Maximize 3.6 Reliability

[Jeep Dude]

The engine in the JL is very different than the previous Gen. many many internal changes and was actually designed around 0w20. One of the few engines where the recommended viscosity doesn’t vary by country/region. It’s 0w20 world wide for the pug motor

Run 5W-30 or 0W-30 oil and change every 5K miles.

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[1BadManVan]

Well ones a fact and ones an opinion lol. If an engine was originally designed around a thicker grade and they changed it for Cafe reasons, then that’s one thing. But if they redesign an engine specifically around a thinner viscosity, then that means the oil passages and other tolerances in the motor were made around that weight of oil.

That’s why the PUG motor specifically also calls for the same weight of oil world wide. That to me says a lot about how they designed the motor because majority of engines will still call for a thicker grade in other countries

Will you kill the engine going a bit thicker? No, they still have certain tolerances to abide by since not all 20 grade oils are exactly the same viscosity, some brands run thicker than others. But 0w20 is definitely a safe bet to run in these as this wasn’t just a random viscosity change one year, this was a redesign

 

[Dusty Dude]

If you run a catch can, make sure it's NOT a UPR which has a crappy hose design and will crack and leak on your passenger oxygen sensor and ruin it.

Oh, great, now you tell me… I just ordered one!

 

[Tncdrew]

Walnut blasting the backside of the valves is not needed--the 3.6L is an MPI engine, not DI. Use a good fuel injector cleaner frequently.

Run 5W-30 or 0W-30 oil and change every 5K miles.

Run an oil filter which can filter down to 20 microns @ 99% efficiency. Take EXTREME care not to overtighten the oil filter cap.

Run a top quality air filter--not a K&N type.

If you run a catch can, make sure it's NOT a UPR which has a crappy hose design and will crack and leak on your passenger oxygen sensor and ruin it.

Change your axles and transfer case fluid early and often. Use 75W-140 in the axles despite what FCA says. If a Rubicon, pot the locking sensors with epoxy at 5K miles when you change fluid for the first time.

Change your automatic transmission fluid and filter at 50K miles and perform 3 or 4 dump and fills within the next 10K miles to replace nearly all of the old fluid.

Be prepared to change your auxiliary battery in about 3 years or less. Change both batteries when you do.

Drive your Jeep frequently and enjoy!

I ?% agree with every point made here.
Good advice!

 

[CarbonSteel]

There has never been an engine made that cannot run thicker oil--the passages in the PUG are no different than any other engine and the climate typically dictates the viscosity on the left side of the "W" which is the winter rating, not weight. In addition, there are thick xW-20 oils and thin xW-30 oils. The engine cannot tell the difference. Case in point:

There are two values that I look at in an oil to understand its true viscosity and that is the Kinetic Viscosity (KV) @ 100°C and the HTHS number (not all oils publish this one and some are just baseline numbers).

For example, here is the typical KV and HTHS numbers for 3 different viscosity ranges:

Oil Brand	Viscosity	Minimum KV @100°C	Maximum KV @100°C	HTHS @ 150°C
---	xW-20	5.6	9.3	2.6
---	xW-30	9.3	12.5	2.9
---	xW-40	12.6	16.3	3.7

Here are the same values for specific brands and 0W-20 viscosities which are ranked from thinnest to thickest within the same viscosity. Havoline is the thinnest 0W-20 and Redline is the thickest (using the KV numbers):

Oil Brand	Viscosity	KV @100°C	HTHS @ 150°C
Havoline Pro-DS	0W-20	8.0	---
Castrol Edge	0W-20	8.2	2.6
Quaker State FS	0W-20	8.3	---
Rotella Gas Truck	0W-20	8.4	---
Valvoline Extended Protection	0W-20	8.4	2.7
Pennzoil Platinum	0W-20	8.6	2.6
Mobil 1 Extended Performance	0W-20	8.6	---
Kendall GT-1	0W-20	8.8	2.6
Redline Synthetic	0W-20	9.1	2.9

Likewise, from the 5W-30 perspective, Castrol Edge is the thinnest and Mobil 1 ESP is the thickest and the Castrol Edge is what I would consider very close to a thick 0W-20 (KV maximum is 9.3) whereas the Mobil 1 ESP is almost a thin 0W-40 (KV minimum is 12.6).

Oil Brand	Viscosity	KV @100°C	HTHS @ 150°C
Castrol Edge	5W-30	10.0	3.0
Pennzoil Platinum	5W-30	10.3	---
Mobil 1 Extended Performance	5W-30	10.6	---
Valvoline Extended Protection	5W-30	10.7	3.2
Havoline Pro-DS	5W-30	10.8	---
Kendall GT-1	5W-30	11.0	3.1
Quaker State FS	5W-30	11.6	---
Rotella Gas Truck	5W-30	11.7	---
Mobil 1 ESP	0W-30	12.0	3.5
Mobil 1 Euro	0W-40	12.9	---

As you can see, there are and can be vast differences in oils which have a 0W-20 or 5W-30 viscosity, and this is why I call BS that the 3.6L VVT is "viscosity sensitive"--there are too many variations in xW-20 alone for that to be true.

There are oils which carry 0W-20 viscosity rating that can almost be a 5W-30 and there are 5W-30 oils which can almost be a 0W-20.

