winkosmosis
Explorer
I found an interesting article about oil viscosity
http://www.machinerylubrication.com/Read/518/motor-oils
http://www.machinerylubrication.com/Read/518/motor-oils
Oil weight for 4.0L-- 15W40 in Australia?
- Thread starter winkosmosis
- Start date
Stumpalump
Expedition Leader
That's a good read. When I called Mobil they told me 15w50 in any flat tappet cam engine like the 4.0 in any engine below the Arctic Circle.
winkosmosis
Explorer
I put in the 10W-40 and it seems quieter, with less of a high pitched fluttery sound. I don't know if it's for real or just placebo effect.
I just googled "10W-40 jeep oil analysis" to see if anyone has had one done with the thicker oil and found this thread http://www.jeepforum.com/forum/f9/anyone-use-10w-40-oil-414946/
A guy with a 2006 TJ in Mexico said:
Also found this http://www.wranglerforum.com/f5/oil-38303.html
A German says:
I just googled "10W-40 jeep oil analysis" to see if anyone has had one done with the thicker oil and found this thread http://www.jeepforum.com/forum/f9/anyone-use-10w-40-oil-414946/
A guy with a 2006 TJ in Mexico said:
Also found this http://www.wranglerforum.com/f5/oil-38303.html
A German says:
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PMA4x4
Adventurer
I've been running rotella T 15-40 for 3 yrs now. I live in Arizona so the heat thru most of the year is up there. Since I changed over I noticed the engine is more quite including the traditional 4.0 knock soun and oil pressure is more consistant. I had to pull the valve cover one time and this was about a a year or 3 oil changes after changing over. the inside of the cover was clean metal with a that golden brown stain to it.
If I know i am hitting more long term cold climates I will switch over to the 5-30 rotella
If I know i am hitting more long term cold climates I will switch over to the 5-30 rotella
86cj
Explorer
I just decided to switch my 2004 4.0L from Mobile 1 10w-30 to 5w-40 Mobile 1 Turbo Diesel oil due to it's 300 ppm higher ZDDP, it also meets SM gas engine requirements. I plan to run it year round and will post up if it does not work well, I have had no oil related issues to date and am being pro-active.
Nipple Twister
New member
After careful review.....
........"ramjet308": 5W-30 will be a useless change, there is NO oil which will have the needed viscosity at temps near freezing simply because there is no need. A properly running engine will warm to the operating temp for the oil which is also well above the need of 5W of multi-grade oil.
read on..................http://www.bobistheoilguy.com/cms/
........"ramjet308": 5W-30 will be a useless change, there is NO oil which will have the needed viscosity at temps near freezing simply because there is no need. A properly running engine will warm to the operating temp for the oil which is also well above the need of 5W of multi-grade oil.
read on..................http://www.bobistheoilguy.com/cms/
PMA4x4
Adventurer
Well I can say this. 20w-50 keeps a motor from starting compared to 5w-30 when its -30 below.
Maybe I am old school but the idea of hearing valve train noise on a cold morning because my oil is too thick just bugs the hell out of me. Or the fact that the oil is as thick as molasses and does not wish to flow. I am from a colder climate region and have seen too many trannys and motors destroyed by cold weather starts.
I have read up on Bob's site int he past. It is very intuitive.
It just comes down to how each owner wishes to maintain their vehicles.
Maybe I am old school but the idea of hearing valve train noise on a cold morning because my oil is too thick just bugs the hell out of me. Or the fact that the oil is as thick as molasses and does not wish to flow. I am from a colder climate region and have seen too many trannys and motors destroyed by cold weather starts.
I have read up on Bob's site int he past. It is very intuitive.
It just comes down to how each owner wishes to maintain their vehicles.
Cards81fan
Osage Hilltopper
I don't have an inline (only a pair of 3.7s here), but I will add that I believe super low weight oils (0w30 or 0w20 or 5w20) are more about squeezing power and fuel efficiency numbers out of a motor than necessarily protecting the life of the engine. Lower weight means thinner and thus less resistance (generally speaking - I know there is more science to it than that).
I like to run the thickest oil within reason as possible, particularly in warm weather (which we generally see in OK). Too thick of an oil may starve some engines for lubrication, but I am not exactly running a finicky or high-performance powertrain. In my Jeep and Dodge, it means 10w30 synthetic blend most of the time. In my old 4 banger Ranger, it was 10w40 Rotella if I could find it, and any name-brand 10w30 if I couldn't. If I were in a cooler climate, I certainly would consider a lower weight oil for the reasons outline in the post above. But these weights work for me in all but the very coldest Oklahoma winter mornings.
The FSM for my truck has this chart (which I believe a similar image appears in most vehicle's manuals these days):
Though they recommend the 5, I think it is primarily for efficiency reasons. In a warmer climate, the 10 is what I prefer. I see 100+ more often than below 0. But overall I still find it a good guide for the layperson.
As the earlier post mentioned, Mobil recommended a very heavy weight for the 4.0 compared to what Chrysler states. I personally err on the side of the person who made the product to be applied., but YMMV.
I like to run the thickest oil within reason as possible, particularly in warm weather (which we generally see in OK). Too thick of an oil may starve some engines for lubrication, but I am not exactly running a finicky or high-performance powertrain. In my Jeep and Dodge, it means 10w30 synthetic blend most of the time. In my old 4 banger Ranger, it was 10w40 Rotella if I could find it, and any name-brand 10w30 if I couldn't. If I were in a cooler climate, I certainly would consider a lower weight oil for the reasons outline in the post above. But these weights work for me in all but the very coldest Oklahoma winter mornings.
