How Many Miles Can You Put on a 3.6 Pentastar

How many miles can you put on a 3.6 Pentastar engine
3.6 Pentastar maximum miles

So you’re wondering how many miles you can safely rack up on the 3.6 Pentastar engine without any major issues. Or, you could be in the market for a vehicle equipped with the Pentastar and would like to know what a safe amount of miles are for these engines, without compromising reliability. If that’s the case, then this article is for you.

These Pentastar engines are quite bullet-proof but like all engines, they have a few niggles too. Let us look at some real-world examples of high mileage Pentastar engines and what you could possibly expect to go wrong.

There are only 4 weak points on the 3.6 Pentastar engine caused by plastic components used on critical engine parts. These include the following:

  1. Thermostat housing
  2. Water pump housing
  3. Oil filter housing
  4. Radiator tanks

There were also cylinder head issues with certain batches of the 2012 models which were caused by the sand casting process that resulted in head failures. These heads were replaced under warranty up until 150 000 miles (240 000 km’s). There was a second release later that year which resolved the head problem. More about that later.

If you would like to know more about specific year models and the common issues experienced on each, please read on.

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3.6 Pentastar longevity

The 3.6 Pentastar engine has been in production since 2012. Initially, there were problems with the heads where the sand casting process caused premature failures. Many are of the belief that the ticking noise on the engine was a sign that your head was on its way. However, the ticking noise is not a defective cylinder head but rather the rollers on the rocker arms wearing out and causing excessive play which causes the ticking sound.

These head failures caused by the sand casting process were noted by the manufacturer who covered the expenses under warranty. Since late 2012 early 2013, the engines have been fairly bullet-proof with only a small percentage being affected by the sand casting production problem.  Now it is mainly coolant-related component issues that are cropping up regularly.

Later the manufactures added stop-start technology in the JL and a new and improved transmission. The basic engine, however, remained in production for the last few years.

So it is fair to say the 3.6 V6 Pentastar is a good reliable engine. It pulls strong with impressive acceleration. It is regarded as among the most reliable high volume production engines around.

These engines are so good they have been incorporated into the RAMS, Chargers, Wranglers, minivans, 200’s, 300’s, GC, Challenger and more. It is a great engine.

However, there are some issues relating to the cooling system. Many owners have had to have the radiator, water pump, and oil coolers replaced at least once. Any component that has coolant flowing through it appears to fail fairly regularly due to plastic components failing and cracking, causing leaks and engine damage. If you are purchasing a used one, ensure you get an extended warranty.

Let us look at what some Pentastar owners have reported regarding the reliability of these engines.

I have 130K on my 2012 Rubicon with the first yr in the wrangler 3.6 and I’m happy. I also have had a new water pump, but that’s the only major repair I’ve had done. I do have meshing in front of the radiator to protect it from impacts, not sure if that’s why mine has lasted or not. Overall no major issues as of yet ( knock on wood ). I just ordered a new 2018 3.6, I trust the engine, if the diesel had a manual tranny I’d be going with that, but oh well.

https://www.jlwranglerforums.com/

This owner seems to be quite happy with his purchase even though he also had a water pump failure.

This owner doesn’t seem too pleased though,

Yeah….my 2012 JKU is at 102k miles & has had the heater core replaced twice, the radiator once, water pump once, oil pump once, and the starter once. Additionally (while not engine-related), the rear driveshaft just had to be replaced, seat heaters replaced, HVAC seals replaced (that was a big job), and at one point the rear brakes were leaking fluid. Internally, though, the 3.6 has been fine.

And, yes, I got my 2018 JLUR with the 3.6 as well.

FWIW, I got the lifetime warranty for both vehicles at the time of purchase. Best decision ever, but then again, I’ve had 7 Jeeps since 1979 & have come to know that for someone like me, who holds on to them for many years & miles, the initial cost more than pays for itself down the line.

https://www.jlwranglerforums.com/

He suffered from all the usual Pentastar issues and then some.

Yet another happy customer who believes in his Pentastar, let us read what he says

My 2013 JKU has 115 K miles on it. I changed the starter at around 90 K. other than oil changes at every five k with fully synthetic, and all fluid changes before required ( my choice ) the engine runs like the day it pulled off the lot. It is daily driven pulls trailers and goes into chemical plants and refineries. Hunts deer, hogs and wheels on a very regular basis.

Our 2015 JKUR had a radiator change at 40 k, other than that it was flawless until it was T boned, flipped and buried. I got big faith in our 2018 JLUR to do well. Jeep on!

https://www.jlwranglerforums.com/

So there you go, seems like a mixture of mostly happy owners even though many experienced the coolant and head-related issues in the earlier models.

2018 3.6 Pentastar problems

On these models the coil packs can become faulty, however, these packs are relatively easy to replace. Many times it comes down to a faulty connector. If the same cylinder keeps failing and they have swapped the coil pack around it rules out the coil.

They seem like great engines. They get excellent fuel economy. They are easy on the oil. There are some with high mileage but the engine has only been out for a few years.

I’ve read about the oil filter bracket that develops leaks and is a complex process to replace.

Some dealers blame the leak on the customer for over-tightening the oil filter cap.

Let us read what some owners have reported regarding these year models?

