Pentastar V6, 36K miles, intake valves/piston pics

[davison0976]

Hi Folks. While changing spark plugs on my 2013 Wrangler I snapped pictures of intake valves using a camera, and pictures of piston tops using boroscope. On Wrangler and probably all other models with Pentastar you need to remove intake manifold to change spark plugs, thus exposing the valves. Was pleased with the cleanliness of the intake valves, but hoped for pistons to be cleaner. Even thought it probably isn't that bad. Hope some of you will find this interesting.

I've owned the Jeep since it was brand new, with 9 miles on it. The service when the pics were taken was performed at 36,723 miles. Here is how it has been driven and maintained,

Driving: 80%city/20%highway
Oil: Top shelf synthetics. Mainly Castrol black bottle few years ago, lately Pennzoil Platinum.
OCI: Between 4000 and 5000 miles. I always change oil in the spring and fall regardless of mileage. Last change at 33,271 miles.
Gas: Predominantly Exxon. On occasion Shell and Valero. Exxon is simply conveniently located on my daily route.
Additives: Run Techron Complete Fuel System Cleaner 20oz a tank before each oil change, i.e. 2 times per year.

 

[dishdude]

Valves sure are clean. Pistons it is tough to tell what the camera is exaggerating, I have a feeling they would look a lot different to the naked eye.

 

[SR5]

Those valves are very clean. I don't know the Jeep Pentastar engine that well, it multipoint injected right?

 

[hpb]

Gee the spark plug replacement interval is short on those things - not even 60,000km. Looks clean inside though!

 

[GMBoy]

Originally Posted By: hpb
Gee the spark plug replacement interval is short on those things - not even 60,000km. Looks clean inside though!


I was thinking the same thing as my 2014 Jeep GC with the 3.6 says 100k mile plug change. I was planning to do them around 70k.

 

[The_Nuke]

valves look great, the pistons do not, but i dont think that means anything bad, just ugly piston tops, happens to the best of us

why doing the plugs so quickly? the OE pkugs will last every bit of 100K and then some...given how much work is required to change them, that 100K interval is just fine IMO

 

[SteveSRT8]

Can't imagine disassembling a healthy engine at that mileage. But those valves are sure clean.

SR5: it is a regular port injected engine, no DI yet.

 

[demarpaint]

Those valves look great, and I'd say the pistons look fine too. I thought the plug change interval was 100K miles on them.I have a 2016 Rubicon and was wonder how hard a plug change was going to be. It just looks time consuming.

How hard was the job, and how long did it take?

What scope did you use to get the piston top pics?

Thanks for posting!

 

[Oldmoparguy1]

Your valves are clean because the injector is spraying fuel directly on them. Notice the clean pattern on the port casting. E10 is keeping everything clean, no fuel additives are needed. I have a turbo 4 and and a 3.3 V6 that look the same, both with over 200k on them.

 

[ARB1977]

Looks great.

 

[Dyusik]

Whys so surprised @ port injected vehicle with under 40k miles. As spotless as it should be

 

[bullwinkle]

Valves are perfect, pistons need an Italian tune up!

 

[JTK]

Very cool to see the pics. Thanks for taking the time. We're at ~66K miles on the Pentastar on our 2013 Grand Caravan. It's been excellent. I don't plan on touching the plugs for another year or two. Did you find a lot of oil pooling in the upper intake? I'd hope it's not too bad at that mileage, but there's a lot of variables there..

 

[ejes]

Looks good. Port injection over DI was one of the big selling points for me when I bought my Pentastar equipped Jeep for this very reason. I've read D/C is developing DI for it though in future versions.

 

[davison0976]

Let me try to answer all the questions so far in one shot.


Originally Posted By: ejes
Looks good. Port injection over DI was one of the big selling points for me when I bought my Pentastar equipped Jeep for this very reason. I've read D/C is developing DI for it though in future versions.

Same here, multi-port injection Pentastar was one of the main selling points for me. It's still one of the fewer and fewer remaining engines out there not using direct injection. However, for 2016 revision they've added EGR, and now part of exhaust manifold gasses are being recirculated back into the intake. Although, I believe only Grand Cherokee is getting the updated version of this engine right now.



Originally Posted By: The_Nuke
why doing the plugs so quickly? the OE plugs will last every bit of 100K and then some...

Ture. Manual calls for 100K miles replacement. I wasn't going to replace the spark plugs. I only wanted to look inside one cylinder with the cheap borescope I had just gotten. Electrode on the plug I took out for this experiment looked unreasonably worn (see plug on the left in the pic below). I immediately linked that observation with a little rough idle I've been experiencing for sometime now. The rest was history. I replaced Champion RER8ZWYCB4 plugs with Denso SXU22HCR11S. So far engine is very smooth.





Originally Posted By: demarpaint
How hard was the job, and how long did it take? What scope did you use to get the piston top pics?

I used this borescope - Borescope Aoleca 2 In1 with Android phone (didn't try it on PC or Mac). I wanted to look at the side of the cylinder even more than the piston, but the stroke in this engine is so small, smaller than the bore, that there was no way for me to lower and turn borescope camera deep enough. Took me about 4 hours, but I never rush when I work on my vehicles to say the least. By the way, the intake manifold is plastic and torque spec is emboldened on it is 7-9Nm. I torqued to 156 in-lbs. The job itself isn't hard, just a little time consuming. Make sure you have a decent plastic clip removal tool. There is at least one good video on youtube. Actually, here it is Jeep JK Pentastar Spark Plug DIY.



Originally Posted By: bullwinkle
Valves are perfect, pistons need an Italian tune up!

I know, right? I commute 7 miles one way through a town. That's what probably sludges them up.



Originally Posted By: JTK
Did you find a lot of oil pooling in the upper intake? I'd hope it's not too bad at that mileage, but there's a lot of variables there..

Not much oil, but there was some. See pics below. Internal walls of the intake manifold are oily from the PCV vapors.

 

[davison0976]

CORRECTION on torque spec stated above.

Spark Plugs: 156 in-lbs
Intake Manifold Bolts: 71 in-lbs (mistakenly stated as 156 in-lbs in previous post)

 

[edyvw]

Wait, am I only one who read that you have to take out intake manifold to change plugs?

 

[dishdude]

Originally Posted By: edyvw
Wait, am I only one who read that you have to take out intake manifold to change plugs?


Not all that uncommon on modern V engines.

 

[meep]

^^^ and I was worried about the complexity of owning swedish cars...^

 

[KrisZ]

At least pentastar engines prior to 2016 don't have EGR gasses going through the intake manifold, as it's all done through valve timing. This way the intake manifold will just stay wet with oil instead of being covered with black goo that is a result of oil mixing with EGR gasses. But for 2016+ I read these engines have a regular EGR that goes through the intake manifold.

The black piston tops are a result of mostly city driving which is much richer than highway commutes which tend to be more steady state, much leaner mixture and hotter combustion chamber.