I have a friend in Texas who has ran 0W-40 in his 2019 since the first oil change and over 100K miles later it runs just fine.

My recommendation for xW-30 is to provide more protection and less wear than a xW-20 and on that point it is a fact and not an opinion.

 

[CarbonSteel]

Oh, great, now you tell me… I just ordered one!

A few of us have had the hose on the PCV crack and leak. UPR has replaced the hose with no issue, but that doesn't fix the ruined O2 sensor.

 

[CarbonSteel]

One is for fuel economy and the other for higher levels of protection and reduced wear.

Pick your poison...

 

[nositting]

Walnut blasting the backside of the valves is not needed--the 3.6L is an MPI engine, not DI. Use a good fuel injector cleaner frequently.

Run 5W-30 or 0W-30 oil and change every 5K miles.

Run an oil filter which can filter down to 20 microns @ 99% efficiency. Take EXTREME care not to overtighten the oil filter cap.

Run a top quality air filter--not a K&N type.

If you run a catch can, make sure it's NOT a UPR which has a crappy hose design and will crack and leak on your passenger oxygen sensor and ruin it.

Change your axles and transfer case fluid early and often. Use 75W-140 in the axles despite what FCA says. If a Rubicon, pot the locking sensors with epoxy at 5K miles when you change fluid for the first time.

Change your automatic transmission fluid and filter at 50K miles and perform 3 or 4 dump and fills within the next 10K miles to replace nearly all of the old fluid.

Be prepared to change your auxiliary battery in about 3 years or less. Change both batteries when you do.

Drive your Jeep frequently and enjoy!

i use the 0w20, but other than that, i do this exactly and feel it’s excellent advice. i’m not an engineer or mechanic, just a regular guy.

 

[nositting]

only other thing i’d probably add is to rotate the tires every 5,000 miles. not really an engine thing but good to do. also, torque with a torque wrench. not hard to do at all. these things don’t need crazy stand on breaker bar torque.

 

[Dusty Dude]

A few of us have had the hose on the PCV crack and leak. UPR has replaced the hose with no issue, but that doesn't fix the ruined O2 sensor.

Thanks for letting me know. I will have to keep an eye on it.

 

[Jeep Dude]

One is for fuel economy and the other for higher levels of protection and reduced wear.

Pick your poison...

Redline 0w20 it tiz ??.

The chart you posted confirms and supports even further, a nice conversation I had with a Redline Oil engineer circa 1990. He literally convinced me to drop an entire viscosity grade, over what was recommended, for my track car. A custom Turbocharged BMW (over 500rwhp, back in the 80's FWIW). This was during a period, when everybody swore by 20w50 or 15w50 lol.

His reasoning at the time, was that indeed their viscosities were thicker than the entire competition(at that time), and that I would see a slight drop in oil temps by following his recommendation, ditto unnecessary drag.....

Turns out he was right, per my custom VDO gauges. I was totally blown away.

Coming back to present day, I will transition over to the Redline 0w20, from the O.E Penzoil 0w20, as I approach warranty end .

I'm keeping this vehicle for the long haul, just to see, how long it lasts.

 

[CarbonSteel]

Thanks for letting me know. I will have to keep an eye on it.

It took less than 40K miles on mine.

 

[Tncdrew]

Coming back to present day, I will transition over to the Redline 0w20, from the O.E Penzoil 0w20, as I approach warranty end .

Just curious as to why changing from one brand of a specific weight, to another brand (same weight) would not be done until "warranty end"?

 

[Jeep Dude]

Just curious as to why changing from one brand of a specific weight, to another brand (same weight) would not be done until "warranty end"?

Good question, and I'm a bit embarrassed to admit, that what I will say, is very uncharacteristic of me, as usually, I wouldn't give a rats ass.

I have somehow now become more paranoid(older age?) than I used to be, thanks or no thanks to the constant reviews on this forum, of $tealerships refusing powertrain powertrain warranties, over various stupid reasons.

Secondly, to add to the above, Redline is a Group V oil, not your typical hydrocracked synthetic, so it would be quite easy, to pinpoint this, in a push comes to shove situation. Yeah, I know, the chances of that occuring might be nil, but nonetheless..

Also, Penzoil seems to have a pretty good reputation, and lately, they began that registration/warranty thingy, so surely they must be confident in their product? I'm therefore not in a desperate rush, to make the switch. Also, unlike my aforementioned sports cars, I really drive the Jeep's engine "gently". You know, elbow over window sill, hat on, top down, just crusin' along ???.

I have begun to flog it a bit more aggressively as of late over the rougher terrain, now that I'm 100% fully cloaked to the hilt, and new tougher shocks on, but the engine, unlike the chassis, doesn't get much action.

Speaking of "warranty end", if it makes you feel any better in trying to convince me to ditch the Penzoil 0w20 like today, I've only got like 18000 miles on my odometer. As far as chronology is concerned, about 1 year remains on the powertrain warranty, since mine is a 2019.

I figure 1 more year won't hurt ? ?‍

 

[CarbonSteel]

To determine how much "better" any oil that meets specifications is versus any other would require hundreds of thousands, if not millions, of dollars of specialized equipment that I would opine none of us have or have access to.

It would also require test controls that none of us have or can follow. Use any specified oil and carry on or up the viscosity if you want a bit more protection.

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