Diesel cooling options and ideas

[Chief_jeep]

Sounds like the insane diesel helps. A overlooked component is gearing. My jeep on 3.73's has much higher oil temps climbing grades than a friends jeep on 4.88s and 40s.

We both still hit 250 at some point at higher speed but they get there slower.

I have never derated on my gladiator on 38s climbing the sierras at 75-80mph. I have got to the upper limit of this.

I stand by removing all foam blocks, venting your hood, etc to let the underhood breathe.

I plan on doing a upgraded radiator at some point and have shifted my focus on somehow fitting a more efficient intercooler at the same time. Air temps and oil temps play a huge role in these jeeps but the coolant temp going up is the starting point to overheating. I really wish Banks would offer a intercooler, ram or cold air intake, and radiator upgrade. I would be first in line.

It definitely helps a lot! Not 25 degrees like they state but I’m asking a lot of it. It is a 15 degree improvement and to be fair it would probably be 20+ if I stayed on 40s.

I’m geared at 4.88. I’ve removed all that shit and my hood is very vented. I’m also running a cold air intake. Surprisingly, outside air temps only affect my temps by a few degrees.

I’d definitely invest in better radiator but I’m not sold on the performance of the cold case. A customer radiator setup is an option but incredibly expensive.

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[jav_eee]

You all really need to hit up the guy who does the RPM extreme JL fan controller to see if it works on the 3.0. It cools the 3.6 down a whole lot.

 

[steelponycowboy]

For what my experience is worth- I haven’t towed heavy yet with our JTRD, but with stock tires I’ve seen oil temps up to 246 going over Santiam Pass in Oregon towing our 10’ enclosed utility trailer (probably around 2500 lbs fully loaded) This was with outdoor air temps in the mid 60’s. Coolant was about 215. From my experience back when I owned a 6.0 powerstroke, ideally your Delta-T between the oil and coolant temp was less than 15 degrees. I never saw greater than 15 degrees delta-T after I replaced the oil cooler. On the 3.0 diesel in our JT, I would’ve been at 31 degrees delta-T (246-215=31)
This tells me at least one or more of the following issues are in play, specifically the efficiency of the oil cooler is poor - not rejecting enough heat from the oil into the coolant. This could be a) not enough contact surface inside the cooler between oil and coolant b) not enough flow volume of coolant or oil or c) too high ratio of coolant to oil flow volume - lack of sufficient dwell time for the oil to transfer heat to the aluminum in the heat exchanger plate, or the coolant doesn’t contact the plate adequately enough to absorb the heat. In any regard, a heat exchanger in a cooling system with a delta-T of over 30 degrees is simply not operating correctly. Oddly enough Jeep says the limitation is the cooling stack, however if that were true I would still expect better performance from the oil cooler, albeit with much higher coolant temps… All this to say I wonder if there is a different water pump in Ram applications, or a different coolant line routing design which increases the HX efficiency?

The big difference in the Ram is the cavernous engine compartment which is why the 3.0 does so well in the Ram and doesn't suffer the same issues the JT has. It was a bad choice to put the 3.0 in the JL/JT and Jeep gave up on it in the US only in 2023

 

[Sting-Gray Neutral Pres.]

I'm guessing you don't tow. I regularly tow a 3000lb trailer and have had water temps go critical, oil temps hit 269 and Trans temps go nuts towing in mountainous areas.

I do. See this picture:
https://www.jeepgladiatorforum.com/...-leftover-23-to-tow-better.80299/post-1307452

Somewhere north of 6k lbs in that thing, huge frontal area, multiple 2-3,000 ft climbs over passes. Never saw over 250 oil temp. I strongly suspect you have combined several negative factors to create a worst case scenario that is more than the sum of its parts:

1. big tires
2. high payload
3. moderate towing
4. extreme temperatures (noting the Mesa, AZ location)
5. grades

In the picture above I don't have 1 and 4, and I did fine. Nothing to be done about #4 in your case, but you can easily change #1. Basic mechanics dictates that lower RPMs = less coolant pumping and less oil pumping, significantly reducing your effective cooling. Also there's the basic physics of heavier tires.
Try going back to 33" stock Rubicon A/Ts or even 32" Willys A/Ts and see what that does for you. If you are towing a trailer, tire size won't be the limiting factor in what campsites you can get to.

 

[steelponycowboy]

To me it sounds like a combination of getting a truck built on a Friday before a 3 day weekend and extreme use case where you should have a full size. What does your truck weigh vs what it is rated for? It looks like you’re on roughly 37’s plus a living camper shell plus you’re towing 3,000lbs on the regular in extreme terrain?

Nope my camper shell weighs 352 lbs. I only tow on the highway never off road and tires are 35s. No extreme use at all.

You really should trade that in under lemon law... my god that sounds like a nightmare. I know plenty of people with 100s of thousands of miles/KMs on their EcoDiesels with no issues. I know plenty without, it is what it is when it comes to modern vehicles.

