Diesel Coolant Temp

Plongson

Well-Known Member
First Name
Paul
Joined
May 8, 2020
Messages
74
Reaction score
73
Location
So. Utah
Vehicle(s)
2020 Wrangler Rubicon JL Diesel
Occupation
Retired engineer and business owner. Vibration analyst, reliability specialist.
Vehicle Showcase
1
Have you noticed the running coolant temp of the new JL 3.0 diesel? 205°f-225°f
I know that is not excessive, but I'm use to all my diesels (Cummins and John Deere tractors etc) running no more than 190°f. I suspect it is all to meet emission standards and keep the DPF nice and warm, but it sure would have been nice to have a cool running diesel engine...Oh well, it is what it is...

JFYI...I got stuck in a rollover accident traffic jam on the 95 North in Las Vegas for one hour the other day when the ambient was 105°f, and the coolant sat very comfortable at 205°f with the AC going the whole time.



Advertisement



 

Oilburner

Well-Known Member
Joined
Dec 20, 2019
Messages
152
Reaction score
252
Location
Memphis
Vehicle(s)
Jeeps
I have notice this too, seems all the newer engines run more hot for emissions -
 

WXman

Well-Known Member
Joined
Mar 1, 2017
Messages
2,406
Reaction score
2,064
Location
Central Kentucky
Vehicle(s)
2018 Wrangler Unlimited
Occupation
Meteorology and Transportation
Every diesel I've ever seen has run above 200F because it's a necessity. Compression ignition relies on heat. There are no spark plugs. Gotta' generate heat to properly burn the fuel.
 

Fredski007

Member
First Name
Fred
Joined
Jan 10, 2020
Messages
21
Reaction score
26
Location
Arizona/ Ohio/ wherever?
Vehicle(s)
2020 JLUD I 2018 Dynamax DX3 motorhome
Occupation
Retired
Have you noticed the running coolant temp of the new JL 3.0 diesel? 205°f-225°f
I know that is not excessive, but I'm use to all my diesels (Cummins and John Deere tractors etc) running no more than 190°f. I suspect it is all to meet emission standards and keep the DPF nice and warm, but it sure would have been nice to have a cool running diesel engine...Oh well, it is what it is...

JFYI...I got stuck in a rollover accident traffic jam on the 95 North in Las Vegas for one hour the other day when the ambient was 105°f, and the coolant sat very comfortable at 205°f with the AC going the whole time.
Ran several trails in Moab yesterday, 4 low and just crawled over most stuff, never went over 207, drove for hours!

075CC7BD-5C92-4D4B-8412-1552CDE775FE.jpeg
 

JLDIESEL

Well-Known Member
First Name
Kyle
Joined
Jul 27, 2019
Messages
153
Reaction score
359
Location
California
Vehicle(s)
JLURD
Any updates on what the norm is? I am especially interested in those with bigger tires. I see 210-220 as the norm and crept up pretty high today in 110 degree weather
 

AZ-Chris

Active Member
First Name
Chris
Joined
Mar 24, 2020
Messages
26
Reaction score
26
Location
Arizona
Vehicle(s)
JLWURD
I’m seeing 212 degrees after running 85 mph for a couple of hours on I-90 crossing SD & WY
 

Gorilla57

Well-Known Member
Joined
Jan 3, 2019
Messages
139
Reaction score
114
Location
Chandler AZ
Vehicle(s)
2019 JLUR Mojito
I know mine is a Ram with the 3.0, but hit 225deg coming home from Flagstaff. I was going up the hill out of Camp Verde and having to get on it a bit to get around slower traffic. At the top of the hill is when I hit that number, but temps dropped rapidly after we started going down the back side.
 

Oilburner

Well-Known Member
Joined
Dec 20, 2019
Messages
152
Reaction score
252
Location
Memphis
Vehicle(s)
Jeeps
Today mine reached 222 deg (coolant)
It was 91 outside & I was climbing an 11% grade for 2 miles tho ;)
 

Dasher320

Well-Known Member
First Name
Dave
Joined
Jan 18, 2020
Messages
112
Reaction score
194
Location
Atlanta
Vehicle(s)
1986 CJ7, 2003 TJ, 2020 JLUR
Occupation
Pilot
Vehicle Showcase
3
I hit 239 degrees pulling a travel trailer from Pueblo over to Gunnison. I was watching the transmission temp--that's not a problem. It's disappointing because the Jeep engine could pull a 3000# trailer over those passes at 65 mph no problem, but the coolant system can't handle it. I backed off to 40-45 mph up the passes and turned off the AC and the temp stayed around 217.
 
OP
Plongson

Plongson

Well-Known Member
First Name
Paul
Joined
May 8, 2020
Messages
74
Reaction score
73
Location
So. Utah
Vehicle(s)
2020 Wrangler Rubicon JL Diesel
Occupation
Retired engineer and business owner. Vibration analyst, reliability specialist.
Vehicle Showcase
1
  • Thread starter
  • Thread Starter
  • #11
The issue seems wide spread and not limited to just a few units...Makes me wonder if it's designed into the emission control or if they are really not able to cool themselves down...if that's the case, there might be a recall for engine temp.

Like I said earlier, all my Cummins and John Deere engines run at 180°f and never pull more than 190°f. These little motors are running way too warm IMO.
 

Sydwaiz

Well-Known Member
First Name
Mark
Joined
May 11, 2020
Messages
47
Reaction score
46
Location
Torrance, CA
Vehicle(s)
73 CJ-5 soon to be JLURD
I've been doing a little reading while waiting for mine to arrive and it appears that the Ecodiesel uses a water cooled turbo charger. I'm willing to bet dollars to doughnuts that this directly affects the coolant temps especially under high boost where the turbo is generating the most heat.
 

Compression-Ignition

Well-Known Member
First Name
Roy
Joined
Nov 12, 2019
Messages
427
Reaction score
428
Location
Eastern Washington
Vehicle(s)
2020 JLUR 3.0 Diesel (FIRECRACKER RED), 2020 6.7L F350, 2011 QX56, 2005 5.9 Cummins
Well someone needs to find a thermostat with a lower opening threshold and install it. I'm wondering if the whole system will freak out trying to compensate? Just seems crazy that these things were most likely designed to run this hot for emissions purposes, yet it might be detrimental to engine longevity running so hot.

I also want to know if these temps that have everyone worried are actually dangerous? I know conventional wisdom says yes, but a few things have changed over the years. Who's got an FCA engineer buddy that we can pump for information?
 
OP
Plongson

Plongson

Well-Known Member
First Name
Paul
Joined
May 8, 2020
Messages
74
Reaction score
73
Location
So. Utah
Vehicle(s)
2020 Wrangler Rubicon JL Diesel
Occupation
Retired engineer and business owner. Vibration analyst, reliability specialist.
Vehicle Showcase
1
  • Thread starter
  • Thread Starter
  • #14
If you watch the digital offroad gauge, it changes VERY fast depending on load. It will go from 225°f to say 205°f in just a few seconds and if you pull over it drops like a rock...unusual to say the least for coolant temp to change that fast. Now if you watch the analog gauge on the dash, it never changes, it's very steady and does not arouse any worries.

Conventional wisdom says they should use the same sender, but who knows.

Bottom line, if these engines are really getting this warm and enough people bitch (and there are failures...) we might see a recall. Too bad some member with a radiator shop can't make an oversize radiator and see if it controls the temp better.

These suckers just run too dang hot for my liking...I saw 230°f today running the AC pulling a grade empty with 100°f ambient. It didn't come down until I backed off and threw less fuel at it. Very curious indeed.
 











Top