Topic: Does anyone know know what an acceptable radiator temp drop is

[Blues Power]

Using an infra red gun after a 20 mile drive on an 87 degree day with high humidity

with car idling, I zapped my rad upper fitting and got 189 deg F.  I got 159 on the lower, give or take a few 10ths

is 30 degree drop acceptable?

(the stat im using is 195)

[carlite65]

those #'s sound fine to me. enjoy the ride!

[RoyceP]

A really cool running engine too. If the temp gage is pegged or close to it with those numbers 1st thing to suspect is the sending unit. Properly working sending units don't come from auto parts stores or Scott Drake.

[1967FEGT]

Yes, that sounds in range.  I think most of us run a thermostat in the 180 area. Yes, buying a Motorcraft or Autolite service replacement will set you back 60-100 but the gauge will read correctly.  Not one of us has found an aftermarket sender that doesn't show the engine as hot or borderline at operating temperature.

[Murf]

A drop of at least twenty degrees F. is normally the accepted figure for a healthy and properly cooling radiator with temps measured at inlet and water outlet.