So disappointed in this Diesel platform; wish there was a return policy.

[aj8544]

One thing to note, as someone without a dog in this fight (again, because mine is a low tow rating manual), the gas automatic Rubicons have the second highest tow ratings of all Gladiators, next to the Sport ( or Sport S) Max Tow, at 7000 lbs vs 7650. So gas auto Rubicons make pretty decent tow vehicles as well.

Exactly… When I bought my Rubicon gasser I knew I would be towing. But I also wanted offroad capability. In my opinion the gas Rubicon with auto trans is still the most versatile and dare I say best value trim level for someone who needs to do truck duty AND offroad jeep stuff.

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[ShadowsPapa]

Same issue with current Yamaha outboards, people don't run them hard enough and the rings do not seat and you end up with fuel diluted oil, very hard to convince people to take a brand new motor and run it hard at wot when it is brand new.

Too much telephone game here.
There are "dino oils" that prevent wear, or have better wear protection than synthetics, so the fact an oil is synthetic or not isn't the issue. It's the whole package - the base AND the additives together that determine wear protection.
There are non-synthetic oils that actually prevent wear better than many synthetic oils. So blaming it on synthetic base is baseless. People over-simplify or read things wrong, or just plain take a tidbit from here or there and draw their own conclusions.

Running at WOT doesn't break it in - LOAD does. You need to load the engine, not just run at high RPM. And high RPM actually does more harm that good on an engine not ready for it.
Full throttle in itself is no load and does not force rings against the cylinder walls.
It's the PRESSURE DIFFERENCE between above the rings and below the rings that forces them out. Look at how rings are "cut". An end view is NOT a square. There are chamfers, notches, etc. Those are designed to take advantage of the differences in pressure above and below and the directional movement of the rings to force them out against the cylinders.
LOAD the engine - high loads, not high RPM. NOT lugging, but don't wind it up tight with no load either. Load not speed.

I could paraphrase here myself - it's really hard for REAL factory-trained mechanics with decades of engine experience to convince others the facts about break-in and oils.
People are reading things on forums that other people read and tried to repeat - but it's not exact word-for-word and like that old telephone game, by the time it reaches the 5th copy it barely resembles the original.
Sorry, but I really have to laugh when I have the books from famous engine builders over the years, a fellow who worked on helping to develop the Isky cam, a guy who worked for GM, and a book from Perfect Circle themselves about break-in, oils and so on.

If everything is right - the cylinder wall finish, the cylinder wall being a perfect circle (machined properly and with after-market builds, use of torque plates and so on) and if the rings are right - the gaps proper, etc. then the rings are seated and broken in within hours. Not months, not thousands of miles (it used to be about 2,000 miles but that would be the very most even today, more like 500 or less today)

Some of this is older as ring technology and machining methods have improved over the years to drop the number of miles down substantially.

The last 4.0 I built used NO OIL in the first change period - about 500 miles, and no oil at all after that - about 3,000 miles. I do not have to add oil between changes, 33,000 miles later the plugs still burn almost white and clean. I simply drove it out of my shop, followed the procedure I was taught in college and that was echoed in the books I have, and drove it like normal. Not afraid to load it, no high RPM without load, no lugging.

This is from a company that makes piston rings and other engine parts -

 

[ShadowsPapa]

Power is a measure of force times speed. essentially torque x rpm = power.
Torque is a measure of force only.

To go up a hill at speed, you need power.
A diesel makes a lot of torque (and power) low in the rev range.
A normally aspirated gas engine makes less torque, but can spin faster. So it can make similar power by turning faster and depending on gear reduction to increase the torque.

Power is power.

100 ft-lbs of torque at 1000 rpm = 50 ft-lbs of torque at 2000 rpm.

They will both pull a trailer up a hill at the same speed.

They will also generate the same excess heat. (diesels can be more thermodynamically efficient than gas engines. So they make less waste heat per hp. But auto engines aren't really designed to maximize that)

So regardeless of the engine. Making power requires dumping heat.

One other thing to remember. Wind resistance increases as a square function. Resistance is a measure of force. Remember that power is force times speed.

So the POWER necessary to overcome wind resistance increases as a CUBED function of speed.

