I'll keep this as short and sweet as possible...

Early 2003 F250 6.0L

My step-dad had a leaking heater core and drove quite a ways a way, filling the overflow tank as he went. Once at his destination, he was having issues overheating. He couldn't drive more than about 5 miles without having to pull over and let it cool off. The coolant would boil in that short amount of time. My initial thought was that he had an air pocket in the system since his heater core was dripping out his coolant.

Still out of town, he took it to a Ford dealer to have it diagnosed. They claim he has a bad fan clutch.

He left the dealer and had it towed to a family member's house closer to home. Once at the family member's house, they said they were having a more difficult time getting it to over heat. It would idle for a while with no issue and drive down the road without much problem. After 15 miles, he did have to pull over though, so it's still overheating. He said that if it's under a load, it seems to do better than cruising with minimal load.

Now here's where I'm at. The truck is about 3.5 hours away from me. I'm going to load up the Expedition and drive down to patch the thing back together so he can drive it back home.

Here's kind of what I'm thinking:

1. Replace the heater core. We know it's bad and it's not too difficult to get to. Why not start with the known coolant leak?
2. We're curious if the water pump is on the way out. I'm going to take one down with me in case the old has a broken blade or something.
3. I'm also going to take a fan clutch with me. If it seems to be slipping, I'll already have the water pump off anyway so why not slap on a new clutch.
4. Burp the system.

I'll check the pump and the clutch before I replace them but since I'm kind of time crunched and will be out of town, if slightly shotgunning parts at the darn thing gets it home, so be it.

Any thoughts? Special tools I should take on the journey? I still have a couple days to plan this mission.

Thanks!

 

scanner would be nice to check the fan clutch

 

Get a way to check the coolant and oil temp (live data). an elm327 dongle and a smartphone will do it for less than $40

Richard

 

Go to and oriellys or autozone and rent the wrench for the fan clutch nut. And watch dieseltechron's YouTube video on removing the fan shroud and stator so it puts you ahead of the game. You will also want a large flat blade screwdriver or pry bar that will fit into the slot on the water pump pulley to prevent it from turning while you are breaking the fan clutch nut free.

 

Update -

My family is mechanically inclined and did a large amount of work allowing me to stay home instead of taking the rescue mission trip.

They changed the thermostat, water pump, radiator cap, and burped the system. They still had an overheating issue and towed it home. Thank goodness they had AAA. I'm picking the thing up this morning and will hook up my data logger on the short drive to my house.

First step, I'm going to replace the heater core that is confirmed leaking and burp the system again. Following that, I'm thinking about pulling the radiator and/or clutch fan. This depends on what I find via the data logger.

Other things to note - my step-dad put stop leak in it and is also using Ford coolant, the same type they used in 03. My family members that worked on it told me the coolant was clean and looked good. I'm tempted to run some damn hose water through the block to make sure there is no blockage when I do the heater core here in a couple hours then refill the system with distilled water and Zerex or something of that flavor.

I appreciate the advice given and will gladly accept any more thoughts on this! I'll keep the thread here updated and will post a final resolve when we come up with one. We are starting to get a bit frustrated, curious, etc. I NEED to find this problem. Haha.

Chris

 

Oh also, I'm using a Bluetooth OBDII dongle and Torque Pro on my android phone. I'll try to take screen shots just for fun and future readers.

 

Coolant puking out of the degas bottle doesn't necessarily mean that it is overheating.

As Richard (DarkStarMedia) suggested, please post actual temperature data.

ECT, EOT, TFT, IAT - at KOEO (cold engine), then after it heats up.

Are the two "deaeration hoses" hooked up to the degas bottle (small vent hoses) and not plugged up (EGR cooler and radiator)?

Also, I am not a big fan of stop-leak in an engine.

 

His "idiot gauge" pegs after 15 minutes of driving. They used an infrared thermometer to check the block temp and verified it was hot. I think they read 230°F...

That's my plan when I picked it up in an hour. I told them not to start it up so I can get baseline cold readings and watch the numbers as it heats up. I'll make sure to get all of the above temperatures.

I'll be sure to check. I *think* they are hooked up but I'll pull them off and blow some air through them.

Agreed. I asked him not to put it in but it was a last ditch effort since he was 5 hours away from home.

Thanks for the response. I'll post back later on with more information. I'm just glad to get my hands on it. Working on it over the phone is a pain.

 

Good info on the IR temp scan, thanks.

