OIL, 0-20 or otherwise (couldn't find the other oil threads)

[ShadowsPapa]

My other cars are Subarus. I guess I was applying what they have done. I know there are other manufacturers doing the same thing. Maybe Jeep is an outlier in that respect?

I'm still using the theory of oil viscosities and temps and applying them to my climate.

It's engine operating temperature. Once warmed up, the oil and engine don't give a rip about your climate. Only the cold starts will matter - your "W" number before the last number.
Going from 0w to 5w for example.
But the latter number, won't matter. Once the oil is warmed up, that's the temperature it operates at whether the ambient temp is 50 or 95.

Today, ambient temperature of 60 degrees, I was seeing 210 degrees coolant AND oil and 190 degree transmission temps. Those all varied with the hill, speed and so on.
If you oil is running at 195 degrees, that's all it cares about. Not where you live.

OTOH, last I heard, the sky in florida is still in place, hasn't fallen.

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[Hootbro]

My other cars are Subarus. I guess I was applying what they have done. I know there are other manufacturers doing the same thing. Maybe Jeep is an outlier in that respect?

I'm still using the theory of oil viscosities and temps and applying them to my climate.

I made the same mistake also thinking that coming from Toyota's that would also list multiple oil grades in other markets.

Starting with my wife's then owned 2016 Jeep Renegade with the 2.4L Tigershark engine, I went down a rabbit hole looking at other markets for alternate oil grades and the same thing, globally it was one single grade. I think it is a FCA/Stellantis thing to call out one oil grade globally rather than multiple oil grades.

FWIW, multiple people to include me have use alternate thicker oil grades in the 3.6L Pentastar without issue or detriment, but only the 0W-20 call is approved and all data suggest it is sufficient.

 

[Stan H]

It's engine operating temperature. Once warmed up, the oil and engine don't give a rip about your climate. Only the cold starts will matter - your "W" number before the last number.
Going from 0w to 5w for example.
But the latter number, won't matter. Once the oil is warmed up, that's the temperature it operates at whether the ambient temp is 50 or 95.

Today, ambient temperature of 60 degrees, I was seeing 210 degrees coolant AND oil and 190 degree transmission temps. Those all varied with the hill, speed and so on.
If you oil is running at 195 degrees, that's all it cares about. Not where you live.

OTOH, last I heard, the sky in florida is still in place, hasn't fallen.

Sounds mirror to my temps 208 water , 203 oil 192 transmission pulling a 1 mile hill grade probably 8 -9degrees in 7th, 6th then 5th topping hill at 65mph. Oil pressure 78 then dropped to 77 before topping out.

 

[ShadowsPapa]

ALL THREE (3) of my JTs will run from 190 to about 220 degrees, depending on when you look, speed, going up a hill and so on.

Ambient temps in the 59-60 range (which really won't matter unless your cooling system just can't keep up) - but my point on the ambient temp being so low is that what matters to the oil is the engine temperatures. That is determined by load, oil viscosity (thicker tends to run hotter due to slower flow and more sheer forces)
So if I'm at 60 degrees and see 2010 or so engine temperatures and oil temperatures, and someone at 90 degrees is seeing 210 temps.......that's all the oil cares about.

The front number we can ignore for the most part - that's W for Winter. It's the viscosity when COLD. If you live where it gets REALLY cold, you want a lower number there, if it never gets really cold and your night time temps maybe never get below 60, you don't care about a 0W oil, 5W maybe even 10W is ok.
The back number - after the W, is taken at 210 degrees (gee, that's a pretty typical coolant and oil operating temperature - is that why they chose that number - hmmmm)

Going with a higher front number can matter if you go out and it's 40 degrees - you have a thick oil, and it won't flow as fast or easily to where it needs to be. You can start things like the - CAM lobes.

Going with a higher back number isn't really doing much of anything unless you run your engine a lot more hot than we do here. That back number is for when the engine is warmed up, the oil is warmed up, and 210 degrees.

