Overheating 2006 2.7

Doesn't overheat at idle, ran for an hour
This has been a headache to nail down
Within 10 minutes of driving overheating occurs with the overflow cap popping and coolant boils out. Often the gauge hasn't moved beyond mid/normal. Does the sensor play an active role in cooling?
Heat works until boiling starts
Fan runs when warmed up. (Stopped until warmFan and fan clutch had an oil coating. Going to replace.
Thermostat had damage to rubber seal, possibly preventing it from opening. Replaced and seated 12 o'clock. Block test negative. NormL clean coolant. Expert buroer
Water pump has no issues, removed and reinstalled

Going to replace hoses and heater pipe, since it's getting torn apart.

1/ Will check radiator for flow. It could be obstructed from the old thermostat gasket, IDK. Do they just get obstructed from use ? Presume the hot coolant enters the lower hose and exits the top to the engine.

2/ May try running it without a Thermostat

3/ Fan Clutch Assembly possibly bad ? It engages and spins when warm. Is there more to it ? There was oil on the fan blades and baked onto the clutch.
This truck has over 300k on it, but the engine runs smoothly and gets better than EPA gas mileage. All the pulleys and belt turning items are in good shape or replaced. No Leaks or strange noises

Suggestions ? Thanks

 

Does it have enough coolant in it? Did you burp the system? If I recall the temp sensor is up high on these trucks, if its low on coolant it wont read an overheat correctly.

Mechanical fans should always be spinning. But they should have low resistance when cool. A rolled up newspaper should be able to stop it turning when cold. As they warm up the viscous clutch engages more and more. That said, fans dont add much cooling on the road at speed

 

Shoot, I just read you have the 4cyl 2.7L. Idk where the temp sensor is on those so my post above might be off

 

Do a chemical block test to check for a blown headgasket

 

Block test negative. Coolant smells like new, because it is. But no gas or oil or even dirt

 

It's fully burpest.
I learned there won't be heat if it's not completely topped off

 

It doesn't turn when cold.
Starts spinning about when the thermostat opens.
In general, of the vents has heat, the fan is running

 

It's turning out to be a bad radiator cap. It just fell apart when I removed it.

Of course now it makes sense why it boiled out through the overflow

Ordered a Gates cap, arriving tomorrow

Thanks Everyone

 

That's a lot of work you put in there but it will pay off with all of that taken care of.

I'm hoping that by "heater pipe" you meant the coolant bypass pipe that runs under the intake manifold. It's a bear to replace the original plastic pipe and it's hard to believe yours has lasted 300K miles. Regardless, if you haven't already done so, replace it with a new style metal (or even stainless) bypass pipe.

Good job getting it sorted out!

 

It's turning out to be a bad radiator cap. It just fell apart when I removed it.

Of course now it makes sense why it boiled out through the overflow

Ordered a Gates cap

Thanks Everyone

 

I'm hoping that by "heater pipe" you meant the coolant bypass pipe that runs under the intake manifold. It's a bear to replace the original plastic pipe and it's hard to believe yours has lasted 300K miles. Regardless, if you haven't already done so, replace it with a new style metal (or even stainless) bypass pipe.
I got a Dorman 626-554 bypass pipe from Walmart for $20
Upper and lower Gates hoses from Home Depot. $22
Heater hoses Gates (3) Amazon, but delivery was not as quoted. Still waiting. Should have gotten them from Home Depot.
I tested all the Thermostats with hot water, ended up changing to a Gates, as it opened faster and wider than the others. My original wouldn't open.

The radiator cap appears original. I got a Gates from Amazon overnight.

Going to wait on the bypass pipe and heater hoses, since I need to use the truck and still awaiting parts.
Everything is working correctly and it's fully burped.
I'll post separately on the bypass pipe and heater hose.
New hoses don't get soft when heated up, as the old ones.
Drove it nearly for an hour, engine constantly running for two hours. Seems good so far.