6.4 Hemi oil temps

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amjones182

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For those running a 6.4 Hemi in a 2500 what are your average oil temperatures? In my truck was new I remember it running around 212. With 33,000 miles it is not uncommon for it to get up to 222 on a nice 80 degree day and up to 228 when towing my 6000 pound travel trailer. I have been unable to find the spec on what the Optimum range should be.

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amjones182

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Coolant temp is around 210-212, trans is 168 and 53psi during normal driving.

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Andrew09HEMI

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I'll have to look next time I'm driving and up to temp but keep in mind oil does a lot of your cooling so it'll be close to your coolant temps if not a tad higher. Again, I don't know what the norm is as I haven't checked mine but I will when I drive it today
 

Swampfox

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I have seen it around 235 pulling trailer on long grades in the mountains. Cools back to 220s quickly after uphill climb. Normally 215 to 220 everyday driving
 

RAM_Designs

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210-215* for oil
165-175* for tranny
Oil pressure in low-mid 50's, ~30 at warm idle.
 

U&A

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Normal driving i have never seen over 218 oil on the hotest day in the summer. I have seen just slightly over 220 when pulling 10,000lbs.

Whe dont have much for hills though.
 

Boudreaux

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Mine usually runs in the 220 range unloaded. I hit 228 yesterday with my truck pretty much maxed out on flat ground
 

Shtty6point4

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Mine usually runs in the 220 range unloaded. I hit 228 yesterday with my truck pretty much maxed out on flat ground
Do you feel that’s normal? I’m about 222 on windy hills doing about 70
 

U&A

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With the higher temp thermostats they put in the HD 6.4 the 220+ temps are normal.

You want lower temps the right way to do it is a lower temp thermostat. Maybe go with a 190 or something.

Personally im sticking with the stock one. My UOA comes back looking great so no need to change. In fact i HAD to chang my thermostat last summer and put an OEM back in.

Your oil needs to be in the 210+ range to burn of moisture and to let the add pack in the oil actually do its job.

Just an opinion from an old time syn thread bro-dozer. Dont see me there anymore tho.
 

2003F350

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With the higher temp thermostats they put in the HD 6.4 the 220+ temps are normal.

You want lower temps the right way to do it is a lower temp thermostat. Maybe go with a 190 or something.

Personally im sticking with the stock one. My UOA comes back looking great so no need to change. In fact i HAD to chang my thermostat last summer and put an OEM back in.

Your oil needs to be in the 210+ range to burn of moisture and to let the add pack in the oil actually do its job.

Just an opinion from an old time syn thread bro-dozer. Dont see me there anymore tho.
This is pretty much it right here. IIRC the 6.4 is spec'd to use synthetic oil only, which can handle higher temps anyway. Couple that with the need to run hotter to burn off condensation, and I believe the oil cooler is cooled by the coolant anyway, and your oil temp, once you're up to operating temps, will be right about in line with the coolant temp.
 
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Toddz

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I haven't had any issues and mine runs around 220 normal driving and between 230 and 255 towing the west coast mountains. I was concerned at first, but everything I saw leads me to believe the hemi likes to run warmer.
 

ramffml

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the hemi likes to run warmer.

I hate this expression because the hemi doesn't "like" anything. It was programmed/tuned to run at a range the engineers/bean counters decided it should run at. What your observations should be leading you to say, is: the hemi often runs at 220 to 250 degrees.

The question is: is that range more helpful for emissions and/or MPG, or more helpful for longevity?

My truck will exceed 250 degrees. Does that mean it "likes to run at 250 degrees"? As in, it's better for it to run at that temp? Very doubtful.

The reason I'm nit picking your use of the word "like", is because that word has subtle implications, such as "everything is happy, everything is good, there is nothing to worry about". That's a completely different conclusion than simply saying "the hemi often runs hot".

/end rant.
 

crash68

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if I'm not mistaken the 6.4 sprays the bottom of the pistons/cylinders with oil. That would cause warmer than coolant temperatures
 

buckeyexx

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I could be mistaken but I don’t believe you can run a cooler thermostat on the 6.4 since it is built into the housing. Maybe you can modify it somehow for a cooler one but just buying it that way I don’t believe you can do so.
 

Toddz

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"I hate this expression because the hemi doesn't "like" anything. It was programmed/tuned to run at a range the engineers/bean counters decided it should run at. What your observations should be leading you to say, is: the hemi often runs at 220 to 250 degrees."
I believe if you read my post again instead of just the phrase you "hate", you will see I gave the temperature range my engine runs. I said the phrase you dislike as an attempt to let the o.p. know his truck is within normal range based on numerous posts i have read.
 
