Lets Talk Motor Oil

[Hopkins]

Alright guys I need to learn a little more about the subject. I have done some reading online, but answers are vague and non-specific at best.:bang:

With that said, what is the best Grade/Weight of oil to run for the 4.0L?

I run 10W-40 and was under the impression that a thinker/heaver oil was better for an older engine with high mileage, but some information I have gone over may suggest otherwise.

In a nutshell the theory is that the thicker/heavier oil is too thick at start-up and cannot lubricate the engine until operating temp is met, therefore causing excessive engine wear until the engine warms up and the oil thins out.

If anyone cares to read more on this subject here is the link:www.bobistheoilguy.com/motor-oil-101/

I would really like some real world opinions from my fellow XJers...:bacondance:

[Firemanray]

One of the update schools I went to several years ago for Volvo Penta Marine engines had an in depth presentation about motor oils. My old school opinion was that oil thins as it heats, however I learned that the engineered multi viscosity oils on the market today actually become a heavier weight when heat is added.

As far as what's best to run in high mileage engines, I'm not sure. I personally run Mobile 1 full synthetic in all my gasoline engines and Shell Rotella full synthetic in my diesels.

The Xj gets 10w40 and everything else gets manufacturer suggested grade for my climate. (2012 Chevy Traverse uses 5w30, seems light to me?!?)

I'm not sure I did anything but muddy the waters for you but that is my opinion of the subject.:D

[XJ Wheeler]

One of the update schools I went to several years ago for Volvo Penta Marine engines had an in depth presentation about motor oils. My old school opinion was that oil thins as it heats, however I learned that the engineered multi viscosity oils on the market today actually become a heavier weight when heat is added.

As far as what's best to run in high mileage engines, I'm not sure. I personally run Mobile 1 full synthetic in all my gasoline engines and Shell Rotella full synthetic in my diesels.

The Xj gets 10w40 and everything else gets manufacturer suggested grade for my climate. (2012 Chevy Traverse uses 5w30, seems light to me?!?)

I'm not sure I did anything but muddy the waters for you but that is my opinion of the subject.:D

I question the first part of that about it thickening with heat because, when changing the oil you are suppose to get the engine up to temp then drain it because its thinner.

Sent via messenger pigeon - i talk, he types.

[XJ Wheeler]

I use what my xj seems to like, weight wise. 10w-30 for summer use, and 5w-30 for winter. Oil pressure seems good with these. Made the switch to 5w-30 in the winter because i was getting a bad knock/tap when it was about 30° or less out. No problem since i switched.

Oil type and brand is due to experience. Castrol GTX because we've ran that in all our engines and all have high mileage still going strong... One was sold at 316k miles and ran it front new.

Sent via messenger pigeon - i talk, he types.

[Brasscatz]

I typically stick with 10w-30 as well. I did my first oil change on my 2012 Civic the other day.... it calls for 0w-20.... not cheap oil.

[drakan1908]

I run Vavoline 10w30 year round in my Grand and the wife's Forester.

Sent from my XT907 using Tapatalk

[abebehrmann]

I typically stick with 10w-30 as well. I did my first oil change on my 2012 Civic the other day.... it calls for 0w-20.... not cheap oil.

I hate to recommend shopping there, but Walmart has the best prices for synthetic oil, including 0w20. I picked up a 5qt jug of Mobil1 synthetic 0w20 for $25.

Damn, that is a LONG article. I got through 5 chapters before calling it a night. I feel like it makes sense in theory but I'm not sure if his logic holds up to real world use. I use Mobil1 10w30 synthetic with the larger size oil filter.

[drakan1908]

I think Bob the oil guy is over thinking. I believe a good quality oil and a good filter, changed on a regular basis is the key. A 5w30 or 10w30 oil would meet most vehicle requirements

Sent from my XT907 using Tapatalk

[Brasscatz]

I hate to recommend shopping there, but Walmart has the best prices for synthetic oil, including 0w20. I picked up a 5qt jug of Mobil1 synthetic 0w20 for $25.

Damn, that is a LONG article. I got through 5 chapters before calling it a night. I feel like it makes sense in theory but I'm not sure if his logic holds up to real world use. I use Mobil1 10w30 synthetic with the larger size oil filter.

Thanks, I got the Mobile 1 stuff and filter for about $50 at advanced auto. I'm going to Wal-Mart next time!