I love my 3.0, absolute torque monster while getting 30+ mpg all day long.

30 mpg must be stock. There are more issues with the 3.0 than you realize. It's why they dropped it. It still meets smog requirements and they had nothing to replace it. Still sold around the world and in Europe where smog requirements are as strict as CA.

I do. See this picture:
https://www.jeepgladiatorforum.com/...-leftover-23-to-tow-better.80299/post-1307452

Somewhere north of 6k lbs in that thing, huge frontal area, multiple 2-3,000 ft climbs over passes. Never saw over 250 oil temp. I strongly suspect you have combined several negative factors to create a worst case scenario that is more than the sum of its parts:

1. big tires
2. high payload
3. moderate towing
4. extreme temperatures (noting the Mesa, AZ location)
5. grades

In the picture above I don't have 1 and 4, and I did fine. Nothing to be done about #4 in your case, but you can easily change #1. Basic mechanics dictates that lower RPMs = less coolant pumping and less oil pumping, significantly reducing your effective cooling. Also there's the basic physics of heavier tires.
Try going back to 33" stock Rubicon A/Ts or even 32" Willys A/Ts and see what that does for you. If you are towing a trailer, tire size won't be the limiting factor in what campsites you can get to.

Im really done trying to make thus work. $35k+ in warranty repairs, 12 major breakdowns and dealers all over the country and people from Jeep telling me the 3.0 never should have been put in the JL and JT just tells me how much Jeep has struggled with diesel issues and can't seem to fix them as evidenced by the discontinued motor from the US market. All my years owning Jeeps, it's been frustrating and disappointing to say the least. Any vehicle where warranty repair costs exceed 50% of the MSRP is a total POS

 

[CrazyCooter]

I do. See this picture:
https://www.jeepgladiatorforum.com/...-leftover-23-to-tow-better.80299/post-1307452

Somewhere north of 6k lbs in that thing, huge frontal area, multiple 2-3,000 ft climbs over passes. Never saw over 250 oil temp. I strongly suspect you have combined several negative factors to create a worst case scenario that is more than the sum of its parts:

1. big tires
2. high payload
3. moderate towing
4. extreme temperatures (noting the Mesa, AZ location)
5. grades

In the picture above I don't have 1 and 4, and I did fine. Nothing to be done about #4 in your case, but you can easily change #1. Basic mechanics dictates that lower RPMs = less coolant pumping and less oil pumping, significantly reducing your effective cooling. Also there's the basic physics of heavier tires.
Try going back to 33" stock Rubicon A/Ts or even 32" Willys A/Ts and see what that does for you. If you are towing a trailer, tire size won't be the limiting factor in what campsites you can get to.

Tire size/gearing isn't the real issue here unless a person is running an extremely unbalanced combo like say 42's on 3.73's?

I did a test in my derating thread where I almost back to back (next day) tested 37's and stock tires with almost no change in the result.....in fact it felt much less comfortable with the gear spacing on the stock tires. The ambient temp was slightly different and that couple of degrees is what I attribute the change in results to.

I have also done a gear swap since and probably 25K of moderate to heavy towing after and the result is pretty much the same.....except he truck has not gone full limp since the last recall reflash for the "Emissions update".

 

[RoamingGladiator]

Nope my camper shell weighs 352 lbs. I only tow on the highway never off road and tires are 35s. No extreme use at all.

30 mpg must be stock. There are more issues with the 3.0 than you realize. It's why they dropped it. It still meets smog requirements and they had nothing to replace it. Still sold around the world and in Europe where smog requirements are as strict as CA.

Im really done trying to make thus work. $35k+ in warranty repairs, 12 major breakdowns and dealers all over the country and people from Jeep telling me the 3.0 never should have been put in the JL and JT just tells me how much Jeep has struggled with diesel issues and can't seem to fix them as evidenced by the discontinued motor from the US market. All my years owning Jeeps, it's been frustrating and disappointing to say the least. Any vehicle where warranty repair costs exceed 50% of the MSRP is a total POS

Running 37s with all my recovery gear, 30mpg all day long. Every modern engine has issues, it is what it is at this point. If I wanted a reliable vehicle I would of went with an old Toyota.

 

[Dougstdig]

1. It’s about 40k for a motor, trans and atlas with an install.
2. I’m still averaging 18.5 mpg on 42s and have over 500lb ft of torque
3. I’m not interested in a hemi (weight, space and heat issues) and motech hasn’t released their JL/JT swap yet which is what I’d do.

Not to mention…the symphony that comes out of a Late GM V8 is unmatchable by the other big 2.

 

[916WI]

Nope my camper shell weighs 352 lbs. I only tow on the highway never off road and tires are 35s. No extreme use at all.

30 mpg must be stock. There are more issues with the 3.0 than you realize. It's why they dropped it. It still meets smog requirements and they had nothing to replace it. Still sold around the world and in Europe where smog requirements are as strict as CA.

