Head versus manifold coolant temps

[WFarm]

When I installed my new radiator and electric fans, I installed the fan temp switch (190 F turn on) in the left side head. The coolant temperature sensor is installed in the intake manifold and was not touched. Normal coolant temps run right around 190 F. and can be monitored via the Dakota Digital dash.

Since I also installed a dash mounted indicator light that lights up when the fans are energized I can see at what coolant temperature this occurs. Seems the fans are coming on when the temperature gauge is reading only 153 F. I read that the coolant temps in the head will run maybe 10-15 degrees higher than the manifold temps, but this 37 deg delta seems high.

Is this much of a temperature delta between the cylinder head and intake manifold locations unusual? Wondering if I have a bad temperature switch or if I should relocate it.

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[fast 99]

Had a mechanical sender in the head on a 350. Averaged 10-15 degrees hotter than the stat. In other words with a 190 stat head was around 205. I would assume a BB would do the same but how much of a split? don't know.

 

[PrairieDrifter]

My Dakota digitals read about 220 in the back of the passenger side head with a 195 thermostat. Just got used to it reading a little higher, I may change the location someday but it doesn't bother me.

 

[carnutjw]

My '87 Suburban-87(?) 454 w/ Holley Sniper setup, cast iron intake, Sniper ECT sensor in passenger head- shows 208-212 on the Holley handheld running down the road in warm weather and higher as soon as I shut it off or get in traffic. The factory gauge never gets near the 210 mark. My assumption is that the Holley sensor is maybe more accurate/sensitive and being between two exhaust ports it gets some heat conduction from them. Can't tell you what the intake temp is off hand, but it is on the handheld too and I know it is significantly lower than 210.