A Jeep Tech, Mechanic, & JT owner answers reliability questions

[hoch]

That’s funny , the 3.6 can’t hold a candle to the reliability of the 3.8. The 3.8 in the Wrangler wasn’t the problem. The factory gearing was. There are an awful lot of high mile 3.8s still out there considering they only made them 5 years And the last run was already 12 years ago.

Do you have any stats to back up that claim? Or is this all anecdotal evidence?

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[Jtphoto]

Do you have any stats to back up that claim? Or is this all anecdotal evidence?

There are lots of stats out there if you choose to look for them. The 3.8 was first introduced in 1989. Lots of high milers out there to prove it.

 

[Coltron_Actual]

That’s the part that got me looking sideways and raising my eyebrow. That’s not possible. Even if given the benefit of doubt and say 2 year time frame (2018 model year acquired in 2017), that’s 527 miles per day, average. Not even professional truckers do that kind of mileage.

Which confirms, just like any other mechanic, take what this guy says with a grain of salt. It’s not gospel. In my mind, 3.8 sucks and 4.0 had its share of problems. I’d put the 3.6 up there with both of them.

Could it have been on a chassis dyno in a test stand? Not attempting to shill for this guy, just a thought that popped in my head.

 

[Coltron_Actual]

3.6L and 3.8L owners arguing over who is most reliable.

Leaky, smoky 4.0L owners off in the distance:

 

[hoch]

3.6L and 3.8L owners arguing over who is most reliable.

Leaky, smoky 4.0L owners off in the distance:

Ha ha. Touché.
But I will say, having had a 4.0 in the family (20 some odd years ago), I do not miss it at all. Sure, it was a good engine but it was so slow. Couldn’t hold 5th gear with any hint of a hill. Ours had some serious oil consumption issues at 150k.

It’s like the Toyota 22RE. Legendary engine. But we tend to forget all the downfalls. You couldn’t give me one today.

 

[aldo98229]

I had a 4.0 I-6 in both my Grand Cherokees: yes, it was slow, but it was strong and smooth.

I recall going up the long, steep inclines of Cajon and Tejon passes, outside Los Angeles: with a vehicle full of people and camping gear, I could maintain my speed all the way to the top without straining the engine. The speed limit is only 60 MPH there, but I’d be able to pass two-thirds of the other vehicles on the road straining uphill.

 

[Coltron_Actual]

Ha ha. Touché.
But I will say, having had a 4.0 in the family (20 some odd years ago), I do not miss it at all. Sure, it was a good engine but it was so slow. Couldn’t hold 5th gear with any hint of a hill. Ours had some serious oil consumption issues at 150k.

It’s like the Toyota 22RE. Legendary engine. But we tend to forget all the downfalls. You couldn’t give me one today.

I won't give you one, I'll keep it myself lol

You're not wrong, 190 hp, or 210 hp depending on year, is an acquired taste to live with on the daily when it's put in a vehicle that is shaped like a brick. I had a Subaru that only made 148 hp and it was exponentially more pleasant on freeways. We drove the JL from PA to FL for christmas and besides wind noise, I have no complaints. In a TJ it would have been absolute torture.

That being said, if I'm running errands, I don't have to go on freeways, and the weather is nice I'm almost always taking the LJ, and not the JL. It's just my favorite 4 wheel transportation in my garage.

 

[bcupton]

I especially liked what the FCA mechanic had to say about Cold Air Intakes (CAI). What a waste of money. I’m putting the factory air box back on.

 

[Quadjeeper]

I would agree with the 4.0 statement 100% I had a 99 and that engine was awesome

Still driving my '99 XJ with a 4.0. 277k on it. That is it lurking in the garage.

 

[jollyjerry]

Surprised the aux battery will discharge on it's own in 30 days. Even with a small capacity, would think there's minimal drain with the car off assuming everything works. I hit the auto start/stop disable whenever I drive b/c I dislike the restart, but I'm not worried about the aux battery now that they fixed it so it's no longer a no-start issue.

It'd be nice if there was room for 2 full size batteries in there. Sell the stock one with small aux battery for cost savings, then sell a full one as an upgrade or just have the space available for someone to add one

 

[JimsRubicon]

He said the steering stabilizer causes death wobble. Nope not the cause. I stopped watching right there.

Back around 1990 an old girlfriend had an Islander and I had the base model. She left the factory steering stabilizer on and eventually developed death wobble. She never went off-road. It went away when I replaced it with an aftermarket upgraded stabilizer. I had replaced mine with an upgraded aftermarket stabilizer and I never had the issue. So in my experience, the stabilizer does play a part in the death wobble problem.

 

[Heimkehr]

It seemed like it was a "yes, but...." and didnt get the time to fully answer. It would be good if he had the chance to clarify with what needs beefed up and whatnot.

Agreed. I watched the video against my better judgement, figuring the questioner would be as chatty and interrupt-y as his promise of a "conversation" suggested (and he was so).

There's an opportunity for someone to edit that video so that the mechanic, who is clearly experienced, does the majority of speaking. Better yet, superimpose the questions as text on the screen and remove Babbling Brad completely.

Surprised the aux battery will discharge on it's own in 30 days. Even with a small capacity, would think there's minimal drain with the car off assuming everything works.

It'd be nice if there was room for 2 full size batteries in there.

I thought the same thing, figuring that "30 day" estimate might be walked back to parasitic draws. If the aux batteries were that lame, I should experience the same thing with every motorcycle that I've owned...and I haven't.

As for having space for two full-size batteries, we already do. That's the precise solution that Genesis Off Road provides with their kits.

 

[jollyjerry]

Agreed. I watched the video against my better judgement, figuring the questioner would be as chatty and interrupt-y as his promise of a "conversation" suggested (and he was so).

There's an opportunity for someone to edit that video so that the mechanic, who is clearly experienced, does the majority of speaking. Better yet, superimpose the questions as text on the screen and remove Babbling Brad completely.



I thought the same thing, figuring that "30 day" estimate might be walked back to parasitic draws. If the aux batteries were that lame, I should experience the same thing with every motorcycle that I've owned...and I haven't.

As for having space for two full-size batteries, we already do. That's the precise solution that Genesis Off Road provides with their kits.

Genesis kit is exactly what I imagined. Their install video leaves the aux battery cables off. I'm surprised that doesn't trigger a warning light.

 

[Zandcwhite]

The 3.8L was reliable for the same reason most Toyotas are, so under powered and boring to drive that it lives an easy life. That thing couldn't get out of its own way even in a stock 2dr JK with a manual unless you downshifted 3 gears and revved it to the moon, which is not how most Jeep drivers drive. The 4.0L was not quick, but was a rocket by comparison. The only wrangler engine that was worse was the 2.5L.

 

[Dragon52]

I have a 2020 Rubi Diesel that has just over 35000 miles as of today. All has been good, other than a PCM total failure May 2022. Following the fix, no problems. But I have only seen the diesel particulate filter regen notice once at roughly 10,000 miles and none since. Should I be concerned or is it simply regenerating in the background without notice. My JL is a daily driver and I live in a rural area so most of my driving is 45 - 55 mph. I do about 12,000 miles per year total with 3000 - 4000 of those miles at highway speed 70mph+.

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