1950 Desoto-correct radiator cap pressure

What is the correct radiator cap pressure to run on my 50 Desoto? I bought one from a local parts store that is 4lbs but not sure if that is the correct one or not.

Thanks in advance,

Matt

Your car should be run at as low of pressure as you can . Especially if you have the original honey comb radiator. I run mine at zero to save the cores on all my 40's Mopars.

In 1950 or 51 was the 1st year of pressure @ 4 lbs for your car though.

Your car should be run at as low of pressure as you can . Especially if you have the original honey comb radiator. I run mine at zero to save the cores on all my 40's Mopars.

In 1950 or 51 was the 1st year of pressure @ 4 lbs for your car though.

Thank you, just what I needed. I replaced the water pump, thermostat, all hoses and flushed the radiator. At idle and warm it is just over to the right of "mid". I haven't driven it in any kind of heat yet but want to make sure I have everything sorted out before the heat is on.