I put in a question to both Jeep and Mobil1. We will see if I get any answers.

 

From my tribology class in school, I learned that all automotive crankshafts are externally pressurized. The viscosity comes into play, but I was surprised to find that the amount of force that can be distributed by a mere 10 microinches (1/100000 inch) of film thickness. The more important consideration is oil pressure.

Having said that, I am confident that the engine designers took the viscosity into consideration when they selected 5W-20.

I also use the synthetic due to its more consistent physical properties over the life of the oil change and oil temperature.

 

I am not sure which Mobil site you are checking. When I checked it they are recommending 5w-30 (not 10w-30).

Mobil 1 Recommendation

These links have been posted on here a couple times, but here they are again:

EPA Letter - CAFE

TSB Patriot Europe

Machinery Lubrication Article


.

 

they are recommending 5w-30 (not 10w-30).

Yes, my bad. That is what I saw too.

EPA Letter - CAFE

From what I see, this letter clearly links 5W20 to CAFE gas mileage, but I don't see anything that implies lack of lubrication.

TSB Patriot Europe

This one is the most persuasive. The problem is there is no explanation why the change. As some had said, they thought it had to do with the speeds on the autobahn.

Machinery Lubrication Article

There are many articles like this on the internet. Some of them are copy and pasted word for word. They make perfect sense but are a little inconclusive. Their bottom line is...

The best oil for your vehicle depends on your driving habits, the age of your engine and the climate you drive in, but it is not necessarily the type of oil specified in the owner’s manual or stamped on the dipstick.

So, if you tow something or spend most of your time on the highway in 100 degree temps, you should probably go with a heavier oil. If you are driving around town with 10 degree temps, you should go with a lighter oil.

You know what, I'm probably making too big a deal about this. Maybe I should go with the 5W20 in the winter and 5W30 in the summer.

Some people have stated that with our lifetime warrentees, if the engine has problems we'll just get new ones. Well that's not quite the way it works. When something goes wrong, they will fix what is wrong and nothing else. If one rod bearing spins, they will replace that and probably nothing else and they'll hope you get sick and tired of messing with it rather that bring it back again. That's just the way it is. Any work they do for free is going to be minimal.

That being said, maybe I'll just go with the 5W30 all year.:smiley_thumbs_up:

 

This one is the most persuasive. The problem is there is no explanation why the change. As some had said, they thought it had to do with the speeds on the autobahn.

My problem with the autobahn argument is, what about those in the rest of Europe (and England) where the speed limits are more or less comparable to the US?

I do agree with individual driving requirements and situations...the oil on a loaded down Pat with 5 adults (and no oil cooler package) driving in the mountains during an August heatwave is going to be significantly more stressed than a Pat driven on flat land in cool weather (oil cooler or not)...

 

I have sent in an email request to Jeep asking them specifically and only if 5w30 would void the warranty. I did this via e-mail so they will have to respond in writing. I am crossing my fingers for a clear reply, but am not holding my breath.

I have an FDII, so I also have an engine oil cooler. I am hopeful this combined with synthetic 5w20 will give me a good deal more protection over conventional 5w20.

There is a fairly persuasive argument that others have brought that 5w30 is a better option.

The autobahn argument makes sense but the problem is that it is isn't verified. It makes sense that the same warning would go to all of Europe, even Britian as they are a union now and probably gets a blanket ruling for the entire continent.

If I get an all clear from Jeep, I will go with 5w30, short of that I just don't know.

I read the manual and I don't see a real clear statement either way. I will have to read the warranty booklet again and see if that gives permission to use 5w30.

 

The CAFE story is BS. Think of it this way... IF 5w20 increases gas mileage, the only way it can do that is by reducing engine friction as opposed to 5w30. Since friction is the enemy of any machine 5w20 is a better oil. Just because the oil is of a "lighter" spec, does not mean that it is proving LESS protection.


The whole temperature thing does not apply either if you use synthetic oil. IE Mobil 1 5w20 is not going to break down at 100mph as opposed to conventional 5w30.

 

The CAFE story is BS. Think of it this way... IF 5w20 increases gas mileage, the only way it can do that is by reducing engine friction as opposed to 5w30. Since friction is the enemy of any machine 5w20 is a better oil. Just because the oil is of a "lighter" spec, does not mean that it is proving LESS protection.
.

It's not friction, it is the power required to pump a viscous fluid and shear stress...the oil pump mainly, but all parts that rotate or move on an oil film are subject to sheer stress, which is increased as the viscosity is increased.

