3.6 pentastar as bad as it seems ???

[Odyssey USA]

How much/rapidly would you say it's leaking? I assume it was coolant loss that made you investigate?

I noticed no coolant loss fora while as I just topped off carefully after a heater hose got a micro pin hole that would shoot a stream about a month before. I carefully keep an eye and have flushed this thing twice in a year (one due to 100k miles and the other due to the pin hole) and refill a few times OCD-like before I take it on the first drive waiting for the thermostat to open again but this time with some rpm, 3-4k, to push out possible air pockets.

All was fine for a month or so and then, still keeping an eye on coolant, etc, I noticed slight coolant loss and a rough cold idle. This was only two work days of mornings. By the third day I smelled it from the exhaust starting it in the garage. It could’ve been leaking before, but it was very minor, but it only made itself apparent over the course of three days.

With the scope, I’d guess there was at least a couple of tablespoons of antifreeze sitting there.

 

[LouC]

I don't disagree but my buddy has a '98 XJ on 37s with 5.13. He actually stroked the motor to .... 4.2?

My JL is running the same size rubber with factory 4.10 and on highway grades around Moab I can simply walk away from him. It's not even close.

Now, I'm sure he's heavier but honestly, it would hardly matter.

Anyway, the 4.0 is unquestionably durable but the Pentastar has better driveability we've come to expect from modern motors.

I have to agree, it has a lot more power, but keep in mind, when the 4.0 was produced, the transmissions used and gear ratios chosen were really not the best.
I'd like to see what one would feel like with a Chrysler 545 RFE (much more responsive than the old 42RE) and 4.10:1 gears instead of the 3.55:1 gears my 98 Grand Cherokee came with.
I agree with your point, but I also much prefer all cast iron construction, closed deck design, simple OHV design.
Not: open deck, all alu construction and 4 chains for the cam and oil pump. Definitely not in the realm of DIYs like the 4.0s are.

 

[GMBoy]

In my opinion the 3.6 pentastar is a better overall engine then the 3.6DI GM motor. I have both in vehicles I own. The 3.6 in the Cadillac CTS is powerful but reliability has been disappointing. Timing chains, deposits on the valves, water pumps, coolant leaks and injectors just a few issues I have had. No big deal to me because I own my shop but to a regular person these repairs are several thousands of dollars. The pentastars I have: 2014 Jeep GC Overand now at 201k and running great.No issues except the leaking oil filter adapter they all seem to have. No other issues and does not burn any oil. The other pentastar is in my 2020 Gladiator Rubicon. No issues at all at 78k miles currently. I think the pentastar has excellent smoothness, no worries of valve deposits and better MPG then the GM 3.6...which also gets less MPG's.

Just my personal experience.

As far as shop experiences...only see leaking oil filter coolers. Nothing stands out as bad that I have seen.

 

[Number_35]

In my opinion the 3.6 pentastar is a better overall engine then the 3.6DI GM motor. I have both in vehicles I own. The 3.6 in the Cadillac CTS is powerful but reliability has been disappointing. Timing chains, deposits on the valves, water pumps, coolant leaks and injectors just a few issues I have had. No big deal to me because I own my shop but to a regular person these repairs are several thousands of dollars. The pentastars I have: 2014 Jeep GC Overand now at 201k and running great.No issues except the leaking oil filter adapter they all seem to have. No other issues and does not burn any oil. The other pentastar is in my 2020 Gladiator Rubicon. No issues at all at 78k miles currently. I think the pentastar has excellent smoothness, no worries of valve deposits and better MPG then the GM 3.6...which also gets less MPG's.

Just my personal experience.

As far as shop experiences...only see leaking oil filter coolers. Nothing stands out as bad that I have seen.

Have you seen a drop in reliability with the Pentium Upgrade (PUG) engines? They have a reputation for blowing the HG on one bank.

 

[RBT]

Pondering about getting a jeep wrangler . New. 2 door Sport. Power nothing. Plain Jane. But dam there’s a lot of bad reviews on these engines. Are they as bad as advertised ???!I

The 3.6 and the 8hp is a well-proven powertrain. People love to spout nonsense on the internet.

 

[OVERKILL]

I have to agree, it has a lot more power, but keep in mind, when the 4.0 was produced, the transmissions used and gear ratios chosen were really not the best.
I'd like to see what one would feel like with a Chrysler 545 RFE (much more responsive than the old 42RE) and 4.10:1 gears instead of the 3.55:1 gears my 98 Grand Cherokee came with.
I agree with your point, but I also much prefer all cast iron construction, closed deck design, simple OHV design.
Not: open deck, all alu construction and 4 chains for the cam and oil pump. Definitely not in the realm of DIYs like the 4.0s are.

They do/did make a 392 Wrangler

 

[HemiBenny]

They do/did make a 392 Wrangler

I love it!

