give the block/head/system a good pressure flush without removing frost plugs (avoid doing rad at same time to avoid plugging the rad up) with products that can dissolve some of the crud. Good luck. BTW, fine looking car. 

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I think the system is working properly. If the car has thermostat controlled shutters it will not have internal thermostats. The shutter system is common in lots of big 30's Classics. Cadillac has them and I think senior Packards do too. They came in 160 & 180 degree rating and as you describe it , it appears to be hovering around 180 degrees. I think the theory is you install 180 if you are in colder northern climate and 160 in hotter southern climate.   10 - 20 degree surge when you slow down from a fast run is not unusual because the shutters may have been partly closed at speed due to the wind blowing thru the radiator and these mechanical shutters are slower than internal thermos to react to a change in temp. As long as it recovers back to about 180 in a reasonable time you are OK. Some fluctuation is normal due to the slower action of the shutters. Make sure the shutters are working freely but your description sounds normal to me. Water boils at 212 and it won't damage the engine at that temp but it will cause a mess. A 50/50 antifreeze solution will boost the boiling point about 10 more degrees and also improves heat transfer. Modern cars have pressurized systems and typically operate at 200-220  degres and don't boil over because of the pressurization. The only way you can tell the thermostat rating by the "160 or 180" stamped on the back of the unit.

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Quoted from my Cadillac Shop manual for:

 

Standard Thermostat

      starts to open 134-142 degrees

      fully open       154 degrees

 

High Thermostat 

       Starts to open   156-164 degrees

        fully open   176  degrees.

 

The standard Stat listed for LaSalle fully opens at 170 and higher stat opens at 185

 

I think his car is operating fine with the higher temp stat.

Chryslerman - Do you have a shop manual you can check yours to see what your states are rated.

 

 

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jdome……are those mid 30’s numbers? Early Cadillac & LaSalles and the V-16 run lower numbers than you are quoting……..His Chrysler is a 31……thanks. 

Edited by edinmass (see edit history)
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Hi Everyone,

 

Thank you very much for all the information you have provided i will take all your comments to my mechanic but provides me as a no mechanic a better understanding.

 

We are going  to take the side plates off  the engine on Friday to check if there is any restriction, interesting Roger sated ave a water tube that distributes the water rearward and sends it between the cylinders. It commonly has to be replaced we can check but does anyone know if this should be in there ?

 

We have had the pump out and overhauled when we recorded the radiator and it was also clear behind the pump in the block which i am  told were it can building restrictions.

 

My mechanic and rebuilder of the radiator is also saying the water maybe be pumping to fast and not having enough time to cool down which a lot has mentioned too and certainly going to look at too.

 

When we had the radiator out for repaired we check the hoses / pipes to the radiator all good 

 

When we had to remove the head due to removing  asbestos when i brought it into the country it was check and appeared clear at  the time i am  told by mechanic.

 

We are ruining a 50/50 antifreeze solution in the car  

 

I had to install a new temperature probe( old one broke off) so had a new one recalibrated to the gauge so i trust the readings when running the car it was about 13C or 56F so not a hot day 

 

Once again  that you all it is greatly appreciated happy motoring to you all, I hope to  have this babe running well on  the Australian roads, i hope to take it to Wangaratta late September as the Chrysler Nationals for 1 weeks are in Victoria this year i am  sure it will attached some attached hopefully for the right reason.

 

 

IMG_8830.JPG

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23 minutes ago, Chryslerman1929 said:

We are going  to take the side plates off  the engine on Friday to check if there is any restriction, interesting Roger sated ave a water tube that distributes the water rearward and sends it between the cylinders. It commonly has to be replaced we can check but does anyone know if this should be in there ?

On many cars of that age with a long pressed steel water jacket cover, these covers had a second inner layer of steel with water diverters aimed to force water between the cylinders.  These water diverter plates must have rusted away back when they were just older used cars, because the Dorman Company made new aftermarket ones to fit many different early cars back then.  

 

By the mid 30s many cars went way from the side covers and the block was cast without an opening for the cover (to save money?) These newer engines are likely were when a water tube was invented.

 

your car looks high end restored so I would think that the engine rebuilder would have made sure the deflectors were still there, if your car even had them when new, on it's water jacket cover.  I don't know if your engine had them or not, I'm just adding some info.

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1 hour ago, Chryslerman1929 said:

Hi Everyone,

 

Thank you very much for all the information you have provided i will take all your comments to my mechanic but provides me as a no mechanic a better understanding.

 

We are going  to take the side plates off  the engine on Friday to check if there is any restriction, interesting Roger sated ave a water tube that distributes the water rearward and sends it between the cylinders. It commonly has to be replaced we can check but does anyone know if this should be in there ?

 

We have had the pump out and overhauled when we recorded the radiator and it was also clear behind the pump in the block which i am  told were it can building restrictions.

 

My mechanic and rebuilder of the radiator is also saying the water maybe be pumping to fast and not having enough time to cool down which a lot has mentioned too and certainly going to look at too.

 

When we had the radiator out for repaired we check the hoses / pipes to the radiator all good 

 

When we had to remove the head due to removing  asbestos when i brought it into the country it was check and appeared clear at  the time i am  told by mechanic.

 

We are ruining a 50/50 antifreeze solution in the car  

 

I had to install a new temperature probe( old one broke off) so had a new one recalibrated to the gauge so i trust the readings when running the car it was about 13C or 56F so not a hot day 

 

Once again  that you all it is greatly appreciated happy motoring to you all, I hope to  have this babe running well on  the Australian roads, i hope to take it to Wangaratta late September as the Chrysler Nationals for 1 weeks are in Victoria this year i am  sure it will attached some attached hopefully for the right reason.

 

 

IMG_8830.JPG

I do not believe your engine has the water distribution tube. They came later.

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The numbers I gave you are out of my 36 manual but it is the same for 34-37  V8, 12 & 16 and same part # in parts book.

My Cadillac parts book shows a different PN for 31-33 but I don't have any specs on that one handy.

Cadillac used these thermostat controlled shutters up thru 41. Below are some photos of what NOS stats look like in their NOS Boxes.  These were made by Lylphon for Cadillac. I have some others made by Dole in Dole boxes. ......  NO, Don't ask!

I think Lincoln K used the same one as well as Chrysler and several more. I am only aware of the 160 and 180 degree versions but there could be a 140 version but I am not aware of 140 and don't have any specs for 140. 

 

The OP Chrysler may require 140 stat but the car acts like it has a 180 in it now. I can't read what it says below the 180 mark on the Chrysler water gauge but if it says "Normal" than I would say 180 is the correct stat.

 

IMG_20220802_214349202_MP.jpg.28ace2cfb7e4c7b71d47939d07c1eb1f.jpgIMG_20220802_214403870.jpg.df8ff7b5003c29305603169e77ebdd71.jpg

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