Latest TSB on the Pentastar engine

[GabeBoyTheGreat]

6MT Owners when reading this

Sure, let's fix a hardware issue with software, like they did with the clutch! It worked out so well!

Maybe updated software will prevent the cams from wearing

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[jeepingib]

There are quite a few documented cases of this happening, I don't understand why there are some who are so vehemently opposed to this being a fairly large issue. Does denying it get anyone anywhere?

 

[Beach Nut]

Is there a Class Action Lawsuit we can join? If not, WHY?

 

[Beach Nut]

Recalls are usually for safety issues.

So going down the highway and your engine losing power isn’t a safety issue?

 

[Jay Gatsby]

Is there a Class Action Lawsuit we can join? If not, WHY?

Start one

 

[yokramer]

There are quite a few documented cases of this happening, I don't understand why there are some who are so vehemently opposed to this being a fairly large issue. Does denying it get anyone anywhere?

Speak about it Nevermore

 

[GeorgeYJ2JL]

It could be more to this then is being said. I had a P0304 code with rough idle at 416 miles. Yes, 416 miles. It turns out, in my case, it was debris in the hed gasket that caused the seal to fail. I may have been lucky in that it failed earlier than later. Nevertheless, the car required a new head gasket and all the rest of the necessary rebuild. What a shame. Stellantis offered me 8 free oil chages over 4 years for my trouble. Well, the car still has a rough idle and I'm going in for the 4th time in the 5 weeks I've bought the car. Mind you, this is a new car.

 

[Ron Texas]

There are quite a few documented cases of this happening, I don't understand why there are some who are so vehemently opposed to this being a fairly large issue. Does denying it get anyone anywhere?

Quite a few is accurate. Without knowing what percentage of engines are experiencing the problem it's hard to say if the issue is uncommon or fairly large. Someone said a large dealer who sells well over 1,000 units per year did 10 repairs which might put the problem at below 1%. Nobody here really knows.

 

[Ron Texas]

2.4L Multi-airs had a near 100% defect rate. The concern came from how *much* oil was being burned. In a normal world the owner would've checked their oil once in awhile the issue would have never been noticed in any severity. Instead we had ~7500-10k oil change intervals and the engine was running low on oil around 5000 miles. Some would burn half a quart every 1000 miles and some nearly 1.5 quarts. Capacity of 5.5qrt, at 3qrts low it can exhibit stalls during forceful maneuvers. At 4 qrts low it'll stall just coming to a stop light. This is because it used oil pressure to actuate the intake valves in leu of a camshaft (hence the multi-air part). Without pressure the valves don't open and the engine stalls from lack of oxygen.

Stellantis released three separate fixes to appease the EPA depending on model year. They determined that continuing to inject fuel under coast downs to prevent some vacuum was sufficient enough. This had to be done without changing the MPG standards. Some vehicles only were authorized for the flash, while some got the flash and a consumption test, while others couldn't make the MPG standards with the update and were given complete engine replacements if they failed the consumption test. The newer engines had re-designed piston rings to help reduce oil burn.

They also made it rather annoying to perform the consumption test. The owner had to return between 1300-1500 miles for a follow up inspection. If you went over you had to start all over again. A large amount of owners simply weren't informed and had the recall checked off without ever coming back for the inspection. Even those that got the update done still frequently had excessive consumption. If they were under powertrain warranty we could get them replaced, but they're all well out by now.


The entire fiasco could've been avoided by simply lowering the OCI to 5000 miles. It took a lot of owner neglect to get to the point of stalling, but you can't blame them due to the long intervals I guess checking your oil isn't something people do anymore. It's like modern vehicle owners expect to never have to open their hoods once during ownership.

That sounds like a big mess.

 

[Ron Texas]

It's a bit elusive to nail down exactly how serious the cam wear problem is. For a dose of sanity go over to bronco6g and find the thread about open recalls on Bronco's with no parts available for the fix. After reading that you will realize things are not so bad in Stellantis land.

 

[jeepingib]

Quite a few is accurate. Without knowing what percentage of engines are experiencing the problem it's hard to say if the issue is uncommon or fairly large. Someone said a large dealer who sells well over 1,000 units per year did 10 repairs which might put the problem at below 1%. Nobody here really knows.

