Curious about the 3.2 vs. 3.6 Oil Specs

[talljeeper]

My Mrs. has a '21 Cherokee with the 3.2 (great engine). My Gladiator has the 3.6. The oil spec with the 3.2 is 5w20, as we all know the the 3.6 is 0w20.

I just thought it was interesting that essentially the same design of engines require different viscosity. My hunch is EPA related. The Cherokee consistently gets close to 30 MPG...well my Gladiator not so much LOL Yes, I realize weight to HP is way different as well as displacement.

I am running Amsoil Signature 5w20 in my 3.6 and Amsoil top end lubricant every other tank. My 3.6 is whisper quiet and smooth by switching to this combo. Also noted that the 3.2 has similar cam and oil filter/cooler issues like the 3.6.

Just curious..thats all.

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[jebiruph]

I think the Cherokee 3.2 is based on the older 3.6, not the upgraded 3.6 in the JL and JT that uses the different oil.

 

[ShadowsPapa]

My Mrs. has a '21 Cherokee with the 3.2 (great engine). My Gladiator has the 3.6. The oil spec with the 3.2 is 5w20, as we all know the the 3.6 is 0w20.

I just thought it was interesting that essentially the same design of engines require different viscosity. My hunch is EPA related. The Cherokee consistently gets close to 30 MPG...well my Gladiator not so much LOL Yes, I realize weight to HP is way different as well as displacement.

I am running Amsoil Signature 5w20 in my 3.6 and Amsoil top end lubricant every other tank. My 3.6 is whisper quiet and smooth by switching to this combo. Also noted that the 3.2 has similar cam and oil filter/cooler issues like the 3.6.

Just curious..thats all.

Fun, another oil thread................

I've always run exactly what the book says to run in my Jeeps. Mine are quiet as they should be - in fact, twice I've gotten out forgetting to shut it off. Hey, its' still running - didn't notice until I started to get out.
5w20 actually overlaps the 0w20 spec in many ways. If you look carefully at viscosity specs and charts, the 0 to 5 WINTER number overlap each other.
Funny thing is - you've not really changed much of anything. The W is the cold number, winter number. The 20 is the same.
Putting something in the gas tank only lubes where the fuel can go. So maybe you've quieted down the injectors a bit. It won't have any impact on valves or cams or that sort of thing. The fuel mixture doesn't get out of the intake or combustion chamber, so can't really do a lot to quiet much in that respect.

Do what makes you feel good, I guess.
I follow the book and have been just fine for many years with our 3.6s in various Jeeps.


Don't even think of trying to compare MPG on two totally different shaped vehicles with different drive trains and more. Just don't go there!!

The Cherokee consistently gets close to 30 MPG...well my Gladiator not so much LOL Yes, I realize weight to HP is way different as well as displacement.

Gotta laugh at that. A brick sitting tall in the air with a VERY different engine - it's not just displacement, and different gearing and shape and drag numbers.
It's like comparing a bullet to a brick going through the air.


Honda 2.0 litre goes the quarter mile and hits 180 mph
Gremlin, stripped down to almost nothing but a sheet metal shape, sitting with a heavily modified aluminum 401 cid engine hits 180 in the quarter mile.

Get your slide rules out.

 

[talljeeper]

Fun, another oil thread................

I've always run exactly what the book says to run in my Jeeps. Mine are quiet as they should be - in fact, twice I've gotten out forgetting to shut it off. Hey, its' still running - didn't notice until I started to get out.
5w20 actually overlaps the 0w20 spec in many ways. If you look carefully at viscosity specs and charts, the 0 to 5 WINTER number overlap each other.
Funny thing is - you've not really changed much of anything. The W is the cold number, winter number. The 20 is the same.
Putting something in the gas tank only lubes where the fuel can go. So maybe you've quieted down the injectors a bit. It won't have any impact on valves or cams or that sort of thing. The fuel mixture doesn't get out of the intake or combustion chamber, so can't really do a lot to quiet much in that respect.

Do what makes you feel good, I guess.
I follow the book and have been just fine for many years with our 3.6s in various Jeeps.


Don't even think of trying to compare MPG on two totally different shaped vehicles with different drive trains and more. Just don't go there!!



Gotta laugh at that. A brick sitting tall in the air with a VERY different engine - it's not just displacement, and different gearing and shape and drag numbers.
It's like comparing a bullet to a brick going through the air.


Honda 2.0 litre goes the quarter mile and hits 180 mph
Gremlin, stripped down to almost nothing but a sheet metal shape, sitting with a heavily modified aluminum 401 cid engine hits 180 in the quarter mile.

Get your slide rules out.

The upper cylinder lube definitely made a difference on injector tick. I knew you would love this post Papa.

 

[JTDay]

I haven't seen anything to support running anything other than 0w20. Just the way it is. Unless people start racing with 3.6 pentas and discovering modes of failure directly related to oil viscosity, anything anyone says on oil viscosity for these is hearsay. Sorry to all the 5w30 drum beaters.

 

[Kirk*Mojave]

Oil threads always turn ugly...

 

[Hootbro]

The 3.2L Pentastar always struck me as a weird choice of even why they only make and put it in the Jeep Cherokee?

 

[ShadowsPapa]

The upper cylinder lube definitely made a difference on injector tick. I knew you would love this post Papa.

Your post adds to my thinking - I wonder if some of what at least a few people here is injector tick.
My 4.0 is a loud engine - granted, with the comp xtreme 4x4 cam the valve train isn't quiet, I think some of the noise is injector sounds.
Normally those injectors just sit there, dry, in a sense, as gasoline isn't a lubricant, and smacks up and down.
Sounds like it's a good commercial for the lube - quiets injectors if nothing else (can't hurt valves, I suppose)

 

[Mr._Bill]

I started using the Sea Foam Injector Cleaner and Lube a few years ago after the dealer tried to sell me some expensive Injector Cleaning service. Both of my trucks have had quiet engines. I run it down near a 1/4 full, and then add a bottle when I fill up. Occasionally (about every 3k miles), I'll pour a 20oz can of the Sea Foam Motor Treatment in the tank. I shop Walmart and Amazon for the lowest price. Last purchase was a 24 count box from Amazon for $86.06 delivered.

Sea Foam IC5 Fuel Injector Cleaner, 5.25 oz https://a.co/d/8Sx8Fif

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