Overheating

[Canyon Man]

Ok, so I put in a new thermostsat and it is still the same but at least now I can give more details. I hooked up my computer to the truck and the temp gauge reads 259 deg f. The upper radiator hose reads 130 and the lower 85 deg. I am waiting on my water pump,should be in tomorrow. I think it may be the water pump....Any thoughts?

 

[Bedrck47]

Thanks a lot guys. I will check it all out this weekend. But I did change the pump and thermostat about 2 years ago

As I posted earlier A lot can happen in two years.

From the temp readings you posted sounds like your on the right track.

After you change the pump kindly take the temp reading again and post them. May be good information for the next person

 

[IMINYOURCHAIR]

+1 on the water pump. see if you can get some pictures of the impeller too if it turns out to be the culprit.

 

[Canyon Man]

Sure thing guys. Anything to help out the next guy. My water pump just came in. I will be starting this in a few

 

[Canyon Man]

Well all done but I had to drain all the anti freeze. So I filled it up, 2 gallons, started it up and within a few seconds...30..it was overheating.I have been adding more coolant as the reservoir allows. I figured since I drained it all, there is no coolant yet in the heads. So I am going to wait an hour or so and give it a shot again. BUT... I don't think the pump was my problem. The pump I removed was nice and tight, no play in the bearing and spun nice and smooth. But I will know in a few hours one way or another. Maybe the radiator is plugged. Don't know yet...............

 

[stamp11127]

What are you using for coolant?
What was the blocks condition when you pulled the pump?
How soft is the lower rad hose?
Did you bleed the air out of the system?

 

[Canyon Man]

What are you using for coolant?
What was the blocks condition when you pulled the pump?
How soft is the lower rad hose?
Did you bleed the air out of the system?

50/50
looked fine
very soft...no pressure
best I could.. parked on incline and left cap off . but it only runs for less than 30 seconds and goes into hitemp mode. Even now 2 hrs later I just turn the key and the temp gauge immediately pegs out to High with out even starting it. And when I did start it it went to hi-temp mode in 10 seconds after being off for 2 hours. I even disconnected the battery for 20 min thinking that might have something to do with it but nothing.

 

[stamp11127]

Which engine do you have?

The 5.4 has a cylinder head temp sensor that doesn't show being on the 4.6 according to the diagrams. I would verify the engine coolant temp sensor or cylinder head temp sensor is operating correctly.

If you have an IR Temp gun I would take readings of the heads, rad hoses and across the radiator.

I doubt this is your problem but hoses shouldn't be soft but firm to the touch. Under some circumstances the water pump can collapse the lower rad hose cutting off the flow of coolant.

You didn't state seeing bubbles in the overflow tank while running so I'll assume you haven't blown a head gasket.

 

[Canyon Man]

It's a 5.4. I know what you mean with the hoses but that's not the problem. It would have been an easy fix. I have been working on this for 10 hrs today...Time to walk away, regroup,relax,get liquored up and hit it again tomorrow. The sensor you are talking about is located under the intake manifold. So that may be another thing to check out.This is quite perplexing though. Nothing like a challenge

 

[Bedrck47]

not to insult you. But are you sure the t/stat is installed properly?
also have you tried running it without the t/stat and checking the hoses