Packard Forum Index » Post-War (1946-54)

I have read in the Packard literature that there are four types of radiator cores that the 1948 and 49 cars used originally. They are (395244) for six cylinders and taxis, then the standard Eights (419500), the Super Eights (418785) and lastly the Custom 8 (389859). The Custom 8 radiator is a large, heavy version, significantly larger than that used in the Super 8s.

Recently, I had a radiator shop re-core my radiator. They used the larger, much thicker core.

Now I am trying to get the car back to the proper size radiator that it was originally supposed to have.

As a result, I need to know if anyone has the dimensions and specifications for the radiator core that goes into the 23rd series, 288 cu inch, standard 8 car? (I have been told by the parts suppliers that it is the 419500 core per above). I think the entire radiator is called the McCord E8-88 radiator.

I would like to obtain the original dimensions, number of columns, fin spacing and other specifications of the 419500 type of core so that I can get it back to original.

I can't help with the dimensions but am curious why the desire to go back. Is the larger core causing problems or not doing the job or is it just esthetics? Several have opted to increase core size for various reasons and to the best of my knowledge have had no issues.

Yes, there is an issue with the larger core. I am having problems with high engine temperature at idle but not at cruising speeds.

I have researched it and realize that now that I have more volume in the radiator, the fluid runs through it more slowly.

It is like a hose, if you pinch the end of it, the flow will go faster but if you open it up it will flow more slowly. And cooling is not as good at lower flow rates.

The cooling at low rpm's is not as good as it used to be when I had the standard core. And the spread between cooling performance at low rpm's and cruising speeds is much different than it used to be.

The radiator shop agrees that the fluid is running through the radiator slower but also tells me that since the radiator is larger, the coolant stays in the radiator longer so it should be cooling better. The problem with this reasoning is that you now need more airflow from the fan at lower rpms to make up for the slower fluid flow rate. (This fact about needing more air when you enlarge the radiator is well publicized on radiator performance sites). ButI am not interested in adding an auxiliary fan to the radiator.

I have had the engine rebuilt, added new water distribution tube, new water pump, 140 degree thermostat and all channels for the cooling redone. Everything is clean.

I even made sure that I always use a Ganno filter in the upper radiator hose to make sure no engine crud clogs the radiator. (I had this filter in place before the rebuild but still have it left in today).

So I wish to get back to the original core to improve the cooling at idle.

That is why I want the original specs for the original core.

The use of a 140 t-stat will result in a buildup of sludge in the oil pan due to condensation in it not evaporating. I suggest using a 180 and observe cooling abilities, an easy experiment.

When a car is equipped with A/C it gets a larger capacity/size radiator and when it runs at idle it does not heat up more.

Exactly what is the "problem" with cooling at idle?

Good afternoon Joe...I offer a couple of thoughts based on our 1949 Deluxe 288. Ours in like yours with a new radiator, aluminum in our case. It definitely helped but the final bit of the problem was the distributor. It was dirty inside and had weak springs so the advance was sluggish. Once we cleaned it up and put in new springs things improved again. Finally, we took the vacuum advance tube and moved it from the base of the carburetor and connected it to the intake manifold to give a bit more advance at long stop lights. The car is happy in any hot weather that I wish to drive it in. We live in Scottsdale, Arizona it does get hot here in the summer time. I don't like to drive without air conditioning when the temperature is 99 degrees or more. Our Packard is happy at this temperature. I have not tested it at 100 degrees plus because I don't like it. This is just my humble opinion but it might be worth checking out. Good Luck, Ernie

Fred,

Thank you.

These are good inputs. The problem with cooling at idle is as follows: After a few minutes of idling in most weather, the engine temperature begins to climb but I don't let it get above 220 degrees. Basically, the car does not hold at a steady state when idling. It is worse in warm weather.

In fact, on one day in the early spring after the radiator shop put the larger core in, it was a 35 degree morning and I let the car idle for about 20 minutes. The engine temperature climbed up to 220 degrees. But once I drove down the road, the cooling system worked so well that the thermostat had to close up to keep the engine above the 140 degree rating on the thermostat. So with the new radiator there is a much larger delta between cruising and idling cooling than before the radiator shop did the work. Now that the engine has been rebuilt and the addition of all new components for the cooling system, I believe there is nothing left except for the radiator.

The radiator shop suggested that I change the pitch of my cooling fan to increase the airflow through the fins. So I think they are admitting that we may need more airflow to get the larger core to work properly. (I could also add an electric fan backup but I should not have to do this)

I know that you are correct about the lower temperature thermostat and I believe exactly what you say about the sludge in the oil. So I would like to go to a higher value thermostat but the lower value seems to give us a little more of a head start at idle before the temperature begins to climb.

When the car is equipped with A/C, is the water pump or fan pitch any different? It would seem that there might be some difference in some of the components to compensate for the higher volume radiator.

I very much appreciate your inputs.

And I would still like to try to get the specs (number of columns, etc) on the original core so that I can understand the difference. If anyone has this, please send it.

Ernie,

Thank you. These are good inputs.

I am surprised you changed to aluminum since copper has much better thermal characteristics than aluminum (copper is twice as thermally conductive) so I would think that the original copper core would work better.

Your comments about the vacuum advance are very much appreciated and are definitely worth considering

Quote:

AC cars have a heavy duty fan. I believe the difference is the number of blades but there could also be a pitch and/or diameter difference.

The heavy duty fan was originally made for some prewar junior cars in situations where overheating at idle and slow speeds was an issue. Postwar they issued another bulletin to authorize use of the fan in more models for the same reason. We don't have the bulletin to know exactly which models Packard was concerned about to authorize the fan in them but prewar they were typically the junior models with the smaller radiators.

Howard,

Thank you. So the application of the heavier duty fan by Packard, I think is making the point that a larger radiator needs more air flow. (Based on the literature, this seems to compensate for the lower fluid flow rate)

I guess now the question is, do I live with the larger radiator and try to make it work by increasing the airflow? Or as a purist, do I try to get the car back to original and work towards better cooling at idle (by increasing the fluid flow with the smaller radiator).

One quick test that I can make is to slip a regular 110v fan in front of the radiator while it is idling to see how the cooling works with increased air flow. (Obviously, this won't be in place while the car is moving but it confirm the point about air flow at low rpm's.

In any case, I would like to know the specs (number of columns, etc) on the original core (the 419500) to see what I can do next. If anyone has access to this, I would appreciate having it.

The electric fan in front might be an interesting experiment. I know some have added radiator shrouds on the cars to make the original fans more efficient. On postwar AC cars, in addition to the heavy duty fan, they also used a thicker radiator having more cores. Prewar AC cars seemed to only need the larger fan.

I must confess to not totally following the slow water flow theory but then I am not that well versed on some things. I would think it just the opposite. Assuming the passages thru the cores are the same size and the only difference between the large and small radiator is more cores, It seems with the larger radiators there would be more channels so the flow thru would be faster. I could see with flow being faster, the water is passing thru so quickly the heat is not being extracted which I believe was a problem with some Ford models of that era.