As some of you know I've had my Mishimoto Tstat in for a while now, you also should know that after I installed it my temp spread narrowed a few degrees (from 7-9 down to 4-6 Put a couple of hundred miles on yesterday and am happy to say that the temps are holding out well and that at higher speeds and warmer temps they still haven't went to a 9 degree spread yet.
I was on the interstate yesterday ( I don't drive the interstate much) and for 30 miles (rolling hills with few flat stretches) I set the cruise on 80mph, the temps ran 202/210 to 204 to 211/212 But at the 65mph test they were 200/202 to 206/208. These numbers were all with the A/C on ( yes, it was warm enough in Maine yesterday to use the A/C......No,really) My next test will be towing my 9000lbs. T/T the 55mi. to the lake. I dug it out yesterday and will be making that trip soon, I will report back after that happens and I have some additional information to post.

....my water temps have yet to hit the 205 that activates the cooling fan. Which, considering they are 200 plus after warm up should indicate the coolant is flowing well through the system, or so it would seem.

 

Maybe I'm misinterpreting your thoughts ......

This isn't an improvement in how well your oil cooler is working, it's just a change in the value of the number that is referenced for determining how inefficient (clogged) your oil cooler is.

Basically if your Do Not Exceed value before was 15 degrees delta, it is now 12 degrees because you've raised the coolant temp by 3 degrees.

It's like those of us who are running without a stator where the oil and engine block temps have dropped while the coolant temp has stayed relatively constant. We haven't improved our coolers flow rate and efficiently.

The Delta was just a value that Ford found to relate to reduced flow through the cooler with a stock motor. "When we have a X% reduction in coolant flow and the EGR cooler is about to fracture due to its internal temperature we see a coolant to oil Delta of 20 degrees, so let's use a 15 degree value as the threshold."

 

Some folks are reporting better mileage, ie: the engine runs more efficiently at a higher temp. I've always found it curious, unless you change other things like when the fan kicks in, etc.

I see it as: if I start out at the bottom of the hill at 193 ECT and 198 EOT, I have more Headroom for the climb, because by the top I may be at 220 ECT and 230+ EOT (what would it peak out if I start higher?)... Just the way I am wired on this subject...

Lots of folks in both camps, just read the bazillion page Mishimoto thread

 

Does anyone actually know when the fan is supposed to kick in?
Mcrafty says 205, I though it was higher than that?

 

To be perfectly honest you may be right, it's been so long since mine actually kicked in that thinking back it may come on at 210* and back off at 205* I'm thinking that's how it works.

 

I guess I don't follow...but I'm thick headed and it happens to me a lot. However I don't see how the 15 degree delta would change to 12 just because I increased my operating temp a little. I'm not going to argue with you about what I don't understand. I'm just going to spend some time pondering Wait, I might be having a brain fart..let me say this, I was under the impression that the EGR cooler was prone to cracking when the water stopped circulation because of an obstructed oil cooler , not so much as when a certain heat was attained as long as they were still being water cooled and even though I have increased the heat a bit with the higher Tstat it would appear as though I still have a reasonable good flow of water through the oil cooler therefore the EGR cooler also. Are you saying that EGR coolers are cracking when the water get to a certain temp? Sorry if this appears to be a lot of I really do know what I'm trying to say.....no, really

Oh, and I wasn't saying my oil cooler had improved...as a matter of fact I can't explain why raising the water temp could possibly narrow the temp spread. I just know that it has.

 

It happens..... with me oem tstat splits are 5 to 8 and with the mishi they are 3 to 6 with 4 being the norm (ect 204 eot 208)

 

Seems like my standard clutch locks in starting around 208-212*f. My old plow clutch would start locking in as low as 202-204*f, but it would also randomly lock in certain situations like idling in traffic, as soon as I'd blip the pedal it would jump from 0% to 100% and howl, so I don't understand the plow clutch programming logic. The point was to increase air flow when there's not enough (ie blocked by plow or idling when it's 100* outside), which it did admirably well at.

 

Here is the link and part of the post from Bismic's write up in the Tech Folder on the fan operation:

https://www.ford-trucks.com/forums/9...-pressure.html

"Some say fan kicks on at 210, some say 215, others say 220. Full explanation: 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. 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 begins to defuel at 221 deg. The thermostat begins to open at about 190*F to 195*F and is not fully open until about 215*F to 219*F.."