Just had my 2004 6.0 King Ranch rebuilt after the oil cooler ruined the engine. Thought we had the over heating problem fixed until today. It has been 100 + degrees out but starting off pulling a load and hit a hill and need to ask a little more from the engine and there it goes. The fan comes on and if it is a long hill 1/2 mile or so , up goes the temp. If i can get the hill made and ease off the peddle she will cool down a little but the fan runs all the time when pulling.
It has been one expensive thing after another and i have been dealing with crap like this for over a year. Can someone please tell me why i can't get it to stop running hot ? Went through this one time and changing the water pump stopped it , i thought for good but now it has started back again. I am desperate for answers to this problem
rsolid Monroe NC

 

You need to do some data logging and verify that the oil temps are actually getting hot and not just a bad or over active fan clutch.

Sounds to me like that is your issue. A bad fan clutch.

 

Could be as simple as the sensor as well. I agree, datalog it. You need to check engine oil temps vs engine coolant temps.

 

The coolant temp jumps up and down pretty fast. Once i ease out of it , it cols as fast as it heats. The oil temp. is and has always been normal. Once it warms up it stays the same.
The clutch can't be bad because it reacts and then the gauge confirms it was heating. I don't understand for the life of me how it can run fine for two months and then start this up again. It acts like a head gasket but it has only 3000 k on the new engine. I have 0 confidence in the truck right now and if times were better i would trade it in. I do concrete work - need i say more?

 

Believe me, I totally understand where you're coming from, it can be very frustrating. We can at least help you get it narrowed down.

I'm guessing here.... that you're going off the factory gauges? Well they are all but useless as you can probably already tell. The gauge is more like an on/off button. It goes up to the middle of the reading when running normal, and only goes to "max" when it gets too hot, there is no in between there. We need real numbers which can only be had by datalogging. See if someone in your area can do it for you, anyone with an SCT should be able to log it for you no issues. You can probably bring it to Ford and have this done, but of course you're going to have to pay for their time, and I'm sure they'll try and sell you some stuff.

How is your coolant level right now? It could still very easily be a sensor failing. Electrical components do funny things when they get HOT. If the sensor is bad and giving false readings it would most certainly kick the fan on and off. I've had my fan kick on a whole bunch even when I was really low on coolant and barely working it in 50 degree weather, BUT never had the coolant gauge max out like that. Oil gauge once, but that was my fault. This is why I'm thinking it could just be a sensor.

I forget did you have an EGR delete or not? I think you did right?

 

Yea i did the EGR delete. Going to my mechanic (final payment). I will most likely go to the Dealer (Dale Jarrett Ford) remember them? If they had diagnosed it right last year i would be 7 K better off. Sad when you don't know where to turn for a professional in this field. The way you talk about the gauges makes a lot of since. It turns on and tells you your screwing up and then back off. Mdub707 you have been so much help. I can take a pre 1985 Chevy apart and rebuild it with no trouble but when it comes to this new computerized diesel i am lost. I will talk with my man tomorrow and set up something with the dealer. When the dealer data logs it , do they do it on a dino or will i need to have something to pull? May sound like a stupid question but want to be perpaired. Thanks

 

The tech will come out and do a ride-a-long with you, he will just hook up to your truck and log as you drive. I would specifically request that a tech rides WITH you, not just drives your truck, so you can duplicate the issue. Whatever you need to do to duplicate it... though you may not need that trailer, your temps might just be up even without, but not enough to really overheat it. Regardless the tech should have no issue checking EOT vs. ECT.

The next gauges I'm putting in my own truck are going to be Fuel pressure, EOT, and ECT. I should have got those from the beginning (along with my pyro).

I hope for your sake it's just a simple sensor, that's what I would point at personally, but it's always hard to diagnose over the net. Let us know how you make out.

 

Latest update. Went to Dale Jarrett Ford today and had a datalog done. Only thing out of normal is fuel pressure is 10 lbs low. Not enough to cause it to over heat ? They didn't think so. Want me to bring it back 1st of week to check thermostat , water pump for defects. Nice enough to not charge for today. I go to church with the shop foreman and he said he would cut me a brake on the hour rate. Will this ever end ? I am starting to wonder !!! Thought sure it was a bad sensor because it is never the same from one day to the next and some days you would think nothing was wrong. I guess if i throw enough money at it , it will heal itself ? Any ideas are welcome.

 

Fuel is what causes heat in a diesel, more fuel, more heat, less air will equal more heat as well, but its usually a more instantaneous heat. Definitely sounds like a coolant restriction (if it's not the sensor).

That was nice of them to not charge you for the ride-a-long. They probably did that expecting you'd come back haha.

Low fuel pressure is a killer on the injectors for this motor. You're not running a programmer though right? 10psi low could just be a worn out spring in the fuel bowl that acts as the regulator. A weak fuel pump would be worse I would think. If you're out of warranty and they want to replace the pump, just get an Airdog II, it will keep a constant supply of fuel to your injectors and filter better too. It's also cheaper than stock.

Thermostat could be a simple fix yourself I would think... I've honestly never even looked into it, and I doubt they're very expensive, might be worth trying to fix yourself first...

 

The way the man explained it to me was rather like a nascar engine. If they are leaned out to much they build more heat and burn a piston. It's like a lean diesel will run hotter than a rich one ? What if i were to remove the thermostat to see if it runs cooler? The luck i have had if i buy a new one it will be bad too. At least without one i would know for sure. Would that cause a problem? I know it wouldn't on a gas engine but not sure about a diesel.

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I know i couldn't run it that way , just do this for a test?