I've owned my 04 F250 6.0 CCLB 4x4 for a bit over 2 years. I have never had an overheating issue before. Yesterday, I bought a 31' camp trailer (bumper pull). On the way home, the temperature started climbing, and I got the "check gauges" light. I pulled over to find no obvious leaks, no steaming, nothing. I called a friend, let it cool a bit, and got a little more antifreeze and added it. A little backstory is that I had a pinhole leak in the reservoir and had just been refilling it occasionally - so I thought maybe I diluted the anti-"boil" too much and that adding a bit would help. It made it most of the way home at what appeared to be normal temperature, but had kept the A/C off the entire time. When I got about 4 miles from home, I flipped the A/C on, and within 30 seconds the temp needle started to climb. I turned it back off, and it stayed <3/4 range on the gauge the rest of the way home.
Lastly, I had ordered a thermostat and a fin comb for the A/C condensor (it looks about 30% blocked). While pulling off the intake and IC tubing to access the thermostat, I found the electrical connector on the shroud disconnected. Now I'm wondering if that could have caused my problems.
I already purchased the thermostat, so I'll probably replace it anyway. But could this have cause it?? I was pulling at 65ish mph, I would have thought at those speeds the fan would be irrelevant. I don't think I'm losing ANY coolant, so I don't think head gasket.
thoughts? suggestions?

thanks,
Jon

 

The fan is very relevant on these trucks, and if it was unplugged (the clutch) that right there could have been why your truck overheated. Just around town if I've got the 5th wheel on the hitch I'll hear the radiator fan spoil from time to time. The OEM dash gauge is an idiot light and doesn't reflect any real temperature that the engine is experiencing. The CEL light means that the PCM detected the engine had exceeded a preset parameter...in this case ECT -engine coolant temperature. Do you know if your oil cooler is clogged? That can/will cause the truck to over heat...and depending on when your truck was built (before or after 9/23/03) if it is clogged you could be risking a blown EGR cooler. One other thought, changing the thermostat isn't a bad idea...but they're designed to fail in the open position. Thus your overheating issue more than likely wasn't because of the thermostat.

I'd look into fixing your leak in the degas (overflow) bottle, plug the fan clutch in and check to see if your oil cooler is clogged.

 

The degas bottle has been replaced, I plugged the clutch fan in as well. I'm also going to comb out the heat exchangers. How do I go about checking if my oil cooler is clogged?

thanks,
Jon

 

You'll need a diagnostic tool that plugs into the OBD-II and allows you to view the ECT and EOT (engine coolant temp, engine oil temp). Scangauge II and AE both will, I think an Edge CTS will. At which point, you'll need to drive the truck at 65mph (unloaded/no trailer) with the engine up to operating temp. You'll want to compare the ECT & EOT at that point, if the delta (spread) is more than 15F your oil cooler is clogged.

 

Gotcha, I have AE, so I will do that as soon as I get her put back together!

 

That means 15 to 20 miles at highway speeds on level ground. Deltas mean nothing if climbing, cresting or descending grades. The factory gauges are worthless for this test or anything else for that matter. The boost gauge is the only half way reliable gauge from the factory.

 

hmm... any other tests? I don't think I HAVE 15-20 miles of flat roads....

 

In Kansas you don't have that much? Seriously? Slight grades will be ok, what he's talking about are grades like some of the stuff around KC or climbing hills. Little rises will be fine because if your close to 15F a small rise isn't going to be the end of the world. But to test if the oil cooler is clogged...that's the only way I know of, short of tearing the engine down.

 

Not in my parts... hills are graded enough that if I use cruise control on the truck at 65mph my speed will vary from about 62 to 69 or so. The interstate doesn't vary as much, but is either mostly uphill or mostly downhill.

I'll check it out anyway, but I know if I've got hills and its still not over 15 degrees I should be good.

 

Use the interstate...a little more controlled gradients. And watch to see if the engine is spoiling the turbocharger more than a couple of pounds. If it's building 10 psi or more...it's going to mess up the test because your working the engine pretty good. There are some folks on here that have a 10F degree delta with good oil coolers...but most are down around 3-4 degrees with healthy oil coolers. If the delta doesn't get over 15F and your pulling a grade for a couple of miles...yeah I'd say your oil cooler is just fine.

 

Will do!

On another note.... my condenser sure was plugged up with bugs and guts... not to mention the bent over fins... but looks much better now.

 

clean straight fins, fan plugged in, I bet it will all be good now. my torque app shows my fan at 500 rpm pretty much right from start up.

 

I'll probably do the oil cooler test Tuesday morning, and then hook up to the camper again and pull for a while to see if she's all better. I have plans to camp Tues and Wed night... although my total distance is only like 7 miles.

thanks for all the replies and insights guys,
Jon

 

From what Zhilton and others who are ford mechanics have said in the past it can be assumed that a greater than 15 degree delta is normal and OK when working it hard.