On my F450, I finally got my thermostat in the mail, put it on, and now difference. Thought I'd fixed it - drove about 20 miles on the highway with temps below 210 and decent deltas, then, as before, the EOT slowly started creeping up, got to 215 without ever hearing the fan kick in. At that point, I started manually activating the fan and headed back home. Again, I ask, does it make sense that the fan acts find with the blue wire ground, but never kicks on by itself? Or does it indicate a bad fan clutch?

If I need to replace fan clutch, since I don't have the special wrenches or air hammer to remove, would it be crazy to give a half mile to the shop and have them remove, then drive home without it or the belt on, or do I need to pay the shop to do the whole job? That sounds stupid, I know. Just tell me so, I'll believe you.

Someone else suggested water pump, which still means I have to take the fan off. If I need to replace the fan, I'd go ahead and replace the pump while I'm there since it doesn't cost that much. But, if replacing the pump could fix it, I'd rather not buy the $300 or whatever fan clutch. Like I say, it just seems odd TO ME that the fan works fine with the blue wire mod.

NEXT: I've gotten nowhere on the E450 transmission problem. Got my first ODBII adapter in the mail, and it didn't work. They sent me a replacement that works somewhat, but something isn't right. When I access the Faults function in Torque Pro, I get an ECU error message about the vehicle not allowing it to read PIDs and suggesting that maybe the truck hasn't been programmed to allow that. I click past that, and it scans for codes and tells me I have 20 something, a bunch of stuff I've never seen.

I switched it over to the F450 and get the same ECU message. The first time, it said that truck had 20 something faults too. I cleared it and drove a bit, then again the next day and it was down to 3 faults only one being mechanical - something about exhaust pressure. The BAFX tech told me to try the Piston app, which I downloaded and used while driving the thermostat test and it said no faults. I'm thinking the first read was just repeating the results from the E450 test.

So, I tried the Piston app with the E450 and never could even get it to pair up. The phone is paired, but not the app. It says OBDII error. I'm going to go back to Torque Pro on the E450 and write down all those Faults it finds, if it finds them again. Recall that this is a flood truck. Ever hear of an ECU not working with the OBDII, but seemingly working otherwise? Just my luck.

Think I'll also try the F250 just to see what it does. Would love some consistency.

 

I had the 20+ codes i'd never seen when I first hooked the system up. I cleared them and only paid attention to the ones that came back. Torque pro didn't give me everything, however I bought this adapter that hooks to my laptop via USB:


And i downloaded the forscan for windows desktop application and it worked infinitely better. Torque seems to read more basic stuff, but forscan gives me everything. It even detects that my overhead mpg calculator thing isn't working. Forscan did the 20+ codes in every system, so I've resorted to forscan for diagnosis, and torque for just a static display of temperatures and speeds.

 

Thanks, Jay. I may have to get that too then. I think I have a bootleg copy of Forscan on my other pc. If I have Bluetooth on that PC, can I use the adapter I got?

 

PCM looks at ECT to kick fan on, not the EOT............someone correct me if I am wrong.
That explains why it won't kick in, likely the coolant is not warm enough.

 

Coolant temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that we see variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor sensor inputs and control the VDF speed based upon engine coolant temperature (ECT), engine oil temperature (EOT), transmission fluid temperature (TFT), and intake air temperature (IAT) requirements. Also, the air conditioner high side pressure switch will cause the fan high speed to activate (ACP V). When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF.

 

One thing I have noticed is that restricting the small vapor hose return to the degas bottle can cause temperatures to run higher. Specifically the one off of the intake manifold.

 

Great info Mark thanks, I never realized there were that many variables.........I've heard some say this engine was a little ahead of it's time technology wise but that seems a bit over engineered!

 

Thanks guys, wish I understood all that. I'm just puzzled at what is not causing my fan to come on and cool the engine. Thinking about it today, it occurs to me that's the same thing with my son's truck - it gets hot too and I never hear the fan coming on. Neither truck loses coolant or has oil/diesel in the coolant. His truck heats up faster and prolly doesn't pass the 5m/65mph/15delta test. My truck will pass that test, very nicely, but 10-15 more miles and the EOT starts ticking up, a degree every minute. Around town, it never gets hot. Idling it never gets hot, it cools way down. It only gets in the 220s after 10-15 miles at highway speeds.

Maybe those are typical symptoms - heck, I don't know, I'm only learning these trucks one failure at a time and haven't had any cooling problems yet. My first truck, the fan would start screaming at 212 degrees like clockwork. When I pulled a big load up a steep hill once and it got to 224, I freaked out. Now this truck does that just cruising down the highway, but the fan never comes on.

Yet, I can ground the blue wire and the fan kicks right in just fine, and the engine cools down. I haven't done that until it got to 215ish, and was able to get it back under 210 after a couple of long fan bursts, but think if I'd done it sooner, it may never have gotten to 215.

