Ok, so I have a 00 Excursion V10, 180,000 miles. Started overheating about a month ago, very sporatically. Would should up PAST the red, would put it in neutral and turn it off and restart the vehicle, temp would be right back to normal. Replaced the thermostat. Made sure fluid was good 50/50. Started happening again, so got a radiator and it happened AGAIN. Fluid levels were only about an inch below minimum on the reservoir. I am completely perplexed by what is wrong with this truck. Any help is appreciated.

 

Is it actually boiling over ??

 

I'd find a way to see if it really is overheating or if it's just the gauge. I'm assuming you're talking about the gauge on the dash?

Maybe get or find someone with a scangauge that you can hook up to it. One of the settings on there is water temp and another is cylinder head temp.

 

Ok, first off I am posting this for my husband. I know a little bit but he is working and I am trying to figure this out.

The only reason why I think it is boiling over is because of the missing fluid. I didn't see any fluid in the engine compartment when I got home and checked it just the inch or so of missing fluid. Before the changing of the radiator it would overheat and half of the reservoir would be missing. And the radiator was completely gunked up, that is why I am confused as to what is going on with it.

It is throwing that engine code that shuts off some ?valves? at the beginning we thought that sensor was what was wrong with it and we did go get it, just haven't installed it.

 

It was the cylinder head temperature sensor that we purchased.

 

So it was not really overheating ? it was a false guage reading ? yes ?

 

I am not sure if it is overheating or not. Before the radiator half of the reservoir would be gone after overheating. Got the sensor because we thought it was possibly faulty just because of the super fast cool down after shutting off and restarting.

Going to get a new thermostat(even though ours is only about 1-2 months old), wondering if it is possible there is a hose that is compressing--causing the quick cool down after shutting off.

Worried sick it is a head gasket.

 

You may have gotten a bad thermostat. Check it (if you want) by putting it in a pot of water, and bringing it to a boil. See if the thermo opens up. You could also have a hose collapsing, as stated. Could be that the thermostat was installed backwards.

 

A couple of possibilities but more information would be helpful.

Is it "overheating" at idle or in stop and go traffic or cruising on the highway or all of the above?

Does the temp guage move smoothly from cold to up past the red or is it "normal" for a while and then just shoot up?

When you pull the dip stick how does your oil look?

When you look in the coolant tank how does the antifreeze look?

With the coolant cap off start the truck and put your hand over the neck. Do you feel any pressure or suction?

 

Overheating 99.9% of the time is on the highway or going over 55 mph. NOT in stop and go traffic. It will be completely normal and then shoot up past the red, not even in the red anymore...check engine light will come on, oil light, and temp. light. Oil has been checked and perfectly normal, fresh oil. It's raining or I would go check the reservoir suction.

 

Odd...........So what all has been replaced again ??

 

Replaced the t-stat, upper hose, radiator. We are trying to MAKE it overheat. It won't while idling. Coolant is light green, just did the 50/50 yesterday when the radiator was changed. I filled it to minimum yesterday, today when I had it idling the levels were about an inch and a half above maximum. There was ONE stream of coolant from the radiator cap, but when I took off the cap you heard the whoosh and coolant rose to top of opening.

 

Ok we are making some progress here.
No oil in the coolant or coolant in the oil is good news. Not great news but good news. If you had oil in the coolant or coolant in the oil that would be very bad news.
So since this is happenning at highway speeds that would tend to rule out the fan clutch as just the ram air through the grill should be enough to keep things cool.
With the guage action you are describing and the fact that the other lights are coming on (assuming all at the same time) I would be looking at a possible electrical fault in the dash cluster. Mind you I have been a Chevy guy for the last thirty years or so, so I am not up to speed on the idiosyncracies of Ford wiring (yet).
Also on the GM 6.5 you have to bleed the cooling system when you top it off. That could be a complete non issue here though. I have never seen much less touched a wrench to a Ford V-10 so I can just speak in generalities.

Another question. Does this happen every time you drive it or is it intermittent?

ETA: After re-reading your first post I am curious, when you say you shut it off and then start it back up and it is normal again, how much time are we talking about here? If we are talking less than 20 minutes I would bet dollars to donuts we are talking an electrical issue not the cooling system.

 

It is seconds after it heating up. It is back to normal. Usually just put in neutral turn truck off and restart it and its normal again. It is not everytime. Used to be once a week and now its every couple of days. One day it will be fine for me and the next it will do it 5 times with my husband driving.

Burped the coolant system pretty good when the rad

 

When it is reading hot, pop the hood and feel the upper radiator hose. If the hose is cold the thermostat is not open. If the hose is hot I would be very inclined to look at electrical issues like poor grounds. If it is cooling down instantly I am leaning very much toward an electrical issue. That five hundred pounds of engine and coolant should take more than a few seconds to cool down. Especially when shut down.