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Discussion Starter #1
Good day guys,

First off, if this is in the wrong place, please direct me to where to repost (or if a mod can move it, that would be great).

My truck (06' 6.0 FX4 with a new to me motor) runs great, but the delta's look off to me. I've had a lot of issued due to the shop that performed the motor swap, and I've worked through most of them with a couple of different mechanics, but it's been difficult as I haven't found a shop that specializes in 6.0s and inherently knows what is and what isn't a problem.

On my deltas, I've read a lot of differing opinions I'm not sure what the issue might be. Initially I thought it could be due to the oil cooler, and that a coolant flush / backflush might be in order. That said, looking at the temps and seeing that my coolant temp stays right at 188.6 most of the time, with a high of 190.4, I'm starting to think it might be the thermostat.

I've pasted a couple of screenshots from my last trip at a couple of different points. The first two were about an hour in and just a few minutes apart. The temp drops quickly from the 190 to the 188, if that matters. The last screenshot is from when I came to a stop just before I turned the truck off.

Any input would be greatly appreciated.

Thanks in advance!


774226


774227


774228
 

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You have some unknown variables that need to be verified first
the coolant temp sensor should read ambient after the truck has sat at least over night, along with the oil temp and transmission sensors

The T-stat sets the lower limit for coolant temp, and the fan sets the upper limit
Does your truck have the original fan or has it been modded?
T-stat should be 192-197, but need to know if the sensor is reading right first

You can hang the T-stat in a pan of water and use a candy thermometer to read the opening temp
IR thermometers do not work well with the steam -- but a digital probe may
 

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Discussion Starter #3
You have some unknown variables that need to be verified first
the coolant temp sensor should read ambient after the truck has sat at least over night, along with the oil temp and transmission sensors
I need to check the transmission sensor, but I can confirm that the EOT and Coolant sensors read close to the ambient temperature at key on after sitting for a long period of time.

The T-stat sets the lower limit for coolant temp, and the fan sets the upper limit
Does your truck have the original fan or has it been modded?
T-stat should be 192-197, but need to know if the sensor is reading right first
The fan is original as far as I know. I bought the truck used, and it did have some modifications, but there was no mention of an upgraded fan when I bought it. I guess my next question with this is, if I raise the coolant temps, would it then raise the oil temps as well? My deltas on the last motor were between 8 and 10 degrees, and if the oil temps don't go up, I think I'd be close to that again.

You can hang the T-stat in a pan of water and use a candy thermometer to read the opening temp
IR thermometers do not work well with the steam -- but a digital probe may
I'll throw it on to check it when I have it out. I'll replace it regardless as it's not too cost prohibitive.

Thanks again!
 

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IMO a thermostat that normally runs in the 189 - 202 range is not worth worrying about. Personally, I would prefer it.
 

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I would "boil" the new T-stat so you know the opening temp going in the game. There has been a lot of variance in what others have reported -- just hard to get quality parts anymore.

I agree with @bismic , that temp is not much worry, but it will throw off the delta measurement -- which is a much abused term in this engine world. Consider engines that do not use an oil cooler and generate a lot more heat than a diesel (gassers) -- The oil cooler is not the only place this engine "loses" heat, plus being a diesel, it is "air cooled" to an extent via the intake air flow

Look for the fan wiring harness at the radiator shroud -- that should tell if the original fan clutch is present or not.
 
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The other situation is you are trying to fingerprint this at a higher speed. There is a speed deviation to the differential, more so depending on the cooler's flow, more open coolers show this less.

The common way to get consistency is to be running at a steady state of between 60-65mph, on the flattest ground possible at a lightweight loading. This will give you a better differential reading between the coolant to oil. It would help if you had a dwell time at speed and not look at it when about to shut down, too; the two fluids will have settling rates.

I also have no issues with 188 to 192ºF, but a cooler running T/S can lead to a few degrees high of the differential between coolant and oil.
 
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Discussion Starter #7
So, if I'm reading this correctly, I'm doing my test incorrectly ;)

I should be running a steady rate of 60-65 on a relatively flat stretch of road at "normal" operating temperature. I don't quite understand the "dwell" time, but can I assume that's the amount of time I'm running 60-65 and monitoring the temperatures?

