JK 3.6L 10,000 Mile Oil changes - Blackstone lab report
 

I have a 2013 Jeep Wrangler Unlimited Rubicon auto 5 speed with the Pentastar 3.6L engine. I am the original owner, and it currently has 86,000 miles on it. As per the manual, there is no set oil change increment per say, it just states to change the oil "whenever the oil change indicator light comes on". The manual also adds as a precaution that regardless of what the oil indicator light states, to never exceed 10k miles without getting the oil changed. The oil indicator light is supposed to reflect a multitude of calculations done by the vehicle's computer on how you've been driving since the light was last reset, plus temperature conditions, etc to "calculate" when you should change it. It does not just simply go off of mileage.

Now, I do a lot of driving (~35k miles a year) 90% of it being highway. My oil change light would always come on around the 9,500 mile mark, and I would get my oil changes around the 10k mark. I have been getting the oil changed at 10k miles right along, aside from my first oil changed which I had done at 6k miles. Even though my oil light indicator isn't tripping till around 10k, I have heard some reservation from the service department about letting the oil go for that long before getting it changed. Just as peace of mind for myself, and in case Chrysler ever gave me any hassle over a warranty repair because of it, I wanted to obtain scientific proof that the 10k miles oil changes I was doing was or wasn't ok for my jeep.

As a result, I obtained a sample of oil from my last oil change a week ago. My jeep had just hit 86k miles and I had 10k miles on my oil yet again. The oil was Penzzoil 5w/20 standard synthetic blend. Just got the report back today, and I must say I am pleasantly surprised!

I've attached the results below, but in a nutshell what they said is that 10k miles was not only perfectly fine, but a "piece of cake" for my jeep. That even at 10k miles my engine was showing less wear than the average oil change sample that they get at roughly 7k miles. In fact, they recommended I could go 12k miles based on the wear in my sample. The average has 21 elements of iron PPM and I only had 13. Viscosity was fine also and right in line. I spoke with a gentleman on the phone about it and he said that the Pentastars are really impressive engines and are top of the line. They've seen a lot of good things with them. He also praised Penzzoil (the oil I was using) and said that was a very high quality oil that is often over rated and under looked. The Molybdenum detected, which my oil had high levels in, are the teflon type additives that they use in it.

This is great news and really helped to put my mind at ease.

So those of you with the Pentastar engines, rest easy! Your jeeps can go a lot longer before oil changes than you think they can!

Below I've included a picture of my full report.


https://lh3.googleusercontent.com/FZ...s=w689-h603-no

My dealer wants me to come in every 5000km (~3000miles). Putting the business case aside for them, this is just terrible for the environment for all the folks that actually stick to that schedule...

Last time I changed the oil at 8k, it looked pretty much new coming out.

Yeah, 3k miles is way too low and just a waste of money. I would change it every 5k miles min, and you could even go a lot longer unless you were really doing some harsh driving. You can use my results as evidence!

What I've noticed is after 6000 miles the mpg will start dropping. I try to stick between 5-6k

Do you use synthetic? If so, I can't seeing changing oil after 5k....

The oil change interval really depends on the type of oil your using, standard, synth blend or full synth. I would change as follows.
Regular motor oil every 3000 miles, I wouldn't go much past 3k on regular conventional motor oil as it breaks down.
Synth blend every 5000 miles
Full synth 9-10000 miles
I run full synth in all our vehicles and change it around 8-10000 miles depending on the vehicle
My Ford Escape, every 10k. It just hit 170k on the escape and runs like a top.
Camaro I only change yearly cause I don't drive it much, usually less than 3k miles a year.
I'm in between jeeps for now until I find the one I want or order a 2016 but the jeep I plan to change oil every 8k or so.

Do you have the 3.8L minivan engine or the 3.6L Pentastar? When I had a 3.8 in my JK, I would change the oil around 6k too.



Can you even find non synthetic blend oil anymore? Most of the oil out there, even at $20 oil change shops, is synthetic blend. Synthetic blend is enough to get 10k out of an oil change with the 3.6 pentastar. Maybe if you're doing a lot of city driving or offroading, you might want to change it a little sooner.

Great info. :thumbsup: Ive been changing my oil once a year. I only drive about 6.5k miles per year. I find the once a year mark seems good for me, as Im actually at about 14 months and the oil change light just came on last week, for the first time ever. It does not stay on past the first minute of start up though. Ill get it changed this week. I might be 7.5k miles in to this run. I am using synthetics.

I change my own oil as the the oil change shops around my area are not to be trusted. Had one too many bad experiences.
last time I was at an oil change shop they broke the ram air box on my Camaro, they would not pay for a replacement and that was the last time I had my oil changed by someone else.
I do my own oil changes as well as all the mechanical work on all our cars.
I can do it, so I do.
To answer your question of can you find non synth oil? yes you can and a lot of oil change places still use it. The $20 oil changes in my area are all non synth.
A full synth oil change in my area is in the $40-50 range.
I know some local dealers charge their customers in the $35 range for synth blends.
Not sure what part of the county your in but that's been my experience in my area.

On my new cars, I do the first change at 3k, then at 6k, again at 10k, and every 5k thereafter, all synthetic. Super easy to remember when it's due, it keeps my suspicions in check even though it's probably done earlier than needed. My Jeep, my money, don't like it, call the EPA :)