I get where you're coming from, the Pentastar has a solid reputation overall, and it's true that millions of these engines are out there doing just fine. But I think it's also fair to say that the 2018+ Gen III version in the Wrangler has shown some concerning patterns, especially once you're outside the warranty window. It may not be a "bad engine" in the grand scheme, but there are a couple of recurring issues worth keeping an eye on.

Head Gasket Concerns
There’s a growing number of post-warranty failures being reported, most commonly around 70k–120k miles. These aren’t isolated to heavily modified rigs either. A few things stand out:
The Gen III raised the compression ratio to 11.3:1, but Jeep still recommends 87 octane. That’s pushing the knock margin, especially in hot climates or when loaded.
The PCM does retard timing when knock is detected, but it can’t eliminate all pre-ignition. Over time, chronic knock can stress the head gasket seal, especially between cylinders.
While it’s not officially confirmed, several teardown techs have noted inconsistent torque on head bolts from the factory.
So is it a design flaw? Maybe not. But it’s a stack-up of compromises that are showing up more often than you’d expect in stock engines.

Cam Follower / Valvetrain Failures
This one's harder to dismiss. Jeep has issued multiple STAR cases and updated parts for cam followers and cams, which means they acknowledge something needed correcting.
And just to clarify, the 3.6L Gen III doesn't use traditional roller lifters. It uses a 3-lobe cam and a locking follower design:
The outer lobes operate the follower in low-lift mode with a roller.
Under high demand, the inner lobe engages, and the roller bearings disengage via a locking mechanism inside the follower.
The issue is that this locking mechanism can stick or fail, especially when oil is hot or thinned out. And the engine runs 0W-20 from the factory, which helps with CAFE targets but offers less protection under stress.
Failures are more common on the passenger-side bank, especially cylinder #1, which may point to oil flow dynamics, that’s the first in the oil path, and possibly the most starved if there’s aeration or varnish buildup.

These aren't catastrophic flaws for every owner, but they do represent weak points in this generation.
Running higher octane in hot climates, using a higher HTHS oil like 5W-30, and shortening oil change intervals are practical ways to reduce risk.
If you’re inside warranty, no problem. But if you're planning to keep the rig past 100k, proactive maintenance makes a difference.

Bottom line: not every engine fails. But there’s enough pattern here, especially from teardown reports and parts revisions, to call it more than just anecdotal. Doesn’t mean the sky is falling, but pretending there’s nothing to it isn’t helpful either.

 

[Ron Texas]

@jeepingib Thank you for your well meaning comments. There is a problem, but there is a lack of information as to the frequency. When you say not all engines fail, that leaves a lot open to interpretation. There is no verifiable information as to the frequency of repair. The best guess is .5% to 1%. That's not acceptable, but not a disaster either.

 

[jeepingib]

@jeepingib Thank you for your well meaning comments. There is a problem, but there is a lack of information as to the frequency. When you say not all engines fail, that leaves a lot open to interpretation. There is no verifiable information as to the frequency of repair. The best guess is .5% to 1%. That's not acceptable, but not a disaster either.

And that number you are using is pure speculation as well. The truth is it has happened enough that there were over 12,000 orders placed and on backorder for the passenger camshafts. That's a lot. Part of that is due to a new part coming out so there was a period of no availability while the stock was replenished, but that still speaks to it being more common than you are alluding to. The truth in numbers would only be ascertained by having the total number of cams sold, and we don't have that.

 

[flyer92]

It's like modern vehicle owners expect to never have to open their hoods once during ownership.

...or open the owner's manual, for that matter.

 

[Jtphoto]

And that number you are using is pure speculation as well. The truth is it has happened enough that there were over 12,000 orders placed and on backorder for the passenger camshafts. That's a lot. Part of that is due to a new part coming out so there was a period of no availability while the stock was replenished, but that still speaks to it being more common than you are alluding to. The truth in numbers would only be ascertained by having the total number of cams sold, and we don't have that.

0.5% of 10M is still 50,000 units. Still not a lot in the big picture. I know, we would like to see 0 failure BUT that’s not realistic for any manufacturer, in this case especially since there isn’t just one machine shop that’s dedicated to making all the 3.6L cams. In fact a search provided a vague number of different shops.
And again how many of that 0.5% were neglect or abuse.
Parts supply issues can be attributed to many things as well, like steel tariffs and material availability.. Plus, new car manufacturing will take priority over warranty parts supply.

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