Update... 110 degrees here today and I drove for a while on surface streets with quite a few stops at lights. The temps stayed right around 200 to 205 like they do every year when it gets hot here. I'll keep monitoring the temps.

 

Good to hear. I am getting ready to swap to ELC on Monday and noticed a crack on my degas as well. Slow leak, the coolant dried up around the crack, looks like a white scab the size of a thumb on the lower right side where if taken off the mount it would rub up against the hydroboost lines. Not leaking bad like what you described, but I don't want to take any chances, gonna swap mine out as well. Thus far, no spikes in temps. My scanguage temps read about the same as yours, I get about a 9 degree spread on the highway.

Thanks for posting and getting great replies from the experts!

 

I purchased a new bottle at Ford Country for $87. I looked closer at the broken bottle and it had several other cracks that had not yet gone all the way through. Its this damn heat here!! lol. Just replaced tires too... other tires were 3 years old and started cracking bad and tread falling off in places.

 

The fan clutch has been replaced and now it seems worse. One thing I noticed was driving around the volt gauge was jumping from about 11.8v to 13v... it kept going back and forth. While driving around the EOT and ECT got up to 220 degrees... the fan never came on. When I got home and parked the truck I turned the high idle on and the engine was surging. No check engine light or wrench light either. I checked all the electrical connectors in the area and all seem fine. I really hope the new fan clutch isn't crap, that was a royal pain getting it off and back on again...lol. Any suggestions?

 

Jonathan - do you have any way to monitor fan speed? The scangauge will do it.

 

unplug the icp and see if the surging goes away. it wont fix your overheating issues though

 

Thanks guys for the replies! Well today I received the ODBII Bluetooth adapter for a Droid phone. This morning before I drove the truck, I checked all the electrical connectors around where we were working on it last night (unplugged them and plugged them back in). I took it for a drive and noticed the volt meter was normal with no erratic fluctuations like last night and with the high idle switch on, the truck wasn't surging (this is good). I took it for a drive this morning before I got the Torque App configured and after about 30 minutes the temps again rose driving in town, so I took it on the freeway and the temps went back to normal. After I configured a few parameters on the Torque app including FAN SPEED I went out again for a drive. First off the fan speed was around 375 rpm's while driving down the road. I kept on surface streets to make it heat up. I'm only monitoring ECT right now.. EOT wasn't working right. ECT, after a while of driving, got to 219, the fan RPM's shot up to 800 then 1100 then the ECT went down to 206 and the fans RPM's went back down to around 350 ish. This went on several times.. I'm thinking great it's working, then all of a sudden the ECT went up to 221 with a fan speed of 289 rpm's, ECT rose to 230 and fan speed stayed in the 200's. So I drove it home and parked it. So it seems to work just fine for a while then it stops responding. Weird! The Fan rpm's even went as low as 189 rpm's with an ECT of 231.5. I wondering if it may be a bad wire or connection.

 

Thats what it sounds like

Any DTC????

I hit 218*ECT and Fan speed is 1100-1500rpm or so

At 221* ECT the engine will Defuel

 

just curious.... how does the computer regulate the fan, and how
does it supervise or get feedback on the speed of the fan?

my rebuilder said "you need the h/d snowplow fan" when i rebuilt,
and as i was throwing a 0480 code, i agreed with him.

what i'm leading up to, is does the pcm get an actual feedback, or
is the speed inferred by what the pcm does, without any real verification
that the fan is doing anything other than being plugged in?

 

I scanned with the Torque App and a Craftsman code reader and both show no codes. What is strange is that the Isspro gauge for ECT was showing 205 and the Torque gauge was showing 221. I was also wondering if the thermostat is sticking.. I just replaced it 1 1/2 years ago. I am about to pull the thermostat for a few days and see if that helps. Also, when the ECT (on the Torque app) hit over 230 the dummy gauge on the dash moved up a little from the usual 1/2 way mark to about 2/3. What is the highest rpm the fan will go?

 

Another thought, when the fan jumped up to around 1100rpm I could not hear the fan, you know the big roar that it makes... I heard nothing. I had both front windows rolled down.

 

I wonder what other variables are involved other than ECT, EOT and TFT that determine when the fan should kick on. Is it possible the PCM is going south? The truck runs great other than the fan clutch not being regulated properly. Thanks everyone for your replies.

 

Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some 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), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements (NO EOT input). 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

Engine oil temp is apparently not involved in the logic.

 

Either a BAD ECT temp sender the OEM one or torque app gauge is wrong


Im leaning toward a BAD OEM ECT temp sender


what do ECT & EOT & TFT read after 12hour cold soak are they the SAME??? with torque app???

Somethings up You MUST verify the condition of the OEM Coolant temp sender as thats what giving info to PCM for Fan Operation

The Issopro gauge is OK but what the PCM is seeing is Key to figuring this out

 

thanks for that... and thinking about the design of the engine,
it's not surprising there is no EOT in the equation. the EOT and
the ECT should be very close if not the same, so why code for it?

what i'm not getting, is why they didn't put a line of code in the pcm
to set a code and turn on the check engine light when the delta goes
over say, 25 degrees between our two favorite temperatures....

it would save a lot... of grief. but it would also weaken fords position
in defending against a class action lawsuit, as it would be an admission
that there is a problem with that engine assembly, as the code didn't
come out with the engine when new. if you added it later, it'd be an
admission of a problem.

after the pinto gas tanks, ford probably is a bit gun shy of anything
documenting knowledge of a problem.