Re: 1954 Packard Pacific 359 L8 radiator / rad cap / 7 / 12 / 13 psi

Posted by HH56 On 2020/12/1 19:51:06

The thermostat is probably a capsule type as Packard switched to them exclusively in 54. I don't know if Napa sells a 12 psi cap so that might be the reason others have crossed to the 13. Packard also has a bit of ambiguity because in the parts book they mention a 13 as the high pressure option while the service articles refer to it as a 12.

Several run 160 degree thermostats so the water can start circulating a bit sooner to give a bit more room before overheating could become an issue. If your car is not overheating then your 180 should be fine and the higher temp should give more for the heater to work with in the winter.

I cannot explain why a rad leak is seen at 7 but not 13 either. Logically it would be the other way around but seeing any leak at all and I think your radiator may be on borrowed time. Some say aluminum cools better and others say copper is still the standard. I do not know which is best but several have had a place in Alabama make custom aluminum radiators. They have them for some 30s models but nothing later than 48 postwar. Price seems fairly comparable with a copper recore using original tanks and mounts being in the 6-700 range while custom aluminum including new tanks and mounts etc is a bit more.