So again, do whatever, but I can't see anyone making a lick of difference anywhere other than perhaps slowing down the protection on a cold start first thing in the AM.

(side note - my 25 runs higher oil pressure when hot/warmed up - I see 32-33 where with my others, it was 29-30. I'll be keeping watch on that as it "wears in")

 

[Batterycap]

Interesting how GM just flips a switch when it is convenient for them to go from 0W-20 to 0W-40.

Nothing wrong with sticking to 0W-20 as recommended in the owners manual, but I have been running 5W-30 the last couple of oil changes after dumping the factory fill and am currently running 5W-40 Euro spec oil and probably will for the remainder of the summer.

I am sure some shrieking violets will be along to having a contrary opinion on that and that is fine. I am not risk adverse over it nor claim anyone should follow what I do.

Note the specs met in the description of each oil. I have seen a few fellow Jeep owners going th Schaeffer's. Comparatively expensive.

 

[ShadowsPapa]

Note the specs met in the description of each oil. I have seen a few fellow Jeep owners going th Schaeffer's. Comparatively expensive.

I used to buy their chain lube by the case - I had a high-boy corn sprayer that was chain drive from the jackshafts down to the wheel drive cases. You didn't want to replace that expensive chain, so I kept cans of their lube in the thing.

 

[Stan H]

ALL THREE (3) of my JTs will run from 190 to about 220 degrees, depending on when you look, speed, going up a hill and so on.

Ambient temps in the 59-60 range (which really won't matter unless your cooling system just can't keep up) - but my point on the ambient temp being so low is that what matters to the oil is the engine temperatures. That is determined by load, oil viscosity (thicker tends to run hotter due to slower flow and more sheer forces)
So if I'm at 60 degrees and see 2010 or so engine temperatures and oil temperatures, and someone at 90 degrees is seeing 210 temps.......that's all the oil cares about.

The front number we can ignore for the most part - that's W for Winter. It's the viscosity when COLD. If you live where it gets REALLY cold, you want a lower number there, if it never gets really cold and your night time temps maybe never get below 60, you don't care about a 0W oil, 5W maybe even 10W is ok.
The back number - after the W, is taken at 210 degrees (gee, that's a pretty typical coolant and oil operating temperature - is that why they chose that number - hmmmm)

Going with a higher front number can matter if you go out and it's 40 degrees - you have a thick oil, and it won't flow as fast or easily to where it needs to be. You can start things like the - CAM lobes.

Going with a higher back number isn't really doing much of anything unless you run your engine a lot more hot than we do here. That back number is for when the engine is warmed up, the oil is warmed up, and 210 degrees.

So again, do whatever, but I can't see anyone making a lick of difference anywhere other than perhaps slowing down the protection on a cold start first thing in the AM.

(side note - my 25 runs higher oil pressure when hot/warmed up - I see 32-33 where with my others, it was 29-30. I'll be keeping watch on that as it "wears in")

On a pull up steep grade will yours get warm enough to kick the fan in ?
On my site there is a super steep grade that I can only pull 3rd gear low side or 1st gear high side nearly to the floor in 2 spots and by the time I crest I will normally be between 225-228-230 seen 231 once and with in seconds of each of those temps the fan will kick in high side and bring down quickly.
Also to leave this county ypu go through 2 long valleys and it accesses the highway at the foot of a mile long grade of greater than 6% literally you start straight into a pull . Every single time I reach the top the truck will be at 230 and fan will kick in doing 60-65 in 5th gear won't pull it in 6th.
Ambient temps here have been 73-84 .
I replaced water pump and thermostat and temp sensor (bearing went out) and replaced reservoir bottle (top hose connector broke) . Temp sensor was dirty. Ever since then it seems like I run about 10 degrees warmer than before.

BEFORE all those repairs in low pulling 19% grade on dirt spinning hard up hill in summer it would make fan come on which is similar to this site cause it Crest out so steep you can't see over the top you literally top over & come down on faith of course Im crazy like that.
But I dont recall except when pulling my pop up that fan ever kicked on in 80degree weather . Had several 90degree days last year that it did it on the same highway hill pull.
Could it be my temp sensor was just dirty and wasn't reading exactly correct or could this thermostat be stiffer ?