The FSM for my truck has this chart (which I believe a similar image appears in most vehicle's manuals these days):
Though they recommend the 5, I think it is primarily for efficiency reasons. In a warmer climate, the 10 is what I prefer. I see 100+ more often than below 0. But overall I still find it a good guide for the layperson.
As the earlier post mentioned, Mobil recommended a very heavy weight for the 4.0 compared to what Chrysler states. I personally err on the side of the person who made the product to be applied., but YMMV.
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Your wish shall be granted.....
I own a 1997 ZG Grand Cherokee Limited ( a ZG is an export build RHD ZJ built by Jeep's erstwhile partner Daimler Benz owned Steyr miltary plant in Graz, Austria.
I spend a lot of my time in Australia....the last 1 1/2 years in far north Queensland (FNQ) from Cairns to about 350-500 miles north, now I've driven 1/2 way across northern Australia and am around Darwin.
Here in Australia, the Owners Handbook specifies 15W as the MIN for minimum temps of about 0 degrees Celsius/32 deg Fahrenheit and suggests 30 or 40 as the upper value...... most 4.0L Jeep owners, dealers and Jeep specialists seem to use 20W/50 petroleum based oil because it's so common here......I've paid attention to Jeeps admonition and use a Shell Semi-Synthetic 15W/50 for High Mileage Engines (it's a heavier version of the same in a 10W/30, 10W/40, 15W/40 versions).
I've got nothing but praise for it (the oil.....and the Jeep 4.0L engine)....a few weeks ago the car ticked over the 240,000 kilometre point - that's about 150-160,000 miles.
I use a semi-synthetic because after the initial oil drain when new I put in Mobil 1 it leaked from every possible orifice!...The Dealer said that Jeep oil seals and gaskets just aren't meant for synthetic oils!....BTW I've used Mobil 1 in 1996 and 2003 Range Rovers witout any problems.
I own a 1997 ZG Grand Cherokee Limited ( a ZG is an export build RHD ZJ built by Jeep's erstwhile partner Daimler Benz owned Steyr miltary plant in Graz, Austria.
I spend a lot of my time in Australia....the last 1 1/2 years in far north Queensland (FNQ) from Cairns to about 350-500 miles north, now I've driven 1/2 way across northern Australia and am around Darwin.
Here in Australia, the Owners Handbook specifies 15W as the MIN for minimum temps of about 0 degrees Celsius/32 deg Fahrenheit and suggests 30 or 40 as the upper value...... most 4.0L Jeep owners, dealers and Jeep specialists seem to use 20W/50 petroleum based oil because it's so common here......I've paid attention to Jeeps admonition and use a Shell Semi-Synthetic 15W/50 for High Mileage Engines (it's a heavier version of the same in a 10W/30, 10W/40, 15W/40 versions).
I've got nothing but praise for it (the oil.....and the Jeep 4.0L engine)....a few weeks ago the car ticked over the 240,000 kilometre point - that's about 150-160,000 miles.
I use a semi-synthetic because after the initial oil drain when new I put in Mobil 1 it leaked from every possible orifice!...The Dealer said that Jeep oil seals and gaskets just aren't meant for synthetic oils!....BTW I've used Mobil 1 in 1996 and 2003 Range Rovers witout any problems.
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BTW.......That 15W/50 oil that I use is Shell Helix Synthetic Technology Oil for High Mileage Vehicles.....it comes in metallic dark blue plastic bottles, and because I use the larger/longer oil filter (#3001 or Z9 etc) I fill up with EXACTLY 6 litres (instead of 5.7) due to the bigger filter. I use Bosch premium oil filters with the anti-drainback valves.
Sorry to re-hash all of the above, but this wouldn't make much sense without it.
Quoting from my Jeep's Operating Information Handbook ( the Owners Handbook which came with the car when delivered new) :
Selecting Engine Oil:
Oil Quality- for maximum protection under ALL conditions use ONLY oils that conform to API Service Categories"SG" or "SG/CD" or "SH" or "SH/CD" or "SJ" or ABOVE for Gasoline Engines........
Engine Oil Viscosity It is recommended that SAE Grade 15W/40 engine oils that ALSO CONFORM to the API Service Categories specified above or an "Energy Conserving Oil #2 or CCMC- G4 be used.....SAE Grade 10W/30 European specification oil conforming to ALL of the the above Standards are also acceptable.
Low Viscosity Oils Low Viscosity oils make engine starting easier in extremely cold weather. Oils of the SAE 5W/30 or 10W/30 Grade numbers may be preferred when minimum ambient temperatues are consistently below -12 Deg Celsius/10 Degrees F NOTE : Low Viscosity oils must meet the API quality and standards above or have CCMC G5 designation!
That's Jeep's official standpoint on cars supplied new in Australia......
So, in summary for ambient temps above -12oC/10oF use 15W weight oil.....the upper figure/other half of the designation is stated as 40......but given that the first half is the reqired minimum, it is quite safe and OK to chose a multigrade oil that has a higher top weight in hot climates. So I've chosen to go with a 15W/50 because the temps don't drop below 24oC at night and EVERY day is over 30oC!.....I haven't gone to the ridiculous extreme of some people here (only a few!) and run 25W/70.....which is, in my opinion, too thick to circulate quickly on start-up and indeed during operation, as well as causing stress on oil pump and its drive and all other componentry. As shown above Jeep specifies 15W weight oil for ambient temps beween -12oC through to over 40oC. For the upper value 40 is specified by Jeep, but I've got a high mileage engine and I use it in fairly hot temps, so I've gone to 50 weight.
I hope this helps people.
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