My friend has one of these and has 6000 miles on the oil that is in it right now. We are about to change it and I saw that Mobil 1 0w40 and maybe either a wix or k&n filter would do his motor well. Only concern I have is doing a long interval like 5k or 6k miles on that oil and filter right after a 6k mile interval of the mystery brand put in my carmax... is it ok to go ahead with the slightly long interval or would a basic flush, probably wont bother getting into autorx and all that with it, do it some good?
1996 4.0 cherokee oil question
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If you upgrade him to Mobil 1 Truck and SUV 5w-40 ..he's probably good for 10k-15k or a year. That 0w-40 allegedly has a tendancy to turn into a 30 weight ..or so some report.
..but ..maybe a shortened first OCI on whatever M1 you decide on would be in order ..but I still wouldn't dump any synthetic before 5-6k/6months.
..but ..maybe a shortened first OCI on whatever M1 you decide on would be in order ..but I still wouldn't dump any synthetic before 5-6k/6months.
I have a 1987 Jeep Cherokee with the same engine. When I decided to go with full synthetic oil, I added it a quart at a time with each oil change. For example:
The engine takes 6 quarts with a new oil filter.
I was using Mobil conventional 10W30 Oil. I decided to go with Mobil 1 10W30. So during one of my oil changes, I put in 5 quarts of the Mobil conventional, and 1 quart of the Mobil 1. Then after 3,000 miles, I changed the oil and filter, adding 4 quarts of Mobil 10W30 conventional, and 2 quarts of Mobil 1; at each oil change I would substitute 1 quart of conventional for one quart of synthetic, and so forth until I was running 6 quarts of the Mobil 1.
It took a while, but the reason I did it is that I was told that if you were to change 6 quarts of conventional, and replace it with 6 quarts of synthetic all at once, the cleaning power of the synthetic might sweep up "engine gunk" into the filter and clog it. By switching over slowly, I was able to help gradually clean my engine and protect it better (in my opinion) with the Mobil 1 10W30 synthetic oil. My way might have been too cautious, but it worked.
The amount of "engine gunk" in your friend's Jeep would depend on mileage and how frequently the oil was changed before he bought it.
I hope this information does you, and your friend, some good.
The engine takes 6 quarts with a new oil filter.
I was using Mobil conventional 10W30 Oil. I decided to go with Mobil 1 10W30. So during one of my oil changes, I put in 5 quarts of the Mobil conventional, and 1 quart of the Mobil 1. Then after 3,000 miles, I changed the oil and filter, adding 4 quarts of Mobil 10W30 conventional, and 2 quarts of Mobil 1; at each oil change I would substitute 1 quart of conventional for one quart of synthetic, and so forth until I was running 6 quarts of the Mobil 1.
It took a while, but the reason I did it is that I was told that if you were to change 6 quarts of conventional, and replace it with 6 quarts of synthetic all at once, the cleaning power of the synthetic might sweep up "engine gunk" into the filter and clog it. By switching over slowly, I was able to help gradually clean my engine and protect it better (in my opinion) with the Mobil 1 10W30 synthetic oil. My way might have been too cautious, but it worked.
The amount of "engine gunk" in your friend's Jeep would depend on mileage and how frequently the oil was changed before he bought it.
I hope this information does you, and your friend, some good.
Good question. I have a 4.0 Jeep engine and they will run forever. I recently changed my wife's car over to Mobil 1 after a steady diet of conventional oil. The Mobil 1 really darkened quickly as it cleaned out 100K miles worth of conventional leftovers. I ran it for 3K miles before changing it and I believe that I left it in the engine too long. It was obvious that the oil was full of removed material.
Mobil (on their website) used to recommend a couple of short OCIs (2500 and 3500) when first switching from conventional to M1 before extending drains with Mobil 1. Their reasoning was that the M1 would clean your engine of leftover conventional and become saturated. I also remember reading that M1 OW40 has the most cleaning power of all the M1 products (prior to the EP versions)....so it could really become saturated quickly.
