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

just behind the waterpump is the water distribution tube.It is made of brass and imbedded in the engine block.It has a series of holes of different diameters that meter the water flow to each cylinder.They can get clogged easily. Pull out the tube an clean it as well as the cavity in which it sits.Like you,my 1949 288 was running hot .this solved the problem.You can also modify and replumb the heater core to turn it into an auxiliry radiator.

Speaking of heater core, if your has been bypassed that can also cause overheating.

Check it with an external temperature meter . Are you loosing power ?
Check the Vacum is it working ?

Hi not a mechanic here and have a 51 300 where I used to go nuts because the temp gauge was always between the middle and the "H" reading I attached this service letter whichI found on this site which kind of removed some of the anxiety for me maybe it will help. (I have never boiled over)

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I had a very similar problem with my 36 Packard and I ran a borescope into the radiator tank and found several tubes blocked or almost blocked. It seemed to flow good during the previous flush.

Update: I got 5 gallons of Evaro-rust today and put all of it in the cooling system (100%). After 2 drives I can't get the temperature gage to 180 deg f. It did to go to 220 deg. F. I am going to leave it in for a few weeks. I think it will get better. You might want to try Evaro-rust if you tried everything else like timing etc. It's about $120 on eBay.

Quote:

What did you base “It seemed to flow good” on?
The radiator gravity flow rates for 36, per the service manual, are
Eight: 30 gallons per minute (GPM)
Super Eight: 30 GPM
Twelve: 50 GPM
One-Twenty: 22.6 GPM
One-Twenty B: 25.8 GPM

Your right I did not base good flow on the actual specification. I didn't set up a flow bench. I just flushed it, and it seemed to flow good, but actually wasn't. I guess that's my point: they can fool you unless you measure it.
Correction: I spelled it wrong Evapo-rust