That means that going 60 mph requires 3.375 (!!!!) times the power as it takes to go 40 mph!!
Let that sink in for a moment.
(60/40 = 1.5, 1.5^3 = 3.375)

At highway speeds the majority of the drag is aerodynamic, not a result of rolling resistance. (Which increases linearly, so the power required increases as a square function)

The bottom line is that driving a vehicle at 60 mph requires the vehicle to dispose of about 3 times as much heat as driving at 40 mph. Its a pretty steep curve.

One last thing. At various times in my life I've roadraced and autocrossed cars.

For a car to survive on a race track it has to shed a lot of heat. The motor makes near maximum power a lot of the time. Then all that energy is dumped into the brakes. Engine oil gets hot, coolant gets hot. So radiators need to be big. Brakes get hot, so they need to be big. Differentials . . you get my point.

In autocrossing its an entirely different situation. An autocross run takes about a minute. So heat is an absolutely non-issue. Radiators can be small. Transmission oil coolers are nonexistent. Brakes can be small and light since they will barely be warm at the end of a run.

Its all about heat.

OK. I've beaten this horse till its hamburger. I hope this was helpful to some.

Don

LOL - it worked. I triggered some logic, and for the geeks and Bill Nye's of the forum to come forward with some science.

Torque is the ability to do work
Horse power is the measure of work done. (think of the origin - a horse pulling a load over time)
Wind resistance increases exponentially, the slope shoots up quickly over about 60 mph.
A trailer that presents a large front is like pulling a parachute behind you in a way - or a big sail.
Burning fuel results in heat, some of which is converted into mechanical motion, the rest has to be disposed of. The engine creates xxx BTUs of heat for a given condition, and the cooling system has to be capable of disposing of or removing those and more. More load at a higher speed means more fuel burned and the side effect of more heat to remove.

The testing of these for max towing vs heat, etc. etc. was done at 40 - not 60, not 65, not 70, so trying to pull that load at 65 and then talking about the heat produced is ignoring the testing behind these. The increase in "wind resistance" is steep - making it worse is the sail sticking up behind the truck.

So maybe the diesel is actually meeting Jeep's expectations, it's just being pushed too hard as far as load vs speed vs incline is concerned. It was tested full load up hill yes but at 40, not 60 or 70.

 

[CreepyJeepy]

LOL - it worked. I triggered some logic, and for the geeks and Bill Nye's of the forum to come forward with some science.

Torque is the ability to do work
Horse power is the measure of work done. (think of the origin - a horse pulling a load over time)
Wind resistance increases exponentially, the slope shoots up quickly over about 60 mph.
A trailer that presents a large front is like pulling a parachute behind you in a way - or a big sail.
Burning fuel results in heat, some of which is converted into mechanical motion, the rest has to be disposed of. The engine creates xxx BTUs of heat for a given condition, and the cooling system has to be capable of disposing of or removing those and more. More load at a higher speed means more fuel burned and the side effect of more heat to remove.

The testing of these for max towing vs heat, etc. etc. was done at 40 - not 60, not 65, not 70, so trying to pull that load at 65 and then talking about the heat produced is ignoring the testing behind these. The increase in "wind resistance" is steep - making it worse is the sail sticking up behind the truck.

So maybe the diesel is actually meeting Jeep's expectations, it's just being pushed too hard as far as load vs speed vs incline is concerned. It was tested full load up hill yes but at 40, not 60 or 70.

100% agreed here. The engineers were likely focused on the test itself, and passed the test. We understand that. My comparison was to my 4.0L tacoma, which would hit the same hill, at faster speeds, with significantly less heat, no pulling of power, with 1/2 torque, with a lift kit, and much more weight did not have this issue. I could go 100% throttle up that hill in the gas taco with zero issues.

I'll slow down for sure, and modulate throttle to prevent roasting the turbo!

Also, I'll be honest the jeep is way cooler, way more American (important to me) and way more fun to drive than the Tacoma. I don't want to get rid of it, I do indeed love it, I just need it to run a bit cooler.

This post was looking for cooling options; thus far I haven't learned much on that front, but....

