Operting temperatures

[Big BLU]

My TBSS ran at 205, I threw in a 160 stat and ran ~180. Worked fine. Cammed it and long tubes and was getting early 20 mpgs from less than 18 prior. Still not understanding this super hot drive trains are a good thing. I got the fluids deal. But the components and fuel economy.???

 

[SD Rebel]

My TBSS ran at 205, I threw in a 160 stat and ran ~180. Worked fine. Cammed it and long tubes and was getting early 20 mpgs from less than 18 prior. Still not understanding this super hot drive trains are a good thing. I got the fluids deal. But the components and fuel economy.???

From what an automotive engine engineer told me, most modern engines are designed to run at about 220F - 230F for the best overall performance and efficiency, that running them cooler actually reduces that efficiency.

My BMW for example has four cooling modes. The Eco mode keeps the coolant temp at 227F, most often at highway speeds at steady throttle. It's full cooling mode happens at stop lights and at idle, which is about 207F.

 

[Earl801]

OK, not entirely scientific, but this information may help. I had to run a few loads of gravel over the weekend, up a 6% grade for around 10 miles, where load weight estimated around 8,000 to 8,500 lbs. Ambient temp was around 40 degrees and I was in tow mode. I run Penzoil full synthetic and my 2019 Ram 1500 Laramie Sport has around 13K miles on it, powered by a 5.7 HEMI.

First Load

• Ran 4,200 RPM, which resulted in 60 MPH.
• Engine oil reached 260 degrees about 6 miles up the hill and held there.
• Coolant reached 225 degrees and held there.

Second Load

• Ran at 3,600 RPM, which resulted in 50 MPH.
• Engine oil reached 260 degrees about 8 to 9 miles up the hill and held there.
• Coolant reached 225 degrees and held there.

Third Load

• Ran 3.200 RPM, which resulted in 45 MPH.
• Engine oil reached 254 degrees at the top of the hill (and was still increasing prior to cresting the hill).
• Coolant reached 225 degrees and held there.

My conclusion is that, these engines are engineered to reach an engine oil temp 260 degrees and hold there, depending on the engine load requirements. At no point did the power derate, or the speed drop off, or any warning lights appear. I thought it was interesting, though, that the analog temp gauge didn't move at all throughout any of these trips. It stayed just left of center the entire time.

By the way, I have a boat with a GM Marine 6.2L Super Charged LSA. It doesn't matter what conditions I run it in, it runs at 210 degrees coolant temp. I don't have an engine oil temp gauge so can't tell you what that runs, but I think these newer engines just run hotter than older engines.

Hope this helps.

 

[jdefoe0424]

It's not just running at that temperature for maximum fuel efficiency...it does help though as the heat lost through the cylinder and head is less as temperature gradient is less.
It's also for emissions; combustion and cylinder temperatures and pressures have a pretty big effect on how complete the combustion process is and resulting emissions.

Sent from my Moto Z (2) using Tapatalk

 

[Krootz]

I almost had a stroke when I saw my dash after 100 miles in my new truck. Glad I came here and ran through the comments. Didn’t expect these temps to be normal

 

[User_3336]

Yeah, these engines run HOT! I've seen the coolant temp up to 226.

I almost had a stroke when I saw my dash after 100 miles in my new truck. Glad I came here and ran through the comments. Didn’t expect these temps to be normal

 

[User_3336]

Not a good idea. Then the active grille shutters would not be operating properly.

Can't we just throw in a cooler t-stat?

 

[Azhar]

Was around 225 degrees before the dealer update. Now at 204 degrees afterwards

What type of update? My coolant temperature reached 226 before the fan operate at high speed

 

[Fed372]

Towed today in the 90 degree heat. 70mph. Saw oil temps sitting at 235 to 245 with uphill pulls.

2020 1500 5.7 4x4 Larime

 

[silver billet]

These engines were engineered in early 2000's. They run hot now, but "engineered to run hot" is a bit of funny way to say "pushing the engine to the breaking point to keep the EPA happy".

I put in a 180 thermostat 2 years ago and it completely changed operating temps for the better. Also removed all but 2 rows of my active grill shutters.

My engine now tows at 220, which is where it used to cruise while empty. Empty I get 188 on the coolant and 195 on the oil.

Heat kills. It fatigues the engine as well as the oil.

I live in very cold winter conditions and have no trouble building heat in the winter either. 180 thermostats used to be common years ago, you can use them in our trucks without worry.

The best thing you can do for the life of your engine, is to run it cool and run a thicker oil. All this stuff about "engineered to run hot" misses the mark. Yes the engine is running at the target temps so in that way the numbers we're seeing from factory are "normal", but there is no question that thicker oil and cooler temps are far better for it. If you lose even 1 MPG because of those combined changes I'll eat my shirt and yours too. The changes help corporate ram keep their numbers better but individually our trucks are worse off.

 

[Oldphart]

I almost had a stroke when I saw my dash after 100 miles in my new truck. Glad I came here and ran through the comments. Didn’t expect these temps to be normal

I was OK with everything but the trans temp. All my other vehicles like the trans around 160 or so. Used to it now that I know that's what the trans is designed to run at.

 

[Humphammer]

I just changed the oil and filter in my 2024 Ram 5.7 Hemi for the first time yesterday. Factory fill had 4,752 miles on it. From a cold start I drove the truck 20 miles round trip to warm up the oil so it would drain out more completely. It was 68 degrees outside, windows down and sunroof open and the trip was mostly on a flat road with cruise set at 60. As I pulled back in my driveway oil temperature was 221, trans 183, coolant 207, oil pressure was 48 and I got 20.4 MPG.

Changed the oil and refilled with Pennzoil Ultra Synthetic 5W-30 and Fram oil filter XG 10060. Took the exact same route with the only difference it was now 72 degrees outside. As I pulled back in my driveway oil temperature was 214, trans 185, coolant 205, oil pressure was 53 and I got the exact same 20.4 MPG. Other than a better oil pressure and slightly lower oil temperature which with fresh oil with a higher viscosity is to be expected everything was basically the same.

Other than trying to get my large hands through the opening to the filter the oil change was not difficult. I did use an oil udder on the filter (which worked flawlessly) and replaced the drain plug with a Fumoto F106N. Other than just a few drips from the filter housing after I removed the oil filter landing in the drain pan, I didn't spill any on my driveway.