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

According to the parts xref these are modern thermostats that will fit that you may be able to find over there. If the links will work, they cross to current Napa numbers:

https://www.napaonline.com/en/p/MRDPM1800025?interchange=1

https://www.napaonline.com/en/p/MRD70?interchange=1

Different temperatures and both have a flange diameter of a little over 2.1 inches.

Be careful on the new radiator caps. Packard until 1955 used what is called a long reach cap. If the radiator is still original type, the sealing surface in the radiator opening is lower down than modern radiators so the spring and rubber sealing washer on the cap that goes against the surface needs to be longer. I don't remember the exact difference to a modern cap but believe it is something like 1/2 inch. The shorter spring standard reach caps will not be able to seal.

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For what it is worth-I have been running my 47 Clipper without a thermostat for about 2 yrs-with no problems. This came about after putting in a new thermos and to make a long story short-found after many issues with overheating-the thermos was intermittent. Just took it out. Temp with get up almost to mid point on hot days.

this might be an option in your southern state, but my only hope is global warming... its quite cold here and my engine should not run cold for a long time. The thermostat was made to minimize the warming up time.

If you have issues with overheating the first suspect is the radiator. American cooling systems do not close the direct way to the water pump when opening the way to the radiator (compare double thermostat of the Mercedes shown above). The water takes the easiest way and if the radiator is only a bit dirty inside, the water will not pass it and take the direkt way.

Running without a thermostat will cause the car to run at a low temperature. This is not how a car is designed, it will cause a buildup of sludge in the engine because it does not warm up enough to evaporate the condensation in the crankcase.

If the car overheats with a thermostat replace it, if it still overheats your problem is elsewhere.

Also if too much water flow then heat transfer is lost. We had a hyd. pump with a malfunctioning temperature control and one of the guys thought that he could just open it up and let max water flow to cool the system down. I show him that the water exiting the cooler was the same temp as the water going in. We set the flow until we the output of the cooler was staring to get hot and left it for the next crew to replace after training was done for the day.
I would said if it belongs on the car keep it on, it's normally there for a reason. Packard had good engineers working at making these the best cars out there.
Now I'll get off my soap box.
Wes

Good Evening Elefant...I also drive a 1949 288 Deluxe. I had heating problems and discovered after reading on this forum that I should run 50/50 coolant and should run a thermostat that runs about 141 degrees. It can be had from NAPA. It is part number 18-3551 -line SME. Our Miss Prudence now runs between 150 and 195 degrees, depending on what we are asking her to do. The biggest challenge is at long lights or traffic jams.

As well as cleaning out the water passages in the engine and the water distribution tube and making sure the water pump is working properly and your radiator is clean, make sure that your engine distributor is working properly and that the springs that adjust the timing have not grown week with age or are broken.

We also moved the vacuum tube pick up from the bottom of the carburetor to a port on the intake manifold. This change allows the vacuum to advance a bit sooner and so help her to stay cool. After these changes, our old girl runs great.

All folks have differing opinions, these are ours and they work for us.

We live in the hot southwest in Scottsdale, Arizona. If you live in cold country, you might just need to take the time to warm the engine up to operating temperature before you try to drive it. Or experiment with a 160 thermostat as well. They are not difficult to change. Good Luck, Ernie

today my MaxMerrit package arrived... what you get is not the original bellows thermostat but a normal modern one... with a nice cork seal, for 15,-$

It fits in the outlet with the retainer (+10,- $)