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So there are two clearances I need to be concerned about. #1 is the impeller to the p[ump body and #2 is the impeller to the back of the water pump cavity in the block. I'm using the repo gasket from Max Merritt.

I'm actually in the beginning of process of checking measurements and I'm draining the cooling system with the goal of measuring the clearances this week.

I measured the clearance of the impleller to the pump body and it's at least .060. Using modeling clay, I measured the distance from the impeller to the block and it's .050.

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One thing that could help would be to check that there are not too many gaps around the radiator and the radiator frame. You want as much air that comes into the grill to be forced to go through the radiator. If there are gaps around the radiator and radiator frame, the air will go around the radiator rather than through taking the path of least resistance.
Think of it kind of like the function of a fan shroud, but on the bumper side of the radiator.

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Speaking of a fan shroud: V-8 Packards don't have one, of course. I am finishing constructing one for the Panther which has an oversize 4-core radiator and an A/C condenser in front of that. Pictures, explanation and P/Ns in about a week in a separate thread for those who are interested.

Craig

No gaps for air to sneak by. Water pump is suspect as little water flow is observed with radiator cap up. This is a non pressurized with no thermostat in line. The front grill shutters act as a thermostat.

I was hoping someone with a 32 era car could verify if they see water flow when the radiator cap is off.

When I look into the radiator, I cannot tell if coolant is flowing or not. While I haven't driven the car much as it is still being restored, I don't think that I have a cooling issue.

I spoke with Wade, owner of the Flying Dutchman water pump rebuilding service in Selma, OR. He seemed to know his stuff and describe exactly what my water pump should look like. He said the critical dimension were from the impeller blades to the water pump housing. .60 he said was pushing it as it should be .010 to .030. His belief is that you should see coolant circulating especially when you rev up the engine.

His plan is to replace the 4 blade impeller with a 6 bladed impeller from a John Deere tractor water pump. He said he's had good success with this mod. He will also turn the base of the water pump and also the impeller blades so there is an even gap between the impeller blades and the pump housing aiming to get a gap of .010.

10 day turnaround he said.

Packard was obsessed with making certain their cooling systems were more than adequate for the task.

The problem is what time does to radiator internals.

Yes - "rodding" does help a little. The real problem is the inevitable "build-up" on the inside walls of the radiator cooling tubes. No "rodding" or chemical cleaning process can resolve what time and chemistry does to those tubes.

By the World War One years, Packard had a well-deserved reputation for delivering a superior product. Getting that superiority back means recognizing the basics of chemistry and physics.

Bottom line - if the radiator is more than 30 years old, remove it and send it to a competent radiator shop. They will order you a suitable modern "core", put your old "top" and "bottom" tanks on it; then and only then will your car deliver the cooling performance it did when in service as a new car.

I presume you already know about cleaning out the left side of the engine block - easily accessible by removing that long "cover-plate".

Radiator has been recored and rechecked. The engine was completely rebuilt. I removed the left side cover plate last week when I removed the water pump just to make sure. It was clean.

The initial feedback from the rebuilder was the impeller was too far away from the body plus the body of the pump had a lot of pitting which could cause other issues.

He also wasn't too thrilled with the rebuilding job done previously.

Ken

The impeller-to-pump body clearance should be somewhere between 0.010" and 0.030". If you have more than 0.060" clearance I think it's a safe assumption that your pump's volumetric capacity has been severely curtained, perhaps by 50%, maybe even more.

For whatever it's worth here's a pix from my spare 11th Series water pump. The impeller is the original cast steel and it's just painted with RustOleum as it's in long term storage. The clearance at the outer impeller tips is about 0.037" and at the inner root just a tad less than 0.020".

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