Im really done trying to make thus work. $35k+ in warranty repairs, 12 major breakdowns and dealers all over the country and people from Jeep telling me the 3.0 never should have been put in the JL and JT just tells me how much Jeep has struggled with diesel issues and can't seem to fix them as evidenced by the discontinued motor from the US market. All my years owning Jeeps, it's been frustrating and disappointing to say the least. Any vehicle where warranty repair costs exceed 50% of the MSRP is a total POS

Sounds like you got a lemon--I would have traded it off after the second breakdown. I love my diesel so far--we'll see how it tows in a month or so when I take my 16' trailer out. I moved it locally, and at 2800lbs, it wasn't even remotely stressed. I've been conscious about weight tho.
You have to realize that you're way over your payload limit. You have between 900 and 1000lbs to work with. That front bumper, the camper shell, the wheels and tires, and the hitch weight of the trailer alone have to put you right on or over. Regardless--I'd sell the thing. Take the financial hit and move on. Life is too short to deal with that kind of stress........

 

[RoamingGladiator]

Sounds like you got a lemon--I would have traded it off after the second breakdown. I love my diesel so far--we'll see how it tows in a month or so when I take my 16' trailer out. I moved it locally, and at 2800lbs, it wasn't even remotely stressed. I've been conscious about weight tho.
You have to realize that you're way over your payload limit. You have between 900 and 1000lbs to work with. That front bumper, the camper shell, the wheels and tires, and the hitch weight of the trailer alone have to put you right on or over. Regardless--I'd sell the thing. Take the financial hit and move on. Life is too short to deal with that kind of stress........

While I do not think 100-200lb over payload is a big deal, I'm surprised they are warrantying him. He's definitely over payload on a Rubicon Diesel... Its 925-935 pounds I believe depending on your package. Looks like a camper, extra fuel, camping gear I presume, him, maybe some family... he's definitely at least over payload if not significantly over.

Most dealerships would void that shit real quick. Either way, I don't think being slightly over payload should cause all those issues. Definitely a lemon.

 

[@californiajeeping]

Mishimoto confirmed their radiator does fit the 3.0l diesel.

I asked if there’s plans for an intercooler upgrade or coolant hoses and got a cold shoulder. @Mishimoto I have 4 of us with diesels that would buy coolant hoses and intercoolers right now. I’m sure there’s more on this forum.

 

[RoamingGladiator]

Mishimoto confirmed their radiator does fit the 3.0l diesel.

I asked if there’s plans for an intercooler upgrade or coolant hoses and got a cold shoulder. @Mishimoto I have 4 of us with diesels that would buy coolant hoses and intercoolers right now. I’m sure there’s more on this forum.

While I'm not really the best test case for overheating as I live in a relatively flat area at sea level, I'll be doing a few heat management upgrades this year for when I'm towing.

Supplemental Cooling System 2021-2023 Jeep Gladiator/Wrangler Diesel (bulletproofdiesel.com)
BladeRunner 3 IN Aluminum Hot and Cold Charge Pipe Kit Black | aFe POWER

Inexpensive upgrades to get better operating temps on the Ecodiesel.

 

[Chief_jeep]

Mishimoto confirmed their radiator does fit the 3.0l diesel.

I asked if there’s plans for an intercooler upgrade or coolant hoses and got a cold shoulder. @Mishimoto I have 4 of us with diesels that would buy coolant hoses and intercoolers right now. I’m sure there’s more on this forum.

Talked with someone who had a friend install mishimotos radiators and it cracked in 4 months… maybe it’s a one off situation but I’m not willing to be the the test dummy. It also frustrates me that mishimoto and cold case don’t share performance data. Sure it holds more volume but what does that do for temps.

 

[Rusty PW]

Talked with someone who had a friend install mishimotos radiators and it cracked in 4 months… maybe it’s a one off situation but I’m not willing to be the the test dummy. It also frustrates me that mishimoto and cold case don’t share performance data. Sure it holds more volume but what does that do for temps.

Mishashitymoto doesn't have a good rep on the Z car forum. No body will buy their products because of issues like that. There has been about a half dozen radiators that leaked. CSF has their issues too. They last about 18 months to 2 years before they start to leak.

 

[biodiesel]

Its a toy, not a truck, the 1/4 ton frame in the front with the fabbed up 1/2 ton frame in the back adds to the issues. It is a total turd towing but I believed the Jeep hype with their overstated towing numbers.

I'm not expecting too much from a mid-sized truck in terms of towing. I'll use the Gladiator to haul firewood off the mountain, but that's about it. I'm guessing that a small load of firewood with trailer would be no more than 3,500 - 4,000 lbs of towing at low speeds.

Besides, rumor from well placed sources in Jeep and Ram say that the JT will be done with the 2026 model year and will be replaced by a new true 1/2 ton mid sized Ram truck. We are all about to be driving dinosaurs on the way to extinction

I love my dinosaur.

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