 

[ShadowsPapa]

On a pull up steep grade will yours get warm enough to kick the fan in ?
On my site there is a super steep grade that I can only pull 3rd gear low side or 1st gear high side nearly to the floor in 2 spots and by the time I crest I will normally be between 225-228-230 seen 231 once and with in seconds of each of those temps the fan will kick in high side and bring down quickly.
Also to leave this county ypu go through 2 long valleys and it accesses the highway at the foot of a mile long grade of greater than 6% literally you start straight into a pull . Every single time I reach the top the truck will be at 230 and fan will kick in doing 60-65 in 5th gear won't pull it in 6th.
Ambient temps here have been 73-84 .
I replaced water pump and thermostat and temp sensor (bearing went out) and replaced reservoir bottle (top hose connector broke) . Temp sensor was dirty. Ever since then it seems like I run about 10 degrees warmer than before.

BEFORE all those repairs in low pulling 19% grade on dirt spinning hard up hill in summer it would make fan come on which is similar to this site cause it Crest out so steep you can't see over the top you literally top over & come down on faith of course Im crazy like that.
But I dont recall except when pulling my pop up that fan ever kicked on in 80degree weather . Had several 90degree days last year that it did it on the same highway hill pull.
Could it be my temp sensor was just dirty and wasn't reading exactly correct or could this thermostat be stiffer ?

Can't say- never really paid attention to fan noise. The Jeeps were too loud to notice anyway. This 2025 is a whole lot quieter than the others.
I've noticed mine gets up into the 200s, say 220, then suddenly drops way down again into the mid 190s, then up then down, so must be the fan kicking in. But I haven't listened for it - I've only noticed the temps vary a lot on longer drives - from the lower 190s to about 220, back and forth.
Maybe I'll have to see if I can monitor the fan via JSCAN and sort of keep track.

Only sound I've really noticed about this 25 is that the air intake is much louder than my prior two. You can really hear it growl at about 2,000-2,200 RPM under a load, never heard that with the other two. This has more engine growl for some reason. (Maybe it's a Mojave feature!)

 

[Deleted member 67086]

Interesting watching a non-Jeep mechanic’s steps for diagnosing the issue. When he started the Jeep, my thought was, step 1, pull the valve cover. A number of people posting comments felt the same way.

 

[ShadowsPapa]

Interesting watching a non-Jeep mechanic’s steps for diagnosing the issue. When he started the Jeep, my thought was, step 1, pull the valve cover. A number of people posting comments felt the same way.

"customer says check engine light has been on for a couple of weeks" WTF? And you just kept going and going? Doctors and service advisors always ask me "so when did this start" and you'd better not say "oh, a couple of weeks ago" or you'll get this well-deserved "look".

It's not really hard to diagnose in some respects, but there's also a more complex method as well that gets into checking for stuck or hanging up VVL followers, control solenoids and so on.

At times I sort of wonder if part of the issue starts out really simple - VVL misbehaving, and that turns into cam issues later. For example - when one follower is deemed by the PCM to be stuck in high lift, it puts them all in high lift mode, so now you are driving with the followers working more like flat tappets that are stuck and can't rotate at all times. But that's supposed to set a MIL if I recall........ I'd have to go back into the documents - it gets rather deep.

But there are ways to tell - watch the MAP for one thing. If you have one or more cylinders with worn down lobes, the air flow into the intake will be uneven. Sort of like diagnosing legacy engine cam issues using a vacuum gauge...........

The damage is always on the high lift side of things, so technically, there should be no issues at idle or low loads or interstate cruising speeds! If there are - it makes me wonder if it was stuck in high lift mode and that's what killed it.
These stay in low lift mode unless power is needed, or above certain RPM, so why would the high lift portions trigger some of the stuff we see when it should be in low lift at those times?

Man, where's Charles when you need him.