Also, it seems like there's not much to worry about at the 188.6 temp, which makes me happy. I had read that if it was less that 190 (and should be closer to the 195) there was a problem, but what I've read is all over the place, which is why I posted this.

I guess I should add that I have a couple of longer trips coming up (a few thousand miles), and I don't want to run into any issues on the road, so I'm just trying to get some warm fuzzy feelings that my truck is running as it should.

Thanks again!
 

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My dwell time comment is that you can see the coolant change in temp quicker than the oil temp; people can get all randy if all of a sudden they see a high differential.
 
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It's like when you are driving and see a good looking Woman Truck, - dwell time is how long you continue to look until you realize your out of your lane
 

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FWIW - I never have seen oil temps more than 10 degrees above the coolant temp - driving speed, towing, accelerating ....none of that caused me to exceed the 15 degree differential. I acknowledge that my towing has never been above 8k-10k.
 

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Discussion Starter #11
That makes more sense :)

I should have my wife drive while I watch it...I can say that the thermostat gets to 188 and stops while the oil continues to climb until it gets to around the 202 mark, and then it slows and is a bit up and down, That doesn't really coincide with what the coolant does, although the coolant will jump from the 188 temp to the 190 temp and back down. I can't say I've seen over the 206, but then again I can't say I haven't either.

Overall would you say I'm overreacting, or is what should my next step be? I do have a shop I'll be contacting later this week that should have some expertise, but I was getting ready to push a diesel shop with less experience to backflush the HPOP because that was one of the recommendations I read when I was looking at deltas. This is why my wife should keep me off the internet :D
 

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You aren't going to see stable temperatures on an exact number. The fluids vary around by several degrees, and the sensors are not exactly precise.

The oil temperature always will lag the coolant temperature for a good bit of time when starting from a cold engine. Takes a good 10+ minutes for my oil temp to catch the coolant temp, then it exceeds it and stabilizes.
 

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But you have always had a good, clean, well flowing cooler Mark. As mine got compromised, I saw more of a differential with the load variation, speed or 12k tow.
 
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Discussion Starter #14
This was unloaded, on the highway. I don't have a load to test it with at the moment, but it doesn't sound like it's necessary.

As mentioned, my previous engine never exceeded 10 degrees that I saw, which is what spurred my concern to begin with. When I first got the truck I read about the issues with the HPOP and oil cooler, and I did my best to try and monitor what was going on. It didn't help with the HPOP (which is what caused the catastrophic failure of the old motor), but it seems important.

I'm continuing to see a recurring theme here..."a well flowing cooler". In your experience, should I entertain a coolant flush (Ford procedure or other), and even a backflush? I've seen may different processes (there are tons of threads on here). Some say it's a savior and others say it's just a patch and that an oil cooler failure is inevitable.

Maybe I'm misunderstanding what I'm reading. It's a common occurrence.
 

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Putting a lot of faith in that temp sensor, need to verify that all 5 read the same
 

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We are now getting into opinion areas. For me, it depends on what is clogging a cooler. Going all the way back to Nylyon's first presentation of a cooler issue and quickly developing a second situation with a brand new cooler, it depends on what is causing a restricted flow.

If it's a coating on the inner paths, it requires a new cooler, IMO. That is something hard to clean. I did extensive chemical work on my entire system, and it never fully cleared. A decade later, replacing my heater core and cutting it open still had the coating.

Cutting open two coolers and looking at the intake ports, there is a potential for large particles to block the intake ports. Those have not adhered to the ports chemically, and they are a mechanical attachment.

Many have been able to blow those out, although it is a difficult procedure due to the gooseneck direction of the coolant flow's intake path. It's best to pull the water pump when doing this. And it may take several tries to clear.

A cooler hampered with silicate that I cut apart.


IMG_4051.jpg IMG_4221.jpg


A cooler blocked in the intake ports, no silicate.

IMG_4237.jpg IMG_4025.jpg


My heater core.

IMG_8474.jpg Screen Shot 2019-10-27 at 7.40.38 AM.png

I haven't cut open my radiator as yet.
 

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I would run your test again like TooManyToys stated and see what you get for readings.

I had good success by doing a backflush.
 

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I haven't cut open my radiator as yet.
I can see the thread now... "HELP! Large coolant leak after cutting radiator open" LOL

-jokester
 
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Nothing that a little JB Weld can't handle.

I have its replacement.
 
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