TF running hotter on highway than in-town.

[roger55]

Anyone else experienced this?

I'm trying to figure out what is going on and what to do about it.

I've got a 305 TPI engine with a 180 Stant thermostat that I can verify that it does open at 180.

The radiator is a new American Eagle (Champion)with 2 -1" cores and an internal tranny cooler and is advertised to cool up to 650HP
It has a 16" Maradyne electric fan mounted to a shroud covering 100% of the core. The fan switch turns the fan on at 190 and I've verified that. The differential is low though and it will cycle it off after cooling only about 1 degree.

I've sealed around the radiator and condenser well so air entering the grille area cannot go over the top or around the sides.

The truck has Vintage Air A/C and all the testing I've done is with it turned on and the ambient temperature at 95 degrees.
After some extended in-town driving, the water temperature runs at 192-196. Getting on the highway and running at 65MPH (2000 rpm), it will warm up to 210 after about 10 miles. I Transitioning back to in-town driving, the temperature will come back down to 192-196.

These aren't damaging temperatures but what concerns me is a hotter day maybe up to 106-110 and pulling a highway grade. With what I've got, I have no room for the extra heat those things would do.

Here's some photos of my setup and how I sealed it:

During initial mockup with a good angle to see the shroud and fan:


During final assembly:


Foam seal and tape to insure air coming thru the grille can't go over or around the condenser/radiator:



Underneath side. Another seal between lower radiator tank and the splash pan:


Header panel back on.


Here is a snapshot output from my ECM running at 65 MPH. Note: The speed is wrong in my ECM and the temperature shows 196 because I had just got on the highway and it hadn't warmed up from there yet. The mixture says lean but it alternates back and forth from lean to rich constantly. I believe that's what it's supposed to do.
And btw, my dash temperature gauge is right on the money with what the ECM reports.