I have a 2018 JLSU and had no problems, until the other day, 11,500 miles. Driving 70, 8th gr, the engine light started flashing and the motor shook with loss of power. Nowhere to stop, I backed off and the light quit flashing but stayed on, along with the auto/stoplight. I’m able to drive it but the power is way off and rough idle at times.

I called the dealer and was told a 2-week wait; really?

I checked everything I could, had the code read (P105C) and have to wait to get it into the shop. Discouraging.

https://www.jlwranglerforums.com/

This customer is less impressed with his vehicle.

I dropped off my JLRU and was told, it was a bad valve guide causing the intake valve to stick. Somehow, that doesn’t make sense. Now I wait. I thought those problems were over, but I guess not.

Discouraging at the least as I was hoping to keep it a long time. Not as dependable as advertised. Maybe a call to Jeep Cares is in order, as information from the dealer is limited!

Diagnosed as a bad rocker arm etc., #4 cylinder (left bank); I thought they had that solved. I guess they should purchase better products.

https://www.jlwranglerforums.com/

3.6 Pentastar problems

It was well-publicized that in 2012 there was a massive problem on the 2012 Pentastar heads. The internet was rife with complaints and customers discussing this problem. There were so many complaints that the FCA couldn’t supply heads fast enough to keep up with production and supply customers with replacement heads. Customers reveal most dealers where aware of the issue and apparently turned them away due to a lack of inventory.

After much research into this weird phenomenon, it turns out there were some misconceptions with the original diagnosis regarding the cause of the clogged heads on the 3.6 Pentastar engine.

It was originally thought that the sludge and granules that collected at the bottom of the overflow bottle were sand from the production of the head and sandblasting process. It turns out that it’s not sand but rather Mopar stop leak additive they stick in coolant at the factory. The reason behind this was that any potential leaks would be sealed up by it while within the warranty period.

Many have submitted their coolant to labs which showed a high amount of aluminum on the coolant even though it was 100% OAT. Possible sources are shavings from manufacture or from all the various aluminum parts that the coolant is exposed to.

3.6 Pentastar life expectancy (High mileage)

So we’ve established that the early model 2012 3.6 Pentastar had some head-related issue which caused premature clogging and failures. Early 2013 models where more resilient however still suffered from the plastic components failing and causing overheating and other cooling system problems.

Many owners of the newer models seem very happy racking up decent mileage on these engines.

Lately, these 3.6 Pentastar engines have been known to rack up over 200 miles without any major hassles. In fact before 150 000 miles should be relatively hassle-free miles provided you are keeping an eye on the cooling system, the plastic bits and carrying out the scheduled oil changes on time.

Below is some customer feedback with real-life mileage figures.

2012 with 29k miles
– heater core and radiator replacement due to sand
– intermittent 3rd and 4th gear rattle, changed transmission fluid with synchromesh, better but not gone – some creaks and rattles, but no other real issues

https://www.wranglerforum.com/

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My 2012 JK has 50,000 miles, yep no typo here. Engine runs smooth and strong no issues. I will say the recalls were handled by the previous owner prior to my purchase. I can only say that I am confident this engine has many miles left in its journey. Take care of your jeep and it will take care of you.

https://www.wranglerforum.com/

————————————

50K 2012 JK, build date of 11/2011.
– Head issue at about 20K (warrantied)
– Transmission Cooler tube (warrantied)
– Passenger front ball joints at 50K (out of warranty)
– 
synthetic oil changes every 5K

https://www.wranglerforum.com/

————————————

Put 100,782 miles in my 2013 Unlimited Sahara, not one single issue at all. Just traded it for a new Rubicon. Had the Rubi for 2 weeks and have 2000 on it already.

https://www.wranglerforum.com/

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16700 miles on my 2012 jku. Build date 02/12. Just replaced the chirping water pump under warranty. No other problems.

https://www.wranglerforum.com/

Pentastar 3.6 timing chain replacement interval

The new 3.6L Pentastar Engine was first seen on the 2012 Jeep Wrangler. The 3.6L V6 produces 285 horsepower and 260 lb-ft of torque. Fuel economy for the 2-door model is advertised at 17mpg city and 21mpg highway.

The 3.6L Pentastar makes use of a timing chain in place of a timing belt. The timing drive uses four chains, each of which is a “silent chain link” design to improve sprocket engagement and cut noise, vibration, and harshness (NVH). These chains need to be replaced at some point. I would say a safe time to do this is around 90 000 miles – 120 000 miles.  Signs of a worn-out chain include loud rattling noises which means its probably time to start thinking of replacing the chains. Make sure you do this ASAP because of the way the engine is designed if the chain breaks its catastrophic engine damage.

Resources

Download Your FREE Wrangler D.I.Y Diagnosis & Trouble-shooting Guide Here

Conclusion

We’ve established that the early 2012 engines had a factory production flaw which was rectified later that year. We know the plastic bits causes issues with the cooling system when it fails. The rocker problem is well known and common on the Pentastar. A good aluminum aftermarket oil cooler would be a fantastic upgrade which will drastically improve reliability. The radiators will eventually leak, so keep your eye on it and replace it with a decent aftermarket one if possible.

Jade C.

4-Wheel drives and off-road driving techniques has been my passion for over 20 years. Here we strive to provide the most accurate, up-to-date, information about the functionality, common faults and latest technology built into most 4 Wheel Drives.

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