3.6 Engine - Now I understand the power issue

[ShadowsPapa]

when I posted about my experience with the 3.6 in a Grand Cherokee driving across the Northwest.

Had you posted about a Gladiator instead of the WK2, it would be an apples to apples comparison - tune, including transmission tuning/shift points, gear ratios, tire sizes and so on...........
I frankly would have though the Grand Cherokee to do better than the JT - but then, it's been 2 years since we have owned one with the 3.6
MPG? The GC wins hands-down. And one I drove, a loaner, blew away any GC we had ever owned. I had to look again to verify it was the 3.6
For some reason that one had a lot more guts! I was crazy different than ours. Maybe the Trailhawk is different?

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[biodiesel]

If they install the Hurricane in the Gladiator I will buy one. I truly think that would fit my needs.

I'm actually surprised we haven't seen the Hurricane go into more platforms. Chrysler first announced the Hurricane engine back in 2013. It took 10 years before it actually was put into a vehicle, and Stellantis has slow walked the Hurricane ever since. I remember when the Hurricane was supposed to be Chrysler's answer to Ford's EcoBoost engines.

 

[Mr Miami]

Had you posted about a Gladiator instead of the WK2, it would be an apples to apples comparison - tune, including transmission tuning/shift points, gear ratios, tire sizes and so on...........
I frankly would have though the Grand Cherokee to do better than the JT - but then, it's been 2 years since we have owned one with the 3.6
MPG? The GC wins hands-down. And one I drove, a loaner, blew away any GC we had ever owned. I had to look again to verify it was the 3.6
For some reason that one had a lot more guts! I was crazy different than ours. Maybe the Trailhawk is different?

I can't complain about the mileage. I ended with about 22MPG overall on a trip of 1,700 miles in 6 days. I'm sure others were getting less. A lot of mountains and altitude. Original trip was just a "short" 3 day trip from Miami to Lima Peru to go to my mother-in-laws 80th birthday celebration. But coming back, last Saturday night after the party, it was like 45k American Airlines points to fly back to Miami but only 22k to fly to Denver even though the flight connected in Miami (go figure). I was still missing 3 states (I had been to 47 except SD, MT, and HI) so I thought, what the hell, let's spend a week up there and see some stuff we have never seen (Chimney Rock, Mt. Rushmore, Sturgis, Badlands, Old Faithful, Moon Crater National Park, etc. among others). Then the best deal I could find was dropping the vehicle off in Spokane WA (about $700 for the 6 days) and take the flight from there on Saturday evening to be back on Sunday morning in time for the Miami Dolphins game at 1PM on Sunday.

Yea, my wife is patient with me after 25 years with what she still refers to me as a crazy American. But looking back, the 3.6 did what it is supposed to do at 22MPG.

 

[biodiesel]

be back on Sunday morning in time for the Miami Dolphins game at 1PM on Sunday.

That was a rough game if you're a Dolphins fan.

 

[Mr Miami]

That was a rough game if you're a Dolphins fan.

Yea, it was a sore loss. They slipped some sand in the Vaseline.

 

[ericw.]

Links, please, so we see what you are seeing.
My gut tells me, knowing the Wrangler side of things, they are panicked over temps like 220-230



Actually, it is. Especially for transmission temperatures. The book even states as much to control transmission temperatures. For engines it makes sense as well as it's all about that load vs. throttle vs. RPM sweet spot for heat rejection. So it's "a thing" - use manual mode. It's there for multiple reasons, one is to control heating.

Funny thing is - you are the only one on the Gladiator side I see complaining about heat, other than one guy who insists anything over 220 is not normal and is dangerous. (bunk)
The Gladiator is rated to tow and has a payload rating well over the Wrangler - so if heating was an issue, I'd expect the JT people to be bitchen' up a storm more than any Wrangler owner.