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U&A

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Bottom line. For the oil and its additives to do their job it ideally……..again…..”ideally” should be right around 210 degrees.

Thats part of the reason UOA checks the viscosity at 210 among other things

anything over 210 is not really necessary but it is what it is.220 is close enough and yes part of the reason they do it is for emissions. They dont give a cr@p about how long we can make the trucks last. They want us to keep buying trucks.

For example, moly wont plate cery well under 200ish.

ZINC and PHOSPHORUS wont do their multifaceted job very well when the oil is below 200ish.

Calcium wont act as a cleaner (part of TAN) and keep your TBN up without high oil temps
 

ramffml

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"I hate this expression because the hemi doesn't "like" anything. It was programmed/tuned to run at a range the engineers/bean counters decided it should run at. What your observations should be leading you to say, is: the hemi often runs at 220 to 250 degrees."
I believe if you read my post again instead of just the phrase you "hate", you will see I gave the temperature range my engine runs. I said the phrase you dislike as an attempt to let the o.p. know his truck is within normal range based on numerous posts i have read.

But again, "normal" doesn't mean "good". That's the point. Yes all these trucks will get hot under the same circumstances so his truck is "normal" in that regard. Doesn't mean it's "a good thing to be that hot".

When you use words like "like" and "normal", it implies "nothing to worry about". I just don't agree with that implication, even if it's "normal" for the hemi to run that hot (250) it's definitely way too hot for my liking.
 

ScubaSteve178

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But again, "normal" doesn't mean "good". That's the point. Yes all these trucks will get hot under the same circumstances so his truck is "normal" in that regard. Doesn't mean it's "a good thing to be that hot".

When you use words like "like" and "normal", it implies "nothing to worry about". I just don't agree with that implication, even if it's "normal" for the hemi to run that hot (250) it's definitely way too hot for my liking.

It is my experience, not only with my 6.4, but with most engines all the way from small cars up to 50L+ diesel generators that oil temps like to sit between 200-255 depending on how hard it is being worked.

I will admit that those temps seem incredibly high, especially if you come from the old-school of small block Chevy's or other, older engines in general. My friends who race dirt track run SBC's and they start to get spooked when the coolant temps reach 215-220. The materials used in the castings of modern blocks, heads, et al are not what they used to be, in the sense that they are much purer, higher quality, and are designed with the higher temperatures that must be hit for emissions and fuel efficiency in mind.

So with that in consideration, the idea that it's too hot for your liking, may very well be the case, but that doesn't mean that its too hot for the engine's "liking". I mean really, aside from some obvious design defects, if the high temps were truly a problem for modern vehicles with all their heat blankets and plastic coverings that hold in heat, we wouldn't be seeing vehicles that routinely last for many, many more miles than we saw back in the days of conventional oil and paper gaskets, etc.

Normal changes with time...just like its now normal to have an engine that runs with a 10/10.5:1 compression ratio on pump gas, whereas back in the day 10:1 was a fairly high performance build that you needed to be running at least the higher octane fuels, and most everything in stock form was 8 or 8.5:1.
 

ramffml

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It is my experience, not only with my 6.4, but with most engines all the way from small cars up to 50L+ diesel generators that oil temps like to sit between 200-255 depending on how hard it is being worked.

I will admit that those temps seem incredibly high, especially if you come from the old-school of small block Chevy's or other, older engines in general. My friends who race dirt track run SBC's and they start to get spooked when the coolant temps reach 215-220. The materials used in the castings of modern blocks, heads, et al are not what they used to be, in the sense that they are much purer, higher quality, and are designed with the higher temperatures that must be hit for emissions and fuel efficiency in mind.

So with that in consideration, the idea that it's too hot for your liking, may very well be the case, but that doesn't mean that its too hot for the engine's "liking". I mean really, aside from some obvious design defects, if the high temps were truly a problem for modern vehicles with all their heat blankets and plastic coverings that hold in heat, we wouldn't be seeing vehicles that routinely last for many, many more miles than we saw back in the days of conventional oil and paper gaskets, etc.

Normal changes with time...just like its now normal to have an engine that runs with a 10/10.5:1 compression ratio on pump gas, whereas back in the day 10:1 was a fairly high performance build that you needed to be running at least the higher octane fuels, and most everything in stock form was 8 or 8.5:1.

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.
 
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