This is even more pronounced the tighter the gap is between the parts (the argument is often made that new engines have tighter tolerances, blah blah), then the sheer stress differences between fluids of different viscosities are even greater, as sheer stress is inversely proportional to the distance between the moving planes (the parts lubricated by the oil).

This is why lower viscosity oils help with gas millage.

 

I think you all are making a big deal out of nothing. The manual says 5w-20 the oil fill cap says 5w-20 so thats what I'm going to use. I don't think jeep would have us use an oil that would harm the engine in some way. Plus synthetic oils are made to handle heat and all much better than regular oil. I am going to use mobil 1 full synthetic oil when its time to change 5w-20.

 

roberttroll and metalhead.......

thank you.

 

...let me jump into your discussion about Mobil recommendation for Europe. I just tried to find 5W-20 oil on Google.de (Germany) and Seznam.cz (Czech) and what a wonder, no hit!? All major manufactures (Mobil, Shell, Aral, Total, OMV, Exxon) don't offer this weight!? You can have 0W-40, 5W-30, 5W-40, etc., but not 5W-20. Sure you can imported from USA, but can you imagine the price?

 

With my Triumph motorcycle - the Spec from Triumph was Mobil 4T. It had no direct spec like you would see on an American oil can. You would either buy imported 4T or the next best thing was i think 5w50. Like the guy just posted below I bet there is no spec for 5w20 in Europe. So the Chrysler engineers are saying the next best thing that would be OK is 5w30.

Secondly you are all assuming that the European version has the same engine as the us version. They might share alot, but i can assure you they are not 100% the same engine. Emissions requirements are different.

About the oil pump thing - Sheer Stress IS friction. The only way for gas mileage to increase from one identical engine to the next is to lower internal friction. If 5w20 were providing less protection then it would be causing more wear and tear on internal parts = more friction = lower mileage.

That engineer who designed that engine said 5w20, and was so confident that the company is offering an unlimited mileage warranty. That should say enough.

 

The assumption is correct. The North American and Export engine/emissions components are 'exactly' the same. The export code (NA1) is not found anywhere in the parts listing (see below):

Jeep Patriot Parts Manual

The differences are with the starter, wiring, sensors, instructions, lighting and differential. Not the engine or emissions control. Do not forget Daimler Chryster are one company.

You are correct about "If 5w20 were providing less protection then it would be causing more wear and tear on internal parts = more friction = lower mileage." After several thousand km you would see very slightly more wear, hence a reduction in mileage. That is what is so ridiculous about allowing vehicle manufactures to use 5w-20 oil to reach their CAFE requirement.

Regarding protection of the engine there is evidence out there. Some of the oil analysis comparisons on Bob is the Oil Guy show a very slight increase in wear with 5w-20 vs 5w-30 all other things being equal.

Good point about the lifetime powertrain warranty, see the limitations though. Not sure they would replace your engine if it sustained wear/tear.

Still have yet to hear a compelling arguement for using 5w-20 when it is worse for the vehicle. This is a great thread, if anyone has anything else to add please let us know.

 

That engineer who designed that engine said 5w20, and was so confident that the company is offering an unlimited mileage warranty. That should say enough.
Reply With Quote

It really doesn't tell me much. It is a warranty for the first owner only. How many people own a car past 3 years, 5 years, 7 years. So, though it's a great deal for me who keeps his car forever, I only see it as a marketing ploy, not a show of confidence.

I'd like to see the figures to see how much will cost them compared to a 5 yr/ 60,000 mile warranty or 10 year/120,000 mile warranty.

I'm sorry, but I'm a cynic.

 

"Again, please show me the evidence that lower viscosity oils do not give better millage, and that higher viscosity oils will not protect parts better than a lower viscosity oil from wearing under stresses (thermal stress and mechanical forces), and then I might change my view."


5w20 gives the mileage that DC designed that engine to give. Show me where DC designed that engine to run on 5w30, and changed it to 5w20 because of CAFE.

 

Show me where DC designed that engine to run on 5w30, and changed it to 5w20 because of CAFE.

I never stated this, and I'm sure the use of 5w-20 falls into the design parameters...I personally don't want to be one the few percentile in that outer edge of the design parameter (warranty or not)...

Do you dispute any of my arguments presented (I am no expert), please tell me where I am wrong in my reasoning. To simply say that it says so in the manual and on the oil cap isn't convincing enough to me, based on the other evidence presented. That's pretty much the same as if I were to only point to the bullitin about the use of 5W-30 in europe and offer no other evidence to back it up.