Remember, the way things are rated is the SAE testing (and what engineers deem ok with a buffer based on supplier input) and such testing isn't for speeds of 60 mph on extreme inclines. So if you are trying to pull full payload or trailer capacity (likely ignoring the frontage calculations) and expect to keep up 60+ mph - what do you expect??

OF course what no one reveals when talking heating is - how is it modified? Tires? Added weight? Winch up front blocking air? No one admits that they already almost hit their max payload with steel bumpers, sliders, winch and winch plate, a bar and lights that partially block the grill........

Is your Jeep stock? Fully?

I have no issues with trans temp. It's rock solid. Seems unreasonable to demand manual shifting in any modern automatic vehicle, but admittedly I have not read the owners manual and can't confirm or deny.

My trailer is a measly 2360lbs on the scale when loaded for 3 weeks.. and more often it's not loaded for 3 weeks. Even without the trailer, the same symptoms persist.

The engine is completely stock. I've tried a number of things with the 3.6 and using JScan to manually turn the rad fan on high during hill climbs helped slightly. Otherwise, everything else I've tried made no noticeable difference.

Replaced thermostat 3 times.
Replaced water pump
Oil cooler
Radiator twice, including testing the Mishimoto radiator.
Removed my winch to see if air blockage could be the problem
I even created stiffer radiator shrouds to force wind through the radiator, making sure it's not escaping around the radiator.

After my last trip through NV, ID, UT, CO, and the 17 hour drive home.. I picked up the Eco Diesel the day after I arrived home.

I already have the S&B hood scoops sitting in my office, along with a number of other mods. I think it will serve my use better, and maybe with a tune, have plenty of torque to pull mountain passes with comfort.

 

[biodiesel]

Yea, it was a sore loss. They slipped some sand in the Vaseline.

As a Chiefs fan, I have a soft heart for Tyreek Hill. I was hoping the Dolphins would get to the playoffs this year.

 

[biodiesel]

After my last trip through NV, ID, UT, CO, and the 17 hour drive home.. I picked up the Eco Diesel the day after I arrived home.

You'll love the EcoDiesel.

 

[ericw.]

You'll love the EcoDiesel.

So far I'm already enjoying it much more than the 3.6. It drives on the highway and over Donner Pass with ease, like a civilized vehicle should. I even passed a few cars on my test drive up I80 just to see if it could and it wasn't a problem.

It's not a rocket ship but still a big improvement and coolant temps seemed unfazed in my tests so far.

I think a tune and 4.56 or 4.88 gears will hopefully keep it driving like stock once I add some extra weight to it.

Both vehicles are on 35" tires currently.

 

[ShadowsPapa]

I have no issues with trans temp. It's rock solid. Seems unreasonable to demand manual shifting in any modern automatic vehicle, but admittedly I have not read the owners manual and can't confirm or deny.

My trailer is a measly 2360lbs on the scale when loaded for 3 weeks.. and more often it's not loaded for 3 weeks. Even without the trailer, the same symptoms persist.

The engine is completely stock. I've tried a number of things with the 3.6 and using JScan to manually turn the rad fan on high during hill climbs helped slightly. Otherwise, everything else I've tried made no noticeable difference.

Replaced thermostat 3 times.
Replaced water pump
Oil cooler
Radiator twice, including testing the Mishimoto radiator.
Removed my winch to see if air blockage could be the problem
I even created stiffer radiator shrouds to force wind through the radiator, making sure it's not escaping around the radiator.

After my last trip through NV, ID, UT, CO, and the 17 hour drive home.. I picked up the Eco Diesel the day after I arrived home.

I already have the S&B hood scoops sitting in my office, along with a number of other mods. I think it will serve my use better, and maybe with a tune, have plenty of torque to pull mountain passes with comfort.