I'm thinking it's not a chafed wire or grounding it wouldn't make it work - I grabbed the blue wire right at the connector, on the engine side. It seems like the PCM is just not telling it to turn on.

But, heck, I don't know. Maybe those are obvious signs of a bad fan. Or a bad water pump. I only know how to tell a bad pump when it leaks water.

Guess I'm just trying not to get hosed in typical Bonehead fashion - by tearing it down to replace the pump, when that doesn't work, tearing it back down to replace the fan, and when that doesn't work, tearing it down to replace the oil cooler. Since it drives so well otherwise, I'm thinking it's just one of those things, or something else entirely.

But, I'm going out right now to check those degas bottle hoses.

Thanks bunches. I have three trips in the coming week - two to Austin and back and one to Dallas and back. As long as I drive 55, it stays under 220, but that just seems like a breakdown waiting to happen.

 

Both small degas hoses are clear. Disconnected both at the bottle and blew in them. The one going to the radiator first, and pressurized air escaped when it pulled it loose. Felt clogged when I blew, so I pulled the other end and it blew clean. With it still disconnected from the bottle, I disconnected the one to the intake. Surprised at how fast coolant came out the open degas port, lol. But assume that means it's clear too. I'll see how it goes tomorrow, with me manually running the fan all the way to Austin and back. Supposed to be 101 there tomorrow.

 

Well, I know I'm a noob, with all my uninformed symptoms, but here's the latest info:

Drove to Austin yesterday morning. Left before daybreak and drove all the way there with no problem. Truck ran 213-215/200 the entire trip, which is basically what it's always run at. Returned that afternoon by which time it was 100 degrees outside. Delta always stayed around 15, but it ran 220/221ish.

Still never heard the fan scream. I manually ran it a few times, but it'd only lower EOT temps for a few seconds.

I guess my major problem is that is just so dang hot. I could prolly cruise around in moderate temps just fine for a while. But, I'm now guessing that my oil cooler or water pump could be replaced as well. Maybe I'll try the cheaper water pump first, although without an air hammer or special tools it'll be a pain. Unless this new info makes y'all think it could be the cooler for sure.

 

 

Whoa, that's good to hear. Everyone here is talking about normal being 200, maybe up to 210. My deltas always run close to 15, but I chalked that up to heavy truck, low gears, pulling a trailer. I just hate to blow this one up - at least not until I get my shuttle bus working, lol Dang, coolant at 230, that sounds crazy. I've had EOT at 227, but my coolant was still in the low teens, and I thought I was gonna blow. Pulled over as fast as I could and let it cool in a parking lot for an hour before turning around and taking the long route around the mountain.

 

 

I've been driving with the same high teens deltas for about 60,000 miles. 99% of the time, the truck is pulling a trailer - not huge, <10k/lbs, but still enough. But the temps weren't getting about 220. However, I've not driven it in this Texas heat - last summer I spent most of the summer way up north in cooler climes. Still, 60k miles is prolly due for a cooler anyway. I have no reason to suspect that its ever been replaced before (215k total miles) since the STC fitting wasn't changed either. Thought I'd tackle it when I got back from my trip later this week, but today I clipped a car with my trailer's fender turning in a tiny cul-de-sac, ^&%%)* and have to buy her a new bumper cover. Don't pull this longer trailer that much and just forgot to check my mirror.

Dang, last time I tried to replace a cooler, I never got the engine to run again. That truck is still sitting in my driveway. Hoped to have my shuttle running so I could still make money in case I screw this one up too, but can't get my scanners to read the fault codes on it. ^*&*&)*&)%$^# Ain't looking good. Not sure how long my luck will hold out.

 

Coolant at 230 is not good in the 6.0L, Not apples to apples when you compare the 6.0L to that of gas engines or non-EGR engines.

The PCM begins to defuel over 221 ECT. That is well documented in the Ford PC/ED manual.

Also, remember that the oil temp isn't the hottest point in these engines. The oil in the pan can reach up to 50 degrees hotter temps, and in specific locations in the head and block it can get even hotter.

There wasn't much safety margin put in from the factory on the cooling system design. As an engine ages, it loses some heat transfer efficiency. Even by design, a fair amount of heat transfer is done by nucleate boiling. On an engine that does not have much safety margin it can even become excessive. This marginal cooling issue has been shown to exist by the benefit that is achieved by installing coolant return lines from the back of the heads.

You can see on the various 6.0L forums quite a few degas bottles are cracking and requiring replacement. Enough that to justify a few companies offering aluminum degas bottles (not cheap either). That is a direct result of operating temperatures being too high, too frequently. Same w/ the cracking "y" in the coolant hose below the degas bottle. Also remember, the higher the coolant temps, the higher the degas bottle pressure.

I am a stickler for the 15 degree differential, but in reality of you are at 17 when towing in some high heat region of the country, you are probably OK w/ the oil cooler.