Again, no-one is saying 5w-20 is "bad" for the engine, but that there might be something "better" out there, depending on ones driving habits and environmental conditions...that is all.

 

Some folks think we are splitting hairs.

I for one find these posts very interesting and informative so keep it up.

I have 6,000 miles to my next oil change to makeup my mind, so keep the info, opinions, and documents coming.

 

ExxonMobil's response to my question as to why their site recommends 5w30 when the manufacturer recommends 5w20.

"The Mobil website's recommendations are made by utilizing the
Automotive Checkcart catalog, it may be incorrect when it comes to
special and unique requirements or manufacturer's. This is why we state
always check your manufacturer's recommendations in the owner's manual.
If your jeep manufacturer recommends the 5W20 viscosity, stay with it.
Their is no less protection using the Mobil1 5W20 compared to
conventional 5W30 viscosity."

 

First off the European engine is different, slightly. You can check out the specs on the UK jeep web site and compare them to the US version. In the UK the 2.4l is rated at 168hp/162 lb ft torque. The us version is listed at 172hp/165lb ft torque. Straight from mother Jeep with no conversion. The weight is also different by about 4lbs. Do not know if that matters at all.

No i do not dispute what you are saying, i think what you are saying might apply to pre 2001 vehicles. 5w20 came out around 2001. There were many engines in 2000 with owners manuals that stated "use 5w30", and in 2001 the manuals stated "use 5w20". In that case, then maybee the manufacturer suggested changing for economy reasons. I say maybee because the reported increase in mileage is 1%. I think this is the core of the "5w20 conspiracy theory". There was no change in CAFÉ requirements in 2000-2001, and the fleet average did not change, so why did this magical oil suddenly appear?

Honda switched in 2001, and I think it is pretty well accepted that Honda makes one hell of a long lasting engine and I have yet to hear of a 2001 honda with a bad engine.

The GEMA engine was designed and built after the advent of 5w20. The goal of the platform was efficiency, so they designed the power train with that in mind. That engine was spec'ed, designed, built, and tested by professional automotive engineers who said use 5w20. They printed it in the owner’s manual, and on the dipstick. A few guys on a bulletin board said "5w20 is for CAFE, I know better than any XYZ automotive engineer". And I do not mean specifically on this board. The whole 5w20 thing is mentioned on many boards with the common theme being "the govt did it".

I know that a manufacturer is not going to possibly recommend something substandard to gain .2 mpg, especially when there was no requirement to do so. What makes more sense is the automotive companies asked the oil companies for a new grade of oil that flows better in modern engines with tighter fitting parts.

I could probably make a case for leaded gasoline using the same logic. It burns better, it has higher octane, and it lubricates "soft" valve seats. Does not matter though because a modern engine has no need for it.

So whatever you want to put in your engine is fine, i really do not care. But i will bet anyone that my quart of Mobil1 5w20 is light years ahead of any conventional 5w30 in terms of protecting my engine.

 

The engine and emissions are the same, the rating of hp/torque are not a result of differences in the engine as strange as that may sound. I know it may take a while, but review the PDF posted earlier to confirm.

I am on the same page as you when it comes to a "Government Conspiracy". They simply made a decision towards fuel economy in the short term vs long term. In addition the slight amount of extra engine wear you would sustain by using 5w-20 is small, however does exist.

Also agree with you 100% when a comparison is made between synthetic vs dino oil, however that is a completely different topic.

Comparing synthetic 5w20 (they all are - or at least a blend) and synthetic 5w30 is perhaps where we disagree. That being said a good discussion is what these boards are all about !)

 

I just put Mobil1 5W20 in this weekend fwiiw

 

I have no idea - but do not assume that it has to do with anything other than availability.

Check out those dyno results. Same engine, three different oils. More HP with 5w20. Better flow, less friction, better protection.

http://www.carcraft.com/techarticles/oil_tech/dyno_results.html

 

Better flow, less friction, better protection.

2 more average HP over the highest viscosity oil (for a +500hp engine)? I don't know how you can come to this conclusion from that article? Again, a flow gain (which it probably does flow better) doesn't necessarily correlate to better protection.

 

Both sides are putting up very good arguments. I'm guessing it is all splitting hairs.

1% better mileage, 1% better horse power, 1% better protection....

Not 1% better gas mileage and 30% more wear.

But who knows... Tell you what, the first person to have serious engine wear problems, let us know what oil you've been using.:smiley_thumbs_up:

 

Uh, no. 0.4% better horsepower (compared to 20W-50!) and no mention either way about protection.