Does the truck have an EGR delete on it? If so, is an EGR valve still plugged in? Sometimes an EGR delete without a tune or a valve that is "electrically connected" will interfere with operation of the fan (and cause over heating).

Also, make sure that there is no air flow obstruction in the A/C condenser fins or radiator fins.

 

Mixing G05 with any other coolant will tend to make little gel pockets. Adding stop leak to it God only knows what's taking place.

The heater is a bypass unit, in place as a cabin comfort. You can shut that circuit off without any cooling alterations. Ford on some trucks had a shutoff and I've installed my own manual one on my '03.

For the truck to go overheat in 15 minutes I'm not expecting the cooling fan to be the cause. My first thought is there is minimal flow through the oil cooler and the EGR cooler is boiling coolant causing the overheat. But that's just a just wake up SWAG.

 

Once foreign coolant and stop leak is added I would say that your "swag" is a dam good guess. Too my limited knowledge, stop leak in a 6.0 guarantees an oil cooler failure and the associated damage that goes with it.

 

I'm back with more. I changed the heater core. It was bad and needed changed. I also replaced the lower radiator hose, which had 212k on it. The lower hose had gunk in it so I ran some water through and rinsed out what I could. It still overheats. Let's look at what we know:

New:

Heater Core
Thermostat
Water Pump
Cap
Lower Radiator Hose

"Kind of" New:

Oil Cooler
Upper Radiator Hose


Codes I pulled on my first test drive:

P0272 - Cylinder 4 Contribution/Balance - We thought he had a bad injector.
P0402 - EGR Excessive Flow Detected
P0480 - Cooling Fan Relay 1 Control Circuit
P0528 - Fan Speed Sensor Circuit No Signal
P132B

After clearing the codes, verifying an overheat via test drive, changing the heater core and lower hose, burping the system, then testing to verify an overheat again, I had these codes:

P0272
P1000


Here's what's weird about this overheat. I can let it idle for 30 min to an hour and it won't overheat. After driving for a while, it will start climbing into the hot zone. I can hear the fan kick on and as soon as it does, the temperature starts climbing drastically. I found that if I keep the RPM low, even while driving, the temperature will stop rising. As soon as I throttle up and the fan start spinning quicker, the temperature starts rising. If I park it hot and let it idle, it will start to come down again, slowly.

EOT and Coolant rise evenly. Trans temp does not get *hot*. The fan RPM changes with the engine RPM, usually running higher than the engine.

The following are screen shots from yesterday's test drive. I started taking them as the coolant temp started rising. The last is sitting in the driveway idling.

 

x2, I had a heater leak in the mini and put in some Bar's leaks to seal it , worked for a while too. When I got the heater core got replaced they found most of what was inside the expansion tank was a single lump of crud. Even as a get-you-home you have to think about the possibility of the oil cooler getting 100% blocked, or even the radiator...

 

"Here's what's weird about this overheat. I can let it idle for 30 min to an hour and it won't overheat. After driving for a while, it will start climbing into the hot zone. I can hear the fan kick on and as soon as it does, the temperature starts climbing drastically. I found that if I keep the RPM low, even while driving, the temperature will stop rising. As soon as I throttle up and the fan start spinning quicker, the temperature starts rising. If I park it hot and let it idle, it will start to come down again, slowly."

Not so weird, the temp goes with the amount of energy being produced. The diesel is touted as being 45-50% efficient, so half is heat being dissipated by the cooling system, add more energy, more thermal energy has to be dissipated, by the radiator.

You might want to have the radiator checked for flow if the stop leak has stopped flow within it. Your temps for oil and coolant are moving together, so the oil cooler may be fine. Any chance to cut open the heater core?

 

I have the old heater core at home.

More info - I talked to him a bit ago and he said when he had the oil cooler replaced, the mechanic told him he may need to do his radiator as well. He intends to buy a new radiator soon.

I would like to flush the system but I'm entirely too nervous about knocking something loose and clogging the oil cooler. Here are my thoughts. Keep in mind, he's still driving this thing short distances since it takes a while to get hot:

We need to get the stop-leak mess out of there. I was going to run hose water through it then switch it over to distilled but I'm leery of making a bigger mess. I think I want to have him drain the radiator then refill with distilled water. After he runs his short errands for the day, have him repeat the same process. Over the span of a week, this should *gently* empty the system of the crap that's in it now. Once we're fresh on distilled water, we can then switch out the likely bad radiator and see where that gets us.

Thoughts on this? Guide me, sirs!