I did learn that the part numbers for the radiator's might be the same though. So I am wondering if a radiator dealer would like to test fit an aftermarket radiator in my Jeep 3.0? It may not work due to intercooler, trans cooler placement.... But if it does work it may help reduce temps...

 

[ShadowsPapa]

100% agreed here. The engineers were likely focused on the test itself, and passed the test. We understand that. My comparison was to my 4.0L tacoma, which would hit the same hill, at faster speeds, with significantly less heat, no pulling of power, with 1/2 torque, with a lift kit, and much more weight did not have this issue. I could go 100% throttle up that hill in the gas taco with zero issues.

I'll slow down for sure, and modulate throttle to prevent roasting the turbo!

Also, I'll be honest the jeep is way cooler, way more American (important to me) and way more fun to drive than the Tacoma. I don't want to get rid of it, I do indeed love it, I just need it to run a bit cooler.

This post was looking for cooling options; thus far I haven't learned much on that front, but....

I did learn that the part numbers for the radiator's might be the same though. So I am wondering if a radiator dealer would like to test fit an aftermarket radiator in my Jeep 3.0? It may not work due to intercooler, trans cooler placement.... But if it does work it may help reduce temps...

As another member pointed out in a totally unrelated thread - the engineers are stuck - total efficiency and doing the very best vs. vibration, noise, feel, etc. - there's a term for it but I've only had one coffee so can't pull it out of my head right now. They must build for the market, the buyer, the consumer, and if it's even a tad too loud, they'll go to a quieter vehicle even if that vehicle has other drawbacks.
Chrysler had to make subtle changes to AMC's 4.0 because buyers of the Grand Cherokee complained about the engine being noisy! So they added ribs to the side of the block and changed the timing chain setup and added a snubber to remove chain slack. (sorry, ladies, but I bet it wasn't guys complaining, I loved the "truck engine" sound! but the Grand Cherokee was selling like hotcakes to women)

Anyway, so if a better or larger radiator made more noise via the air moving through, or if there was more FAN noise - nope, the truck wouldn't get it at the factory. Air box/filter area - engineered not just for power - but a compromise to reduce sound. Buyers these days gripe about noise. I love the sound my engines make sucking air in as fast as they can. Most folks don't.

 

[redrider]

Drawing upon motorcycle experience, a product such as Waterwetter may lower the temps 10 deg or so but the aforementioned testing speeds are telling. Adequate cooling at 40 mph; Above that and loads/heat generation becomes taxing. As I have learned over the decades, there is a purpose and use for homework. I am the salesman's nightmare.

 

[ShadowsPapa]

Drawing upon motorcycle experience, a product such as Waterwetter may lower the temps 10 deg or so but the aforementioned testing speeds are telling. Adequate cooling at 40 mph; Above that and loads/heat generation becomes taxing. As I have learned over the decades, there is a purpose and use for homework. I am the salesman's nightmare.

LOL - yeah, I generally go in knowing more than the sales people do. I know the specs when I go in. And you should see me when I take a vehicle into the dealer for work - I explain to them the problem, and usually what the solution is - sometimes even detailed trouble reports. Last time they huddled around the papers I gave them and one came back to me and asked "how did you get this? This takes dealer tools to get". LOL - trained auto tech, and I have some of those tools.
They've actually gotten to not question things when I take something in. I've done a lot of the work for them. A few months ago they even asked if I had any more information on a problem we'd been working on.

 

[Markkabureck]

Is yours gas or diesel?

Diesel

 

[yolo]

If that would work, the Jeep engineers would have already done it.

If you read the post I mentioned earlier, the Jeep cooling engineers said the hood was off limits.

 

[dcmdon]

One other thing re gas vs diesel and towing.

If its 50 deg out and you are towing a 4000 lb load on a flat road, there is no doubt that the diesel will FEEL BETTER. The torquey nature of the diesel makes it an inherently better motor for towing.

But that assumes that the diesel isn't pushing the thermal limits of the cooling systems of the vehicle.

Identical engines in a different installation, the diesel version may do better. In a Ram pickup with all that under hood space and a huge grill allowing plenty of room for a big radiator and charge cooler, the diesel might end up with a higher tow rating.