The only thing mentioned up till now about protection is the Ford reference above...again, which does not directly call out 5W-30 (other than mentioning the .6 % increase in millage).

 

Response from Chrysler regarding if 5w30 would void the warrnaty.

"Thank you for contacting the Chrysler Customer Assistance Center
regarding your 2008 Jeep Patriot.

In response to your email regarding the Lifetime Warranty, we would like
to inform you that using the 5w30 oil in your vehicle may void the
Lifetime Warranty on your vehicle.

However, for more information on using the 5w30 oil, we suggest you to
contact your local authorized Jeep dealer since they are the best
resource for such information."

As usual the response is clear as mud.

 

It means if you did your own maintenance and your engine blows up, and they suspect you did something stupid, they are going to test your oil. If it does not meet the 5w20 spec you are screwed.

However, if they have records from a local Jeep dealer, and that dealer had done all the service using something other than 5w20, then they will honor it because it is the dealers liability. Basically it is not your fault if an authorised dealer puts something into your Jeep that is not recommended by the factory. You just went in for an oil change and the assumption (and weight of the law) is that a dealer knows what the factory recommends.

 

I did some checking too. 5W20 is unavailable in Europe. At least not through normal means. Matter of fact if you look at the Mobil 1 web site in the UK you will find that they sell a whole slew of different oils that are not found in the US. So it is really a case of different spec oils are sold overseas, and that TSB from Jeep UK is simply telling people to use the next best available thing which is 5w30.

Also found out that every motor oil sold in the US must go through EPA approval process. That is all that letter means.

Bob the oil guy and the machine lube mean nothing unless the test is using data from a GEMA engine.

The only real evidence so far comes from Ford and your owners manual. Doesn't that Ford letter explain how it protects better in a modern engine with tighter clearances?

 

I guess I don't see the arguement with this. I just checked my manual and it states that 5W20 is the oil they recommend. Period. (yes, API approved too)

There may be all kinds of different testing done (from BillyBob to racing engines, etc) but it all boils down to being safe for warranties sake. If they could prove you put in something other than what they said is approved, you might be in jeapardy of having to pay for work out-of-pocket. I can't afford that so (at least speaking for me) I'll stay with 5W20 until Jeep tells me otherwise.

You braver individuals who want to change viscosity or weight of your oils, feel free.

Gotta love choices, don't ya?:smiley_thumbs_up:

 

If it has a life time power train warranty then I'd use the recommended oil.

 

Do not think you are beating up on me at all. Your refusal to accept hard evidence from an automobile manufacturer because you feel "thinner" or "thicker" is vague is quite laudable. Your right, Bob the "Oil Guy" is a much better source of information. Enjoy your Jeep.

 

This post cracked me up a bit.

Do not knock BobistheOilGuy.com There are several Blackstone OUA reports that include real data. That site is the bible when it comes to any oil.


Prior to logging off this thread for good, lets summarize the data:


Mobil 1 Recommendation (What Mobil1/Exxon Suggests we should use)

Mobil1 UK Motor Oil (No 5w20 here, all the other weights are available in North America)

EPA Letter - CAFE (Shows North American car companies are up to something with the EPA when it comes to 5w20 - you decide what that is)

TSB Patriot Europe (5w30 is OK for Europe)

Jeep Patriot Parts Manual (Export and North American Engine/Emissions components are the same)

Machinery Lubrication Article (They hate 5w20)

BobistheOilGuy.com (Pretty big fish when it comes to oil info)

GEMA (Global Engine Manufacturing Alliance) (The World Engine used in the Patriot was developed outside North America)

American Petroleum Institute (Both 5w30 and 5w20 are approved lubricants, not sure Chrysler can void any warranties but you be the judge because Chrysler wont say)

Society of Automotive Engineers (Same as above)

VS

Car Craft Website (5w20 tested against oils other than 5w30)

Ford Fleet Rental Website (Ford likes 5w20)


And neither for or against that I can see:


EPA Used Oil Website (They created that 5w20 letter and do something with used oil)

 

Oil Viscosity

I wonder if this same discusion was being held at BoB's Burger Pit in the 80's about the virtues of using 5W30 vs 10W30 when 5W30 was first introduced???

 

Too funny.....

Homac has posted some good links. Something is damn fishy about the whole 5w20 thing.

The Europeans and Japanise make a heck of alot of vehicles, you would think if 5w20 is better they would be using it over there too.

Thinking about those burgers is making me hungry.

I wonder if this same discusion was being held at BoB's Burger Pit in the 80's about the virtues of using 5W30 vs 10W30 when 5W30 was first introduced???