Maximize 3.6 Reliability

[dstevens]

3.6 does not need walnut shell blasting. As far as I know walnut shell cleaning was only a thing for the early direct injection engines (BMW I believe). Port injection engines don't need it. Modern direct injection engines don't need it because they have better port shapes and internal EGR control so carbon build up is not a thing.

For the 3.6 the weak points are the lifters and followers. Then the usual water pump / thermostat business but the oil/water heat exchanger are known to fail.

Changing oil more often than necessary is throwing money away. If you really want then get it analyzed and look at the TBN and TAN. For my 3.6 things were good out to 7500 miles, but I only do long trips, which tend to be better for the oil, and the climate here is mild.

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[axhoaxho]

I had the 3.6L Pentasar V-6 in my JKRU. All I did was to change oil and filter every six months. The engine had zero problem, and my JK still ran like new when I traded it in after almost six years.

They put the 3.6L Pentastar in almost every models they made ..... 200, Town & Country, ProMaster, 1500 pickup, Charger, Wrangler, etc. It is not super powerful per today's standard, but it really is tried-and-true.

 

[Old Dogger]

O.K., you asked about the 3.6 engine. Below is from one of the Engineers that Designed it:

Nice! As an former Pentastar design engineer I am slightly bias but the engine is really high quality. Few points from the development using tens of millions of dollars in analysis and testing regarding the oil and durability..... The lighter oil was chosen mostly for fuel economy BUT engineering is the science of compromise. You help one thing but hurt another. A thicker oil will reduce timing chain and tensioner wear because the center timing chain idler doesn't go fully hydrodynamic till about 1650rpm on 5w-20. So, a thicker oil will lower that number slightly and with general loads/speeds the engine spends a lot of time around 1500-1750 rpm with the 8 speed. So thicker oil is a win there. Additionally, the earlier engines had what was called the "McDonald's Arches" in the idler bearing which was intended in making a more uniform distribution but in actuality acted as a knife edge. This design was changed around 2014 to a smooth bearing. So overall timing chain issues will likely follow the 2011-2014 engine years more than 2014+. Where you lose.... The head is very complicated with a Type II valve train. Meaning lots of things to pressurize and pump up at start up. A thicker oil didn't do so well here (on long sit times +cold start) and contributed to a overall increased engine wear especially in the head and cam bearings. Last point. This engine needs occasional WOT runs if you want it to last. Granny cycling is bad for it. So bad for it we actually created a new granny cycle test during the cylinder #3 misfire issue. The highest wear is in the valve guides, because of tight valve stem seals (for emissions, reduce oil burn). They basically dry out. When you go WOT/high rpm/load you get some fresh oil in there and this keeps the wear down. Thicker oil might not help this condition but we also change the valves/guides/seals in 2014+. Not sure the impact. Cheers! Kevin PS. Turn off stop start and do not run e85 if you are concerned about engine wear. Eats the engine alive.

 

[pablo_max3045]

Is it normal for dealership service depts to screw over the sales employees?

well, it's a dealer.... so it's not like they can help it. It's like the old carrying the scorpion across the river fable. It's just their nature.

 

[azjl#3]

Change oil every 4000 miles with synthetic name brand. Don't ever believe in the 15,000 mile between oil change. But, filters, have you ever heard of one clogging? Me neither, I've been doing this for 60 years. Right now JLUR is under warranty, dealer gets every maintenance. Once that runs out next year, I may slip filter changes to 8000 miles.

Use good gas, and I once a month throw in injector cleaner, lucas and mobil 1 techron. I trade between Chevron/76 gas and Circle K.... I notice a difference after injector cleaning, sometimes. I fell for dealer injector cleaning on first pentastar in 2012, it did have more pep, but also had a worse idle after they did it.

I started adding a half bottle of lucas friction modifier, it helps low viscosity engines keep oil on sensitive parts. It totally stopped a start up tick/knock in my hemi.

 

[Creeker]

Agree with those that say regular oil changes (3-5k miles), quality parts (filters, oil, etc.).
IMHO, an oil catch can is a great idea. Have catch cans on both JLR's The cans really catch a bunch of oil and prevent the oil from the crankcase ventilation system from getting into the intake system. How much benefit, who knows... but a cleaner intake system has to be better than one with an oil residue.

 

[conFUcius]

I’m still researching “keep the lubrication going all the time.” Also kinky. ?

But do you use 5 or 6 quarts?

 

[MichaelT333]

Wow, you are one of the first people I've read on here that thinks the same as me on oil and fuel. Top Tier fuel is the best thing for long life of an engine. Even if it isn't a DI engine.

I’m sorry but you guys are absolutely wrong in using the high octane gas. That engine was built for 87 octane. Not only does it run worse on high octane but it can hurt the engine. Highly recommend you do some research about it. Your wasting so much money on a myth.

 

[jellis4148]

I’m sorry but you guys are absolutely wrong in using the high octane gas. That engine was built for 87 octane. Not only does it run worse on high octane but it can hurt the engine. Highly recommend you do some research about it. Your wasting so much money on a myth.

We never said a word about high octane. Top Tier fuel has more cleaners and detergents in them to help DI engines from getting carbon build up on the valves. A lot of manufactures actually recommend top tier fuel. The less ethanol you put in an engine the better off it is.

 

[PBosch]

I always change the oil 2X as often as the manufacturer's recommendation. Cheap engine insurance.