Shadowpapa - re running a new engine under load, the way I learned it was that you needed high manifold pressure. That means a load with a large throttle opening. You want to maximize combustion chamber temps and pressures. This is because rings work by allowing combustion pressure behind them and that forces the rings against the cylinder walls.

It isn't the spring tension of the rings that creates most of the seal. Its the pressure itself.

You want this pressure intermittently so the rings seat and then everything has a chance to cool, then repeat.

Ironically that's why running the car on a race track is an ideal break in regiment. High load for a short time followed by idle or overrun. Then heavy load again. In contrast to pulling a trailer at highway speeds which is long intervals of high load.

 

[AXISJT]

It seems to me like there's a lot of mixed reviews on towing with the diesel.

I think a lot of it comes down to really sitting down and thinking about what you want and what you need the gasser can definitely tow more without issues apparently but that seems to be an only certain situations, so if there's a situations you think you will find yourself in then you should go with the gasser.

I went with the diesel because my towing situation is a boat to and from the lake no extreme hills or anything like that and I personally think in basic towing situations like that the diesel is more comfortable to tow with.

I do think there will be some aftermarket solutions that can help with the cooling issue I'm also curious if any of you guys think putting inner fender liners with the venting in would help cool as well as maybe some scoops.

 

[dcmdon]

I went with the diesel because my towing situation is a boat to and from the lake no extreme hills or anything like that and I personally think in basic towing situations like that the diesel is more comfortable to tow with.

I think you are absolutely right. At the limit, the gas engine can tow more.

But below the limit, the diesel with its broad flat torque curve will feel better, without the need to constantly drop down a couple of gears to maintain speed up a grade.

 

[ChimeraJT]

This thread has been a super interesting read. My biggest takeaway is that Jeep should have put a note in the manual explaining the parameters of their towing test (only 40mph), and maybe done a bit of physics explanation for why you shouldn't expect to haul ass up an 7-9% grade in 100+ weather towing at limit (dcmdon should be writing the owners manuals )

Personally, I don't plan to tow much except once in a blue moon. I will mainly be using mine as a DD/exploration/utility vehicle so the towing limits aren't as big of a deal to me, but I also live in Texas where we can get weeks of 100+ temps at a time, so I will be on the look out for an aftermarket radiator just to make it easier on my engine due to regional climate.

 

[Imbuere]

Mine gets hot too on steep grades but i am towing way more . My camper is a 20 foot nobo that is 24 feet long and is 5k lbs louded . Also way more truck weight 4 people and a need full . On a scale i was about 11500 loaded . Also i did have to floor it on a couple steep grades but it maintained 75 mph and i am on 37s . Also look into the banks daringer for a good upgrade option , i do not have it yet

Now that’s the kind of Jeep porn I come here for!

 

[ShadowsPapa]

Shadowpapa - re running a new engine under load, the way I learned it was that you needed high manifold pressure. That means a load with a large throttle opening. You want to maximize combustion chamber temps and pressures. This is because rings work by allowing combustion pressure behind them and that forces the rings against the cylinder walls.

It isn't the spring tension of the rings that creates most of the seal. Its the pressure itself.

You want this pressure intermittently so the rings seat and then everything has a chance to cool, then repeat.

Ironically that's why running the car on a race track is an ideal break in regiment. High load for a short time followed by idle or overrun. Then heavy load again. In contrast to pulling a trailer at highway speeds which is long intervals of high load.

Yes, that's pretty much what the graphic I posted was indicating. It's the difference in pressure - high load, high combustion pressure compared to below. That flexes the rings. I mentioned the shape or profile of the rings because I have another graphic that shows how ring shape works with the pressure to flex the rings out. The rings generally speaking aren't a square profile like in the 40s and earlier. They are designed so that the pressure differences between top and bottom, behind the ring compared to the outside, that is the force that seals.
High RPM itself, taking it out and just winding it up doesn't cut it. So going down I70 at 6,000 RPM won't do squat to help the rings, but loading it up and backing down - that's the break-in process.
Most books do say no trailer towing for xxxx miles. Vary the speed, no sustained idle, no sustained high speed. Yeah, take the thing to the track.

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