6.0 Power stroke running hot when pulling
 

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?

the problem with running without a thermostat is that after a few cycles through the system, you're not disipating as much heat through the radiator. If you're going through the effort to remove it, replace it. At a minimum, you know that there is a new one in there.

I'd find a new tech. That is the exact opposite of how diesels work. Gas cars yes, diesels NO. A diesel can run as lean as 500:1 at idle. Their RPMS are controlled by fuel. Fuel is what makes them hot. Air is what makes them cool down. Think about an intercooler. It makes the air more dense, thus adding MORE air to the engine, thus lowering EGT's. The only piston failures you usually see in a diesel (despite the cracking of duramax pistons for some reason....) is from them melting from the heat, from too much fuel!


Thermostats serve more function than what meets the eye. The thermostat will open to allow more coolant which in turn cools the motor better, however, the thermostat is also there to restrict flow. If you took it out, the flow of the coolant would be too high and would go through the radiator so fast it would never soak into the aluminum of the radiator. It needs to be controlled so it has time to dissipate heat. Without you will overheat even faster.

I've never held a 6.0 thermostat in my hand, but I've tested numerous other kinds of thermostats in my life. Take it out of the truck and put it in boiling water and see if it opens. If it doesn't open then it's bad. Again I've never tested a 6.0 one, so I'm not sure if they're a simple mechanical design like I'm used to or if they're possibly electronically controlled?

OK Thanks for the advise and education. I will ask the same question to him and make sure that is what he told me. Like i said before i have more knowledge about gas than Diesel. I have checked thermostats the same way and that had accrued to me. Haven't had time to get it out today not sure about tomorrow but by Sat night for sure. I have to get the gas engine thoughts out of my head. I will not run it without one. I am really afraid i will damage this engine if i can't get this stopped then i will be in court trying to get the guy that rebuilt it to fix it or pay to have it fixed. Will post after i check it.

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Took thermostat out and checked it via boiling water. It was working properly ! Just noticed a small coolant leak , looks like from under the water pump. Not bad but a leak is never a good thing. Leaves about a 14 inch circle on concrete over night. I have been parking it over a big piece of carpet in front of the garage so i had not noticed it before. Getting about 5 drops a minute. It gives me hope that the water pump is defective. I guess Dale Jarrett Ford will find out for sure.

hight temo and water leak
 

A leak is not good however, it could be a small problem or a big problem. It could mean that your cooling system has been exposed to high pressure. This would happen in the begining stages of a weak and failing head gasket. Fix your leak first, then hook up a pressure gauge to your system by tapping into the overfill bottle. Do whatever it is you need to do to get the temp up and watch the gauge, if your psi starts to shoot up its cause you're getting pressure from a cylinder somewhere. Also, without doing any of these things watch your exhaust as you put a load on it, white smoke indicates burning coolant. I know what its like to not have money to throw at these things, oh how I know that. So this is personally what I would do.. Fix your leak, before you put water and antifreeze in, flush your system. Go to powerstrokehelp.com for what it exactly intels. Also I know there are a lot of videos on that page but WATCH THEM ALL. You can get a very good understanding of whats going on with your motor now and how to keep this from ever happening again. Goodluck

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You have an egr delete and a rebuilt motor, honestly this sounds like a small problem. If you do it yourself it's cheap. It could be as easy as fixing the leak, if not then you might need a new oil/ coolant exchanger. It's a pain to get to but you don't need to be a deisel tech to do it. It's in the motor valley underneath your intake manifold. exhaust, intake, turbo and manifold comes off for this. Just be sure to look up the torque values and get new gaskets if you decide to do it yourself.

rsolid
 

thanks guys. The shop had put a aftermarket water pump on it. Looking at it beside the Ford water pump you could hardly tell a difference but there was one. Always remember my lesson here. I went through three months of pulling over and letting it cool (and for a 6.0 that takes a while) i ran cool water through it , i flushed it , i crawled up hills to keep the heat down and a ford water pump completely fixed the problem. These things run right on the knifes edge and it don't take much to push one over the edge. I can get very aggressive with it pulling a hill in 95 = degree weather and it fan hardly comes on now. It almost stayed on before!!! Glad this is over with.

Just to add some random info... I recently had a pretty major leak spring up right there where the water pump is. I believe it to be the spring clamp on the big hose going into the front cover coming from the radiator. I crimped it with pliers to remove it and it never sprung back, so it was weak. I put a hose clamp on instead and the leak went away... just food for thought.