But if there’s any serious off-road shenanigans, an Atlas T-Case will need to be in the budget to deal with a 6.4l

 

[Skippy722]

I have to agree, it has a lot more power, but keep in mind, when the 4.0 was produced, the transmissions used and gear ratios chosen were really not the best.
I'd like to see what one would feel like with a Chrysler 545 RFE (much more responsive than the old 42RE) and 4.10:1 gears instead of the 3.55:1 gears my 98 Grand Cherokee came with.
I agree with your point, but I also much prefer all cast iron construction, closed deck design, simple OHV design.
Not: open deck, all alu construction and 4 chains for the cam and oil pump. Definitely not in the realm of DIYs like the 4.0s are.

The 545RFE/65RFE suck from a dynamics standpoint. 1st gear would be more lively given it is 3.00:1, but it will promptly fall on its face with its 1.67:1 2nd gear. But hey, its got a 1.50:1 kickdown gear between 2nd and 3rd

Now the NAG1 aka W5A580 on the other hand.... I really like that transmission.

 

[Kernel Potter]

We have one in my son’s ‘17 Wrangler. 96,000 miles runs great does not use any oil at all. Only repair has been the oil filter housing. I would buy another Jeep with this engine without hesitation.

There's a '17 3.6 in my family too but in a Pacifica. Otherwise the same exact thing; one repair to the oil filer/cooler housing.

 

[PontiacHO]

Had a fleet of Chargers for law enforcement with the 3.6. No more problems than any other make-model. Saw a lot of daily abuse and excessive idling.

 

[LouC]

There's a '17 3.6 in my family too but in a Pacifica. Otherwise the same exact thing; one repair to the oil filer/cooler housing.

That '17 Jeep is now at 145,000 miles still running well, got a set of new spark plugs and thermostat done recently. Last oil analysis was very good.

 

[D60]

They talked about this in one of the recent Tundra problem vids: I'm not sure when 145k became a good benchmark? Any modern vehicle should hit 145k miles with nothing but oil changes and tires.

 

[JimPghPA]

My sister and her husband have a 2025 Jeep Cherokee with the 3.6 and they traded in a previous Cherokee with a 3.6. No problems with either re the engine

Now days when buying new, look to see if the engine and trany have been in production for several years and also if any recent years of them have reoccurring problemd.

The 3.6 had problems in the distant past. But as far as I know, its recent history is good. Can't say that about many of the other brands 6 and 8 cylinder engines.

 

[Donald]

Pentastars are excellent engines. Like all engines there are known issues, such as camshafts, and early cylinder head issues. There are several high mileage examples driving all around you every day.

I wouldn’t touch a jeep myself except for the regular Cherokee 4.0

And the Jeep 4.0 had cylinder head cracking (#331 heads) and chunks of the piston skirt would break off and possibly trash the engine. Ask me how I know?

But people love their Jeeps.

 

[svtrit]

They talked about this in one of the recent Tundra problem vids: I'm not sure when 145k became a good benchmark? Any modern vehicle should hit 145k miles with nothing but oil changes and tires.

Getting a Chrysler product past 140k can be a challenge.

It’s not always the engine that is the problem.

 

[KrisZ]

As a Chrysler product owner I thank my lucky stars each day it starts. The feeling of anxiety, the anticipation when you insert they key, and the final feeling of relief when it does start is simply exhilarating. That’s when you truly feel alive.

 

[jadmt]

I have had 4 JK wranglers with 3.6's and never had any issues except on my 2014 had to have the oil filter cooler housing replaced under warranty at 50,000 miles..in 2024 I was buying a new JL wrangler and kind of wanted to try the 2.0 turbo but ultimately decided to stick with the 3.6. I will say I have had more issues with my 24 jlur than the previous ones put together...that being said no actual 3.6 problems but computer/ecm O2 sensor issues but those seem to have finally been figured out..

 

[IndyFan]

Getting a Chrysler product past 140k can be a challenge.

It’s not always the engine that is the problem.

I've had 4 go beyond 140k with no issues. 4 for 4. I've not had any wear out or retire. Longest so far was a 2008 Wrangler with 196k on it when I sold it. Ran like new. No rust, no issues. Lots of life left in it. It's on it's 3rd owner now and is at around 240,000 miles. I'm told it runs.....like new.

The current field is as follows....2018 Wrangler, 107k miles, 2021 Wrangler, 100k+, 2015 Renegade 120k, 2021 Compass, 112k, and 2021 Gladiator, 67k.

No engine or transmission issues of any kind in any of those.

 

[4wd]

As a Chrysler product owner I thank my lucky stars each day it starts. The feeling of anxiety, the anticipation when you insert they key, and the final feeling of relief when it does start is simply exhilarating. That’s when you truly feel alive.

 

[IndyFan]

I've had 4 go beyond 140k with no issues. 4 for 4. I've not had any wear out or retire. Longest so far was a 2008 Wrangler with 196k on it when I sold it. Ran like new. No rust, no issues. Lots of life left in it. It's on it's 3rd owner now and is at around 240,000 miles. I'm told it runs.....like new.

The current field is as follows....2018 Wrangler, 107k miles, 2021 Wrangler, 100k+, 2015 Renegade 120k, 2021 Compass, 112k, and 2021 Gladiator, 67k.

No engine or transmission issues of any kind in any of those.

I forgot one....A gear position sensor in the 2018 went bad.