Factory/Dealer filled 6 quarts in my new 3.6

[ShadowsPapa]

I hate to be a negative nelly here... but I have had to replace my rear main seal on my 3.6 (2018) twice now. First was when I purchased the jeep used. Second time...

Chasing a bad cam shaft I used an engine flush before an engine oil change. The flush was approximately 1 quart of fluid. Ran it 10 minutes. Instantly I got a new leak on the rear main seal.

Pull the rubber plugs in the bottom of the transmission and watch it closely.

Oil flush can be BAAAD news as it almost always contains solvents. Guess what solvents do to rubber compounds.
I never recommend a "flush" without extreme care, or understanding the possible consequences of solvents and/or knocking crap loose that perhaps shouldn't be.

A couple of oil changes would have accomplished cleaning things out without solvents.

my 3.6 (2018)

2018 was a transition year for the Wrangler - JK or JL? It matters. The JL has the upgrade engine, the JK has Gen 1 - the pre-upgrade engine.

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[bllprk402]

Oil flush can be BAAAD news as it almost always contains solvents. Guess what solvents do to rubber compounds.
I never recommend a "flush" without extreme care, or understanding the possible consequences of solvents and/or knocking crap loose that perhaps shouldn't be.

A couple of oil changes would have accomplished cleaning things out without solvents.



2018 was a transition year for the Wrangler - JK or JL? It matters. The JL has the upgrade engine, the JK has Gen 1 - the pre-upgrade engine.

Its a JLU. With the VVT and VVL systems. Hopefully they updated the engine design (since my 1st year JLU), but this rear main failure was very common because the JK's used 6 quarts and dealers made mistakes when doing oil changes.

My engine is a POS. Phaser failures, cam and lifter failures. Actuator issues ect... trying to get it to run properly was the reason for the flush. The flush chemicals had zero time to destroy the seal. It was a high pressure situation that found a weak location to relieve itself.

Love it how people get instantly attacked on these sites. I just told him to keep an eye on the rear main seal... better to figure it out now and place blame on the oil change than wait and find it later...

 

[ShadowsPapa]

but this rear main failure was very common because the JK's used 6 quarts and dealers made mistakes when doing oil changes.

5 vs 6 quarts has nothing to do with rear main seals. Not a thing. That's internet lore, people trying to explain and looking for reasons.
think of a seal on a lawnmower engine -laying in a pool of oil its entire life, not leaking.
Seals like these are made to operate under at least 7 psi - and there's really no hard pressure on an engine oil seal. There's a gap between the rear main bearing and the rear seal where oil drains back into the sump. There's a slinger of sorts made onto the rear of the crankshaft to guide and sling oil away from the seal.
The crankcase operates under LOW pressure, even a vacuum! Not pressure.

If the oil was so deep as to bury the real main seal (and 6 quarts isn't) you'd be foaming up the oil to the point of engine failure - loss of oil pressure due to aeration, etc.

The flush chemicals had zero time to destroy the seal.

I'm going to leave that at "whatever"......

It was a high pressure situation that found a weak location to relieve itself.

Sorry, no pressure against the seal.
I know - I've built a ton of engines over the years. "Pressure against the seal" is an internet thing.

Love it how people get instantly attacked on these sites. I just told him to keep an eye on the rear main seal... better to figure it out now and place blame on the oil change than wait and find it later...

If he blames the oil change, he'll be proven to be very wrong. By people who actually know.

No one is attacking anyone! It's just a matter of correcting bad/wrong/incorrect information.
Over-filling to 6 quarts has NOTHING to do with rear main seals.
You likely made connections that aren't there, or read it somewhere - from someone who has never even been inside of an engine. The "internet experts" who haven't seen a crankshaft in their hands, but sure know about oil seals.

Not attacking, just correcting for BAD information.

Thousands of the upgrade engine in JL and JT have had 6 quarts - no ill-effect. Especially rear mains.

I'm a mechanic - those claiming such things the extra quart causing leaks are not.

I saw your post on the Wrangler side blaming that bit of extra on the seal leak. Funny thing - others in that thread and that side of the forums in general also pretty much poo-poo the rear main being a big issue.

 

[Charles 236]

For all the hate the 3.6 gets. It’s a stout POS. Sure it’s got headaches and failures. But even the cam failed ones still manage to start and move under their own power. For all the abuse mine has been, it has nothing but my respect at this point.

The Classic Pentastar was incredibly tough. I was given a repair order for one about six or seven years ago. Another tech had pulled the oil pan and the left valve cover (and upper intake manifold to get to the valve cover) to diagnose a noise, then pushed it out into the lot to wait for the new engine to arrive. When I got the RO, I had to take it around the lot and up a pretty steep slope to get to my bay. I jumped in and fired it up, and started around the lot. A couple of other techs ran after me trying to get me to stop. I drove around to the steep slope leading to my bay before I stopped. I got out, raised the hood and saw that there was no valve cover on the left, then the techs caught up to me and told me the oil pan was off the engine. I didn't care, I was replacing the engine anyway. But it needed all six cylinders to climb the slope into my bay, especially running without the upper intake manifold. I installed the three coils, fired the engine up and drove it into the bay. The two techs were afraid it would lock down running without oil, but it only needed to run about five minutes or so.

 

[Stan H]

I hate to be a negative nelly here... but I have had to replace my rear main seal on my 3.6 (2018) twice now. First was when I purchased the jeep used. Second time...

