Packard Forum Index » Pre-War (1899-1942)

Was reading the 1938/1939 Packard Six Shop Manual, and noticed the engine numbering conventions on page 3. It is stated that '38s have engine numbers starting with an "A", and '39s start with "B". The Packard engine (L head straight 6) in my 1939 Six Business Coupe carries an engine number starting with the number 2 and ending with an "A", which seems to defy the numbering convention. Perhaps the engine was swapped some time in the past, or is the car actually a 1938 model? Are there any distinguishing features that would clearly identify the car as a '39? Anyone else notice the engine number format on their Packard(s) not following what the shop manual indicates?

If you take the engine number and plug it into the Engine Section in the Decoder here on the website, it should tell you what it was originally from.

If it doesn't decode, take a picture of it and show us. Sometimes the number stamping can be hard to read and often B and 8 and other letters and number are often misread.

I find rubbing the number with a piece of chalk and then wiping it off will make it easier to read.

The VIN itself should tell you but if 1938, it would have a floor shift and there would be a little piece of trim running up onto the roof above the center divider. More likely yours was a dealer replacement which often came unstamped, they we’re stamped by the dealer.

The VIN decodes to a '39 Six, so that is good. The engine number - 23870-A - decodes to a 1927 8 cylinder car, the 3rd series as Packard calls it. The mystery continues.






Thanks for the help.

To add to my uncertainty as to what year the engine in my Six is, I just read in the 1938/1939 Shop Manual on page 10, section 12: Engine Notes, there is a notation -- All engines with A suffix to engine number have cast alloy iron camshafts; with B suffix, forged steel. So, there appears to be precedent to Packard using engine numbers that are different than what the manual indicates on page 3. The reason I want to be sure about the engine, is I am facing troubleshooting an engine overheating problem, and wish to know all I can about that part of the cooling system. The shop manual is a little light on detail - section 16 and 17 - about the thermostat, which, if I am reading this right, is actually located in the upper radiator tank. There is no temperature reference number stamped on the face of the shutter linkage device on my radiator. Any insight would be greatly appreciated.

You could check the casting date which should be located towards the rear on both sides of the lower part of the block

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Note that you could have two thermostats. You could have the one in the top of the radiator tank as you mentioned, which would have been standard equipment in 1938 and operates the grille louvers. So, that one controls air flow to the radiator. You could also have a thermostat in the cylinder head which controls coolant flow through the system. . These were often added in the winter time to improve heater performance. The service manual, though, says to remove the cylinder head thermostat in the summer time.

If someone ever installed a cylinder head thermostat, it is a possible source of restriction for the coolant.

The Sylphon grille thermostat was also standard on 1939 models as my original Six had it. For 1941, it was standard only on the 160, 180 and Henney-Packards.