I think that the idea from adreeed24 was a good one....allowing gradual cleaning by the synthetic. You could also just run a couple of short OCIs with the M1. It cost a little more, but it might be the best choice.
Mobil (on their website) used to recommend a couple of short OCIs (2500 and 3500) when first switching from conventional to M1 before extending drains with Mobil 1. Their reasoning was that the M1 would clean your engine of leftover conventional and become saturated. I also remember reading that M1 OW40 has the most cleaning power of all the M1 products (prior to the EP versions)....so it could really become saturated quickly.
I think that the idea from adreeed24 was a good one....allowing gradual cleaning by the synthetic. You could also just run a couple of short OCIs with the M1. It cost a little more, but it might be the best choice.
Not the cheapest why to clean the motor out, but effective would be to do the Auto RX deal. This would ensure the motor was ready for the synthetic oil.
I don't think you need a synthetic in the 4.0.
I did a double ARX thing at 100K on my Cherokee, it's always run dino, Castrol GTX for about 80K or so, then Chevron Supreme. All 10W30. It runs like it was brand new. I did a used oil analysis recently and the numbers were as good or better than any I've seen.
I did a double ARX thing at 100K on my Cherokee, it's always run dino, Castrol GTX for about 80K or so, then Chevron Supreme. All 10W30. It runs like it was brand new. I did a used oil analysis recently and the numbers were as good or better than any I've seen.
I sold my 95 Jeep 4.0L at 156,000 miles running great and no leaks using Mobil 1 10w30 and Purolator oil filter. I switched to Mobil 1 at the first oil change at 2,500 miles. The jeep is now in my son-in-laws hands and going strong. I used a 5-6,000 mile oil change interval
I change my 97 4.0's oil/filter every 3k. I wouldn't go past 5k max but that's my opinion. These engines are NOT like most modern engines. The 4.0 has big bearings, "loose" clearances, runs hot and is a old design based on a ancient design and should be treated like a old engine...i.e stay with conservative oil/filter changes.
The best widely available synthetic lube to run in these is Mobil Delvac 1, 5w-40, period. All the oil analysis data I've seen over the past several years supports this.
I also recommend the 5w-40/10w-40 Amsoil lubes for this same low rpm application.
TS
I also recommend the 5w-40/10w-40 Amsoil lubes for this same low rpm application.
TS
I have very good luck with mine with 10K oil changes. They are all engines internal combustion with basically the same layout. As far as I am considered they are very clean running powerful motors. Large bearings are good too. A heavy 10W30 seems to fit the bill very well as does light 10W40’s, not because the motors are bad in any way, just because it works.
Shoot even the 1950 flathead Ford I’m currently building is as modern as anything else on the inside. Heck just look at the new Mod motors if you need to find something that has taken a few giant steps backwards.
The bigger the bearing, the harder it is on oil. The bigger bearings have greater bearing speed and that means more friction and less oil life and even shorter bearing life compared to smaller bearings. That's out of the latest issue of Car Craft.
By modern, I mean bearing and internal clearances. The Jeep 4.0 is nowhere near as tight as say a new Hemi or even a BMW inline. It's a great engine and I wish Jeep wasn't going to get rid of it.
[ March 31, 2005, 03:58 AM: Message edited by: 99 ]
By modern, I mean bearing and internal clearances. The Jeep 4.0 is nowhere near as tight as say a new Hemi or even a BMW inline. It's a great engine and I wish Jeep wasn't going to get rid of it.
[ March 31, 2005, 03:58 AM: Message edited by: 99 ]
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I wonder about this statement a little. A bigger bearing may have more of a surface area to produce friction ..but distributes the load over a larger "force/load bearing surface"...so I think this would be reduced to another component of the lubrication system since, assuming all other things being equal (stroke for thrust duration, hp density, etc.), the larger bearing would have an easier time. This is just my level of reasoning at work here, folks (visions of wide track "low ground pressure" tracked vehicles in motion on soft surfaces)
Also ..the statement isn't indexed for diameter of bearing or the width. A wide small journal bearing would "slower" than a narrow large journal bearing .. Then what of a large and wide bearing
Can you add a little "filler" in here from the article??
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