 

[Deleted member 67086]

"customer says check engine light has been on for a couple of weeks" WTF? And you just kept going and going? Doctors and service advisors always ask me "so when did this start" and you'd better not say "oh, a couple of weeks ago" or you'll get this well-deserved "look".

It's not really hard to diagnose in some respects, but there's also a more complex method as well that gets into checking for stuck or hanging up VVL followers, control solenoids and so on.

At times I sort of wonder if part of the issue starts out really simple - VVL misbehaving, and that turns into cam issues later. For example - when one follower is deemed by the PCM to be stuck in high lift, it puts them all in high lift mode, so now you are driving with the followers working more like flat tappets that are stuck and can't rotate at all times. But that's supposed to set a MIL if I recall........ I'd have to go back into the documents - it gets rather deep.

But there are ways to tell - watch the MAP for one thing. If you have one or more cylinders with worn down lobes, the air flow into the intake will be uneven. Sort of like diagnosing legacy engine cam issues using a vacuum gauge...........

The damage is always on the high lift side of things, so technically, there should be no issues at idle or low loads or interstate cruising speeds! If there are - it makes me wonder if it was stuck in high lift mode and that's what killed it.
These stay in low lift mode unless power is needed, or above certain RPM, so why would the high lift portions trigger some of the stuff we see when it should be in low lift at those times?

Man, where's Charles when you need him.

Pretty sure when they say the check engine light has been on for two weeks, it’s actually been four to six weeks. Kind of like you friend who’s always late when they say they’ll be there in 5-minutes.

 

[Hootbro]

customer says check engine light has been on for a couple of weeks" WTF? And you just kept going and going? Doctors and service advisors always ask me "so when did this start" and you'd better not say "oh, a couple of weeks ago" or you'll get this well-deserved "look".

If I was to make a observational guess, less than 50% of men and maybe 10% of women are savvy enough to know the implications of driving with a MIL on for extended lengths.

If the vehicle goes when they press the gas pedal, they send it and it becomes a later problem to figure out.

 

[ShadowsPapa]

If I was to make a observational guess, less than 50% of men and maybe 10% of women are savvy enough to know the implications of driving with a MIL on for extended lengths.

If the vehicle goes when they press the gas pedal, they send it and it becomes a later problem to figure out.

Can't say that's true or not - but if a light comes on that's not normally on, my wife demands it be checked instantly if not sooner. "There's something wrong, that isn't normally on".
With the commercials on TV for those service plans - I'd think people would really be freaking out - OMG! My check engine light is on! She's gonna blow!" (that's what those TV ads tell me!)

 

[Hootbro]

Interesting watching a non-Jeep mechanic’s steps for diagnosing the issue. When he started the Jeep, my thought was, step 1, pull the valve cover. A number of people posting comments felt the same way.

I am sure all the Jeep people were screaming in the comments that Ivan should have went straight to the valve covers but that overlooks that Ivan works a bazillion different makes and models in his business and I would cut him the slack for not knowing to go the RH head valvetrain. If anything, he followed his process that shows his skills that is going to lead him there anyway.

As to why his scan tool shows misfires on LH drivers bank is interesting though. I am almost wondering if it is his scan tool leading him astray?

 

[Deleted member 67086]

If I was to make a observational guess, less than 50% of men and maybe 10% of women are savvy enough to know the implications of driving with a MIL on for extended lengths.

If the vehicle goes when they press the gas pedal, they send it and it becomes a later problem to figure out.

I am sure all the Jeep people were screaming in the comments that Ivan should have went straight to the valve covers but that overlooks that Ivan works a bazillion different makes and models in his business and I would cut him the slack for not knowing to go the RH head valvetrain. If anything, he followed his process that shows his skills that is going to lead him there anyway.

As to why his scan tool shows misfires on LH drivers bank is interesting though. I am almost wondering if it is his scan tool leading him astray?

Oh I was by no means being critical of his approach. I’m a follower of his channel and enjoy how analytical he is. Agreed , his process led him to the right place.

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