So it holds all most 2 gallons in the system still?

 

I have the same issue on my 2003 supercrew 4.6. Temp gauge barely moves after running for an hour in the driveway. Held the revs at 3000 for 10 minutes same results. No cabin heat and no temp in the motor. Top radiator hose has minimal pressure

 

Bump

 

Okay so I found out that one of the temperature sensors is in the same electrical circuit as the oil sending unit. Since the oil light comes on when my temperature gauge pegs hot could it be causing the temperature readings to be messed up if the sending unit was bad?

 

Well after changing both temperature sensors I found out its probably not an electrical problem. So I talked to my mechanic and he said it could be a blocked radiator or another thermostat because when I flushed the truck out the antifreeze was brown the overflow was caked in dirt on the inside so theres probably still a lot of dirt in there which is either blocking the radiator or just too much dirt flowing around which is screwing up my thermostats. So it looks like shes coming apart I'll post up when I'm done if it was my radiator. -Zach

 

Anything?

 

any updates?

 

The ETC is an absolute pain in the ***. It is located under the intake manifold and is what sends the information to the thermostat. If you are older than 6 years old you will need to remove the intake manifold in order to access the sensor. The sensor itself is only about $25 at autozone, but it is a rather tedious chore. If you have changed the thermostat and flushed already this is something I highly suggest doing! My 05 (210k) threw half a dozen codes which threw me off, but if not taken care of it can cause stalling, surging and banking while driving and even shaking similar to a mild misfire. The task it self is straight forward but getting to the work area is a pain. I suggest clearing an entire day to handle it or take it in to the dealership and pay $800-$1200 for the same job. For pics or a walk through hit me up I’d be glad to help!

 

Time to start over again, your out in the weeds.
1. Filling is critical or you get air lock. The Heater is the highest point in the system. Don't have to race the motor.
2. After filling, run the motor long enough to 'normally' fully heat it, even with the CAP off to see air bubbles being purged from the system.
3. Put your hand on the top hose and feel it get hotter (if - and when) the Thermostat [[opens]]. A check on the Thermostat function.
4. Nothing tells the Thermostat to open but the temperature of the coolant. The motor is generating heat of combustion, coolant flow or not. Remember this. Water pump moves the coolant in the system. Is it internally faulty as a last indication?
5. Is the Thermostat installed backwards? Does the Thermostat have a small bleed hole in the rim area to help air bleeding?
6. If there is no circulation, the motor will overheat! This is even true in the winter if the radiator freezes from lack of Anti Freeze mix.
7. The Transmission has a sensor to disallow OD unless the Trans fluid gets up to near 100 degrees, that's normal while driving.
The fluid passes through the internal radiator Cooler, on the driver side.
8. The [Coolant sensor] does not control the cooling system in any way. It signals to the computer what to do with fuel, Ignition timing and control of the IAC for high idle. Too cold and the motor runs RICH is normal result and affects fuel mileage.
9. There is an intake air temp sensor as well to help control/signal cold starts and drivability after the system is up to temp.
If the radiator is blocked, the motor will over heat >>and no heat from the heater because there would be no coolant flow.
If you were to check with a Scanner, a code may show for the failure of the system to heat up in a certain amount of time determined by a computer timer function.
The actual temperature could also be read by the Scanner.
The dash gauge could be faulty even in a normal cooling system as a side issue.
Another issue can be the fan Clutch is not releasing the fan. You can test this by using an old fashion timing light on any cylinder and pointing it at the fan blades. You would see blades change speed as the Clutch normally responds to the Thermostat open and closing detected by the heat from the radiator..
Review all the above, it's just most all common sense for heat production and cooling.
Good luck.