Was asking if the jeep was stock, not the engine. Yes, manual shifting is a thing and not unreasonable.
Bigger tires matter a lot.
Turning on ac can run the fans. Jscan only kicks them into test mode for a short time. I do that with the snow plow on to help the hvac

 

[Zachanadandy]

Yep and it's been over Donner many times before and after that incident. 6800 RPM is too close to redline to spend much time there.

I definitely wouldn't want to spend time at 6800 rpm. Isn't that at the redline? My point was nobody should be afraid of 6k to 6200 rpm on a regular basis running through the gears. That's where it makes peak power. Running it up to 6800 and holding it there long term is a recipe for disaster. As far as the EcoDiesel the only solve I've seen work reliably over on the JL forum is an auxiliary engine oil cooler. I'd imagine that would work well for the 3.6L too as the oil temp is usually higher than the coolant and hangs in the 230⁰+ range climbing mountains. I still find it weird that you had heat issues going slow. Never had that in either of our JLURs or my JT.

 

[ericw.]

Was asking if the jeep was stock, not the engine. Yes, manual shifting is a thing and not unreasonable.
Bigger tires matter a lot.

It's a jeep.. Nobody owns a stock jeep if they actually go offroad. lol

It has 35" tires, E Lockers front and rear, 4.56 gears, axle truss, c gussets, Metal Cloak 3.5" lift, bumpers, sliders, skid plates, the usual things for running moderate - difficult trails.

The trailer I pull is 2360 lbs when FULLY loaded for 3 weeks and I move it around in my garage by hand. Tongue weight couldn't be more than 40 or 50 lbs. It's very well balanced on the axle.

I don't usually take that much stuff though, so that's the max weight of the trailer for long trips.

...
Turning on ac can run the fans. Jscan only kicks them into test mode for a short time. I do that with the snow plow on to help the hvac

Yeah I set JScan to only run the fan on high for 5 minutes.

 

[ericw.]

I definitely wouldn't want to spend time at 6800 rpm. Isn't that at the redline? My point was nobody should be afraid of 6k to 6200 rpm on a regular basis running through the gears. That's where it makes peak power. Running it up to 6800 and holding it there long term is a recipe for disaster. As far as the EcoDiesel the only solve I've seen work reliably over on the JL forum is an auxiliary engine oil cooler. I'd imagine that would work well for the 3.6L too as the oil temp is usually higher than the coolant and hangs in the 230⁰+ range climbing mountains. I still find it weird that you had heat issues going slow. Never had that in either of our JLURs or my JT.

Yeah I remember my first trip to Ouray with the wrangler and while towing the same trailer, I had to pull over to let it cool down on the million dollar highway. Just slowing down wasn't enough.

Had to do that a few times on that trip, between Ouray and Aspen on some mountain roads also.

 

[Zachanadandy]

Yeah I remember my first trip to Ouray with the wrangler and while towing the same trailer, I had to pull over to let it cool down on the million dollar highway. Just slowing down wasn't enough.

Had to do that a few times on that trip, between Ouray and Aspen on some mountain roads also.

That's an 8200 pound trailer and had 0 heat issues even climbing 4k feet in 20 miles at 65mph. Fortunately the starting elevation was 300 feet so it wasn't down 30% on power like it would be at 10k'. The ecodiesel will definitely shine there thanks to the turbo, but there have been many diesel owners facing heat issues in the JL and JT. Since you've already fought (and lost catastrophically) heat issues I'd suggest an oil cooler before pushing it.

 

[ericw.]

That's an 8200 pound trailer and had 0 heat issues even climbing 4k feet in 20 miles at 65mph. Fortunately the starting elevation was 300 feet so it wasn't down 30% on power like it would be at 10k'. The ecodiesel will definitely shine there thanks to the turbo, but there have been many diesel owners facing heat issues in the JL and JT. Since you've already fought (and lost catastrophically) heat issues I'd suggest an oil cooler before pushing it.

Any specific brand of oil cooler that you'd recommend to kick start my research?

I'll get one on the way so it's ready to install. Appreciate the suggestion.

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