6.4 Hemi oil temps

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ScubaSteve178

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You could very well be right. But there are a number of stories/videos where temps runaway and lead to overheating past 250 degrees. Not just the hemi, GM has overheated on TFL and the Ford EB too.

Basically if we're pulling less than GCWR up any road in North America in the middle of summer, I still expect my truck to do so without overheating. The fact that it stops around 250 is more a result of "running out of hill" than it is anything else. In other words, the cooling can't keep up and the only reason it gets back under control is because the load goes down.

Maybe I'm expecting too much? But I definitely prefer more cooling.

Well...I mean...overheating is always an indicator of something not working properly, or being worked harder than it's designed to.

When it comes to overheating, regardless of what thermostat you put in the engine, once the target temp of the thermostat is reached, it opens up fully and is no longer any more of a restriction than any other thermostat. Then it becomes a matter of whether the rest of the cooling system is up to the task, ie: the radiator and fans...and I don't know about you, but radiators nowadays are also much better, and usually have a cooling capacity beyond what the intended use would require.

More to your point of being under GCWR, if you haven't seen the temps exceed what is considered normal, I don't know what makes you believe they necessarily would.
 

ramffml

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More to your point of being under GCWR, if you haven't seen the temps exceed what is considered normal, I don't know what makes you believe they necessarily would.

Others have exceeded "normal", I just haven't reached a long enough grade yet.
 

Wild one

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Others have exceeded "normal", I just haven't reached a long enough grade yet.
I know where's a grade you can try out, and maybe see a Grizzly and her cubs in the ditch,lol
 

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Dutra

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Just my lemon. Got the extended warranty thank goodness. After it blows up I’m selling
 

2003F350

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Guess my truck just runs hot?

View attachment 539377
Gonna go ahead and say you've got a LOT of issues if that's a 6.4 Hemi. Was that taken at idle? Because except for ONE time I never saw less than 50 psi for oil pressure when moving, and NEVER saw oil or coolant or trans temps that high, even when pulling.

You likely have a partially blocked radiator, from what I understand casting sand can be an issue on some 6.4's. I'd put a laser heat sensor on the top and bottom of the radiator after it's up to temp and see what that delta is, it should be FAIRLY even.
 

Dutra

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Taken at idle in line to cross the border in mexico when it was about 115 degrees outside. I know for a fact my fan clutch was no good just changed it out last weekend. 30 psi at idle is normal from what I’ve been reading.
 

2003F350

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Taken at idle in line to cross the border in mexico when it was about 115 degrees outside. I know for a fact my fan clutch was no good just changed it out last weekend. 30 psi at idle is normal from what I’ve been reading.
Yeah 30PSI at idle is pretty normal, I think mine settled at about 34. But those temps are pretty high, if your fan clutch was no good it SHOULD have failed in the 'locked' position so it should have been pulling full air all the time, meaning your temps should have been lower. I still think you've got something going on in your cooling system, my GUESS would be a partially blocked radiator but without investigation it's hard to say. You're definitely running a bit warm though, even in those temps.
 

Dutra

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My fan was easily spun with my hand on my Dodge. On my Tacoma the fan hardly moves by hand. My neighbor has a ram 3500 and his fan was a lot harder to spin by hand. Also with my truck running I can stop the fan with my hand. On my Tacoma I tried the same and nearly cut off my hand!!

Only problem with a partial clogged radiator I cannot duplicate those temp results. It doesn’t get that hot where I live.

On the old fan clutch I used torch and heated the center of the coil spring and it moved some. But it took way to long to get back to normal position. I marked the spring in cold to tell what was normal position. Im 99% sure it was the fan clutch
 
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