Spark plug change on 2017 jeep grand cherokee 3.6

Joined
Jan 2, 2020
Messages
225
Location
South Carolina
Hello everyone.

This week going to be changing spark plugs on my 2017 grand Cherokee 3.6 pentastar. I was also advised to change intake gaskets since it's almost 100k miles on it. Got myself 2 cans of carb cleaner so I can clean out throttle body and everything around it. Anything else I should be looking to check/change while I'm taking intake off?
 
Any oil smell from the engine bay? I'd look closely at your oil filter / cooler housing once you get the intake plenum removed. Other than that, they say it's a good plan to replace the intake gaskets.
 
Any oil smell from the engine bay? I'd look closely at your oil filter / cooler housing once you get the intake plenum removed. Other than that, they say it's a good plan to replace the intake gaskets.
No oil smells. I recently changed oil and crawled around to make sure there were no oil leaks. Definitely will add oil cooler to my list to inspect. Under the cover and under the engine all looked dry.
 
  • Like
Reactions: JTK
if you're pulling your upper intake you want to replace the gaskets. Good time to do the pcv valve, too, if it hasn't been done. I did my Pentastar around 75K, plugs, gaskets and pcv...oh, and my oil filter housing / cooler started leaking around 80K...
 
if you're pulling your upper intake you want to replace the gaskets. Good time to do the pcv valve, too, if it hasn't been done. I did my Pentastar around 75K, plugs, gaskets and pcv...oh, and my oil filter housing / cooler started leaking around 80K...
Thank you! Just ordered PCV valve. According to limited previous records I have it hasn't been replaced. I'll just replace it for peace of mind.
 
I didn't know these engines lasted long enough to require spark plugs changes...

Just kidding, sorta.

I would also consider doing the oil cooler while you're there.
Just replace it even if there are no leaks? I'm not very familiar with those vehicles myself, and this jeep is new to me. Why would I need to replace it? Known problem?
 
i would definitely do the oil cooler and filter housing while you're in there, it's a common problem (atleast on the older pentastar) and 80% of the work is getting the intake off
 
Just replace it even if there are no leaks? I'm not very familiar with those vehicles myself, and this jeep is new to me. Why would I need to replace it? Known problem?


Also note the Dorman part does apparently/actually fit newer than he (or Dorman) claims.

It pains me to reco Dorman but the vid shows you the problem(s)
 
It's not a hard job. I did ours and used Autolite Iridium XP's and so far with 35k miles since the tune up all is running fine. Definitely replace the intake seals.
 
This on a 2017 mini-van. Best quote around ~1:29: "I kinda thought they'd fixed this problem with the newer versions of this engine, but apparently not..."

Note I own a '19 JL with the 3.6 so I'm not hating for fun, but I acknowledge stupid designs regardless of if I own them or not.

 
I wonder if everyone is on the same page, with suggestions of replacing the oil cooler "while you're there". Changing the plugs requires removal of the plenum (upper intake). Changing the oil cooler requires removal of the intake manifold (lower intake). You don't remove the lower intake just to change plugs.
 
I wonder if everyone is on the same page, with suggestions of replacing the oil cooler "while you're there". Changing the plugs requires removal of the plenum (upper intake). Changing the oil cooler requires removal of the intake manifold (lower intake). You don't remove the lower intake just to change plugs.
That's what I thought. I'm not a big fan of replacing just to replace, but it seems that if there are any inclinations I'll have to replace it.
 
This on a 2017 mini-van. Best quote around ~1:29: "I kinda thought they'd fixed this problem with the newer versions of this engine, but apparently not..."

Note I own a '19 JL with the 3.6 so I'm not hating for fun, but I acknowledge stupid designs regardless of if I own them or not.


It’s a stupid design, but I’m still 100% convinced that every one that has failed is due to over tightening. All you need to do is go till it stops, absolutely no more than that. I barely need a wrench to remove mine, no leaks at 90k. *knock on wood*
 
It’s a stupid design, but I’m still 100% convinced that every one that has failed is due to over tightening. All you need to do is go till it stops, absolutely no more than that. I barely need a wrench to remove mine, no leaks at 90k. *knock on wood*
In the vid I posted in #9 he describes various failure modes at ~2:04. At 3:56 he shows one from a '14 GC that lost one of the external blockoffs.

Overtightening the cap is the primary Cletus malfunction but there's plenty of other failure points that would be of no fault of the consumer.
 
Maybe you can zoom in and show me all the over tightened cooler issues in these pics but it’s usually the lower (circle) castings of plastic that leak

Small sample size
 

Attachments

  • AE05CE8F-784B-40EA-8801-6E4F7A188BCC.jpeg
    AE05CE8F-784B-40EA-8801-6E4F7A188BCC.jpeg
    154.7 KB · Views: 114
Just as a fun note RE: 3.6 oil coolers. As of a few weeks ago, the oil cooler/filter housings are no longer coming with either the temperature or pressure sensor due to "supply chain issues". At least that's the story I've gotten from both World Pac and the dealer...
 
I work on a fleet of a few hundred promasters with 3.6s. Every one is leaking, it’s to the point where I’m only replacing them when they’re leaking onto the ground (which means the valley has filled up with about 3” of oil, flowed down the back, down the bellhousing, filled up any cavities and places to pool on the transmission case and finally spilled over and drips to the ground).

if I worked in a real shop, every one would be getting written up to replace. Being a fleet shop, and I’m 1 of 2 guys willing to do the work, I just can’t keep up.

Ours are all 2018s with about 18-30k miles on them.
 
This passage is the oil pressure feed into the filter housing straight out of the block from the oil pump, and it's sealed by one tiny o-ring that's usually rock hard. We see plenty of them leak between the cooler and the housing too. For what it's worth I've changed a couple hundred of these stupid coolers and I have yet to run into one that's broken.
AE05CE8F-784B-40EA-8801-6E4F7A188BCC.jpeg
 
Just as a fun note RE: 3.6 oil coolers. As of a few weeks ago, the oil cooler/filter housings are no longer coming with either the temperature or pressure sensor due to "supply chain issues". At least that's the story I've gotten from both World Pac and the dealer...
I didn't think the OEM replacements ever came with the sensors, but I'm probably mixing it up with all the other supply chain issues..

Like @t1snwrbrdr12 said, these things can dribble for a long time before they get bad enough to fill the block valley and dribble over. That's why I mentioned above to poke around for a hot/burning oil smell under the hood.

Another tell-tale is is you rinse out the engine bay with water. You will see a huge rainbow sheen on the ground long before oil starts dripping to the ground.
 
Back
Top