Hi everyone

I have a 2002 Supercrew, 4.6L Triton that is bone stock except I have put in a Visteon Dual Core radiator. The truck runs perfectly. I don't haul anything yet, but I often have it loaded up to near max payload capacity. I live in Texas and often drive in 90 + degree temps. I'm preparing to add transmission cooling and a drop hitch because I expect to be towing a utility/farm trailer soon.

So, I started collecting information on how the truck actually performs, just to see what i had to pick the right mods. I hooked up an Actron ODBII scanner, the good one that collects and displays engine operating parameters to see what the actual engine coolant temp was being reported as. On the highway, hauling about 1400 lbs of payload at 78 degrees it was reporting 172 degrees. The idiot light...er...gauge was acting as it always does...pretty much in the center of the temperature range. So, what's up with that. That temp should be 200 degrees plus...probably higher. Any thoughts...or am I just overthinking this whole issue?

 

2 core radiator.. 2 times the cooling capacity.

 

I'm with you on the radiator. But....that temperature is below the thermostat's control range. I believe that these trucks all come from the factory with a 190 degree thermostat. The thermostat controls the low temperature of the engine.
Under normal conditions, the lowest temp at that sensor on a normally operating engine should match the thermostat. Since that sensor is near the engine coolant outlet, the coolant should be at it's warmest temperture.

There's no indications of a stuck thermostat. It warms up just fine. On the scanner, the temp climbs steadily up to that 172 degree reading and just stops.
It does go up a little with the a/c on, or sitting in traffic. But not to 190. Just to check the scanner, i put it on my wife's cougar...4.6l engine and it showed 198. So i think the scanner is fine.

I'm good with the cooler temps, but I would like to be able to explain them

 

Are you the original owner of the truck? If not maybe the thremostat was changed before you purchased it. Unless you have a faulty temp sensor that the scan tool is getting it's data from. If not I would think it's gotta be the thermostat...

Shane

 

Yep. I'm the original owner. I think you've hit the only 2 "failure" modes that explain this...a stuck thermostat or a bad sensor.

 

The OBDII temperature comes from the CHT (Cylinder Head Temperature Sensor. There is no ECT (Engine Coolant Temp) sensor on it.

To get an independent reading of the operating temp, use a non-contact IR thermometer and measure the temp of the thermostat outlet housing.

Steve

 

I have the same truck and engine.
First, the temp gage will not register the temp rise as you would expect because is is not a direct fully indicating and sensor driven circuit.
My temp indication follows closely and within +/- about 2° of the thermostat 200° value depending on the load and ambient, as monitored by a tuner with this ability.
The radiator is a two row and with fan cooled transmission cooler.
Normal temp for the converter output and unloaded running is 148°, with deep pan and custom built towing trans.
I pull as high as 12,000 gross weights.