Chasing a bad cam shaft I used an engine flush before an engine oil change. The flush was approximately 1 quart of fluid. Ran it 10 minutes. Instantly I got a new leak on the rear main seal.

Pull the rubber plugs in the bottom of the transmission and watch it closely.

And that is EXACTLY % WHY I will not use an engine flush. Imagine what is is doing to the bearings et al as it breaks everything loose so it can go surging through the intricate electrical components like the phasers etc. No way in Heck would I ever do that.

 

[Stan H]

5 vs 6 quarts has nothing to do with rear main seals. Not a thing. That's internet lore, people trying to explain and looking for reasons.
think of a seal on a lawnmower engine -laying in a pool of oil its entire life, not leaking.
Seals like these are made to operate under at least 7 psi - and there's really no hard pressure on an engine oil seal. There's a gap between the rear main bearing and the rear seal where oil drains back into the sump. There's a slinger of sorts made onto the rear of the crankshaft to guide and sling oil away from the seal.
The crankcase operates under LOW pressure, even a vacuum! Not pressure.

If the oil was so deep as to bury the real main seal (and 6 quarts isn't) you'd be foaming up the oil to the point of engine failure - loss of oil pressure due to aeration, etc.




I'm going to leave that at "whatever"......



Sorry, no pressure against the seal.
I know - I've built a ton of engines over the years. "Pressure against the seal" is an internet thing.



If he blames the oil change, he'll be proven to be very wrong. By people who actually know.

No one is attacking anyone! It's just a matter of correcting bad/wrong/incorrect information.
Over-filling to 6 quarts has NOTHING to do with rear main seals.
You likely made connections that aren't there, or read it somewhere - from someone who has never even been inside of an engine. The "internet experts" who haven't seen a crankshaft in their hands, but sure know about oil seals.

Not attacking, just correcting for BAD information.

Thousands of the upgrade engine in JL and JT have had 6 quarts - no ill-effect. Especially rear mains.

I'm a mechanic - those claiming such things the extra quart causing leaks are not.

I saw your post on the Wrangler side blaming that bit of extra on the seal leak. Funny thing - others in that thread and that side of the forums in general also pretty much poo-poo the rear main being a big issue.

@ShadowsPapa is totally correct folks , the PCV takes any excess pressure and reroutes it back into the intake thats the whole purpose of it and 6 quarts aint gonna do squat cause at least 2 quarts is floating around in recesses filter oil cooler heads crank mains. Etc.. for only a span of 3.6 seconds does all the oil in a 3.6VVL remain in the pan after a cold start setting overnight or longer than 35minutes. Which is only gonna leave 2 or 3 quarts for the engine to draw from .
Now I aint a life long mechanic shadetree like a lot of us. But I have been working on engines since I was knees high to a grasshopper . I also stayed at a Holiday Inn express once.

 

[ShadowsPapa]

I also stayed at a Holiday Inn express once.

Hey, do you have any inside info from Jeep?

 

[MT1]

Yeah, 5 qts cold is exactly at the top of the fill range on the dipstick on mine.

I find the Jeep 3.6 dipstick to be notoriously inaccurate.

With exactly 5 quarts put back in, run, then shut off for a couple of hours, mine reads up over the molded part back onto the cable.

Good observation. Mine, 2023, 5 qts. is exactly at the full fill mark, which it should not be when cold. "Cold" in this instance meaning after an oil change, and adding a 5 qt. jug, then waiting fine minutes or longer.

So, is Stellantis increasing profits little by little, like a cm of cable at a time? Joking, but, maybe not...

 

[Old Dogger]

Unfortunately, I have heard of this many times from PUG owners in several different Forums. But most seem to be related to their Dealer, or Jiffy-lube type changes. I have not heard of any damage to their engines caused by it. But too much engine oil in some engines, can cause the crankshaft hitting the oil and causing aeration, which is not good. But the 3.6 PUG, doesn't seem to be affected by this.
Great call on the PUP 5W30 engine oil. I am running this is several of our 3.6 engines. But everybody to their own.........

 

[Stan H]

Yeah, 5 qts cold is exactly at the top of the fill range on the dipstick on mine.

Good observation. Mine, 2023, 5 qts. is exactly at the full fill mark, which it should not be when cold. "Cold" in this instance meaning after an oil change, and adding a 5 qt. jug, then waiting fine minutes or longer.

So, is Stellantis increasing profits little by little, like a cm of cable at a time? Joking, but, maybe not...

Only if they own a big portion of the oil companies or the outfit that makes the cable for the dipsticks

 

[Alan_Hepburn]

But too much engine oil in some engines, can cause the crankshaft hitting the oil and causing aeration, which is not good. But the 3.6 PUG, doesn't seem to be affected by this.

Isn't that what the windage tray is designed to prevent? Don't most modern engines use a windage tray?

 

[ShadowsPapa]

Isn't that what the windage tray is designed to prevent? Don't most modern engines use a windage tray?

They do - but it's to prevent the "wind" from the spinning shaft of acting like the wind on the ocean - whipping up and aerating the oil surface.
And it prevents drag on the crankshaft.
But if an engine is overfilled by "too much" even that won't matter.

1 quart is almost never a problem. Most engines are designed to be able to handle that little extra.

And as pointed out here - some even suggest 1 extra quart when racing -

https://www.jeepgladiatorforum.com/...art-cause-a-seal-leak-heres-some-facts.98346/

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