I've always changed oil every 10K (usually synthetic, but not always). I've never owned a vehicle I didn't put 200,000 miles on, and I've never had an issue. IMO oil change frequency has heavily been, and still is, over rated as a means to generate cash flow for the service industry. The old 3K rule was BS. And when that was the rule, some people wanted to be "extra safe" and do it every 2K. Reading a good oil analsys test "should" give people some peace of mind.

 

[PBosch]

I’m sorry but you guys are absolutely wrong in using the high octane gas. That engine was built for 87 octane. Not only does it run worse on high octane but it can hurt the engine. Highly recommend you do some research about it. Your wasting so much money on a myth.

"Top tier" fuel. You may want to research that one also, unless you hate money.

 

[Fat_Tony_Ova_Hea]

Hey all,
I know this is kinda a ridiculous question to ask on a CJDR product based on their track records. I got the all gas 3.6 v6 because it was the most tried and true engine for the Jeep that has proved itself for years with some high mileage examples.

Of course I know they all have their potential of systemic failures and quality control issues. That being said, do any of the 3.6 masters & Gurus have any recommendations on mods or routine service outside 5k oil changes and good oil/air filters to help extend the life and reliability of this engine? I want to run this engine for as long as possible before it eventually pops and I get to swap a v8 in ?

 

[Willys41]

Baxter oil filter adapter with Purolator One filter. Eliminates dry and rattling valve train on start up
UPR Billet oil catch can. removes 99.9% of oil mist from intake are stream. You will be surprised how much oil it removes from the intake air
5/30 Valvoline oil
Stop /start eliminator
I watched a vidio few years ago about a guy that had a 3.6 in his delivery van
At 626K the motor failed and he put a new motor in
He took apart the old motor and to his supersize the bearing and cylinder walls looked almost new
What had failed was the timing chain and guides
https://macsmotorcitygarage.com/video-inside-a-chrysler-pentastar-v6-with-626000-miles/

The only thing I have concerns about is the rockers and lifters and keep listing for that tick tick tick put so fare all is good

 

[Tncdrew]

O.K., you asked about the 3.6 engine. Below is from one of the Engineers that Designed it:

Nice! As an former Pentastar design engineer I am slightly bias but the engine is really high quality. Few points from the development using tens of millions of dollars in analysis and testing regarding the oil and durability..... The lighter oil was chosen mostly for fuel economy BUT engineering is the science of compromise. You help one thing but hurt another. A thicker oil will reduce timing chain and tensioner wear because the center timing chain idler doesn't go fully hydrodynamic till about 1650rpm on 5w-20. So, a thicker oil will lower that number slightly and with general loads/speeds the engine spends a lot of time around 1500-1750 rpm with the 8 speed. So thicker oil is a win there. Additionally, the earlier engines had what was called the "McDonald's Arches" in the idler bearing which was intended in making a more uniform distribution but in actuality acted as a knife edge. This design was changed around 2014 to a smooth bearing. So overall timing chain issues will likely follow the 2011-2014 engine years more than 2014+. Where you lose.... The head is very complicated with a Type II valve train. Meaning lots of things to pressurize and pump up at start up. A thicker oil didn't do so well here (on long sit times +cold start) and contributed to a overall increased engine wear especially in the head and cam bearings. Last point. This engine needs occasional WOT runs if you want it to last. Granny cycling is bad for it. So bad for it we actually created a new granny cycle test during the cylinder #3 misfire issue. The highest wear is in the valve guides, because of tight valve stem seals (for emissions, reduce oil burn). They basically dry out. When you go WOT/high rpm/load you get some fresh oil in there and this keeps the wear down. Thicker oil might not help this condition but we also change the valves/guides/seals in 2014+. Not sure the impact. Cheers! Kevin PS. Turn off stop start and do not run e85 if you are concerned about engine wear. Eats the engine alive.

Thanks for posting this! ?

 

[donmontalvo]

O.K., you asked about the 3.6 engine. Below is from one of the Engineers that Designed it:

Nice! As an former Pentastar design engineer I am slightly bias but the engine is really high quality. Few points from the development using tens of millions of dollars in analysis and testing regarding the oil and durability..... The lighter oil was chosen mostly for fuel economy BUT engineering is the science of compromise. You help one thing but hurt another. A thicker oil will reduce timing chain and tensioner wear because the center timing chain idler doesn't go fully hydrodynamic till about 1650rpm on 5w-20. So, a thicker oil will lower that number slightly and with general loads/speeds the engine spends a lot of time around 1500-1750 rpm with the 8 speed. So thicker oil is a win there. Additionally, the earlier engines had what was called the "McDonald's Arches" in the idler bearing which was intended in making a more uniform distribution but in actuality acted as a knife edge. This design was changed around 2014 to a smooth bearing. So overall timing chain issues will likely follow the 2011-2014 engine years more than 2014+. Where you lose.... The head is very complicated with a Type II valve train. Meaning lots of things to pressurize and pump up at start up. A thicker oil didn't do so well here (on long sit times +cold start) and contributed to a overall increased engine wear especially in the head and cam bearings. Last point. This engine needs occasional WOT runs if you want it to last. Granny cycling is bad for it. So bad for it we actually created a new granny cycle test during the cylinder #3 misfire issue. The highest wear is in the valve guides, because of tight valve stem seals (for emissions, reduce oil burn). They basically dry out. When you go WOT/high rpm/load you get some fresh oil in there and this keeps the wear down. Thicker oil might not help this condition but we also change the valves/guides/seals in 2014+. Not sure the impact. Cheers! Kevin PS. Turn off stop start and do not run e85 if you are concerned about engine wear. Eats the engine alive.

What an incredible post!!!

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