Sent from my Samsung Galaxy S4 because my microwave couldn't do it

[4.3LXJ]

I buy my synthetic oil at Walmart too. Great prices. Now to throw a wrench into the works, I use Valvoline 20W50 racing oil. High mineral content, but burns clean on spark plugs. It is designed for hard use, and face it when we hit the trails this is beyond grocery getting. It will also take more heat without breaking down additives, which can be an issue to us. If you overheat, theoretically you should change your oil because of that

[bad luck]

I use Rotella T synthetic in everything, gas and diesel. Without any additives such as Lucas. I'm getting close to 2 million miles on my truck engine now, with a rebuild at 1,300,000 miles. When I say truck engine I'm not talking about my jeep, it is a 12.7 liter dd series 60.

[drakan1908]

I buy my synthetic oil at Walmart too. Great prices. Now to throw a wrench into the works, I use Valvoline 20W50 racing oil. High mineral content, but burns clean on spark plugs. It is designed for hard use, and face it when we hit the trails this is beyond grocery getting. It will also take more heat without breaking down additives, which can be an issue to us. If you overheat, theoretically you should change your oil because of that

When I had my VW I ran 20w50 in it because it could take the heat. Only weight that kept the oil light from flickering on a warm day.

Sent from my XT907 using Tapatalk

[Brasscatz]

I buy my synthetic oil at Walmart too. Great prices. Now to throw a wrench into the works, I use Valvoline 20W50 racing oil. High mineral content, but burns clean on spark plugs. It is designed for hard use, and face it when we hit the trails this is beyond grocery getting. It will also take more heat without breaking down additives, which can be an issue to us. If you overheat, theoretically you should change your oil because of that

Would you suggest using that in the 4.0, or is it more suitable for your 4.3?

Sent from my Samsung Galaxy S4 because my microwave couldn't do it

[4.3LXJ]

Yes I would suggest using it in a 4.0 that is known to run hot anyway. The 4.3 is a cooler running engine than a 4.0 by far. I never exceed 195° except in extreme situations where it goes to 210° for a brief period. I also use it my onboard air system which can get very hot also and have had no lubrication problems in a compressor that is not designed to pump air

[Hopkins]

It's good to hear everyone's responses and stir up some technical discussion.

Right now I am having a problem with my Jeep taking a lot to start. I am having to hold the ignition in the start position for a full 3 to 4 seconds until the engine actually fires. It seems to fire up quicker in warmer weather. I have only had the XJ for about 8 weeks now and I bought it with 10w-40 Mobil 1 Synthetic in it. After doing on this reading on oil I think it is worth a shot to swap the oil to 5w-20 synthetic and see what kind of difference that makes on the labored engine starting. Right now the engine runs cold, between 190 and 200, so I am not worried about overheating. If I start to see high temps then I will step it back up a grade/weight. I'll make sure to report my findings as I think this will be a cool expiramemt to see just how much oil affects(effects?) start-up.

[Carves]

Little chart from the XJ FSM ......

http://i1143.photobucket.com/albums/n629/carves-oz/Vehicle%20Bits/Engine/OilRangeChart-FSM_zps904bdcde.jpg


If I apply it literally ... neither of the factory spec oils weights appear to be much good to me.

I rarely get out of bed - if its only, 30*f, in the morning ... let alone, bother starting the car .. :D

This chart is a little better, as a general, oil use guide ... IMHO

http://www.onallcylinders.com/wp-content/uploads/2012/05/SAEViscosity.gif


FWIW ... dont just accept forum stories and sale marketing hype about whats the best oil,

... look at, how and where, you drive your vehicle, and use viscosities to suit.

Its really no different to tyre pressures, tyre tread patterns, coolant ratios and other stuff ... Use whats right for the job .. ;);)

I'm partial to using 15w/40 ...but like 4.3LXJ - I'm quite happy running 20w/50.

[JeepOnly]

Let me start by saying everyone has their opinions and ideas as to what oil to use and no one is wrong. I thought my two experiences may help in showing a heaver oil isn't really a problem. The one thing I do is always and I mean always watch my oil gauge when I start the engine it usually takes less than 2 seconds to get up to pressure.

I had a AMC Gremlin it had the 4.0 IL6 engine. I used Amalie 10w-40. Once I had to drive it 4 miles without water in the radiator and it never hurt the engine or burned oil, I sold it 2 years later. I'm now the original owner of a 1988 and 1996 Jeep Cherokee 4.0 IL6. I always used Castrol GTX 20w-50, same as the Gremlin I had to drive the 1988 Jeep 6 miles after the heat control valve gave out. It had just over 298000 miles at the time, it's now 150 miles short of 300000 miles and is driven daily to work. It doesn't burn any oil and this past year I had to replace the rear engine oil seal so I changed the oil pump also. My wife has a 1996 Jeep has around 110000 miles and I use the same oil in it. Due to these two experiences I won't use any thing else but the Castrol GTX 20w-50.

[4.3LXJ]

I would like to make a few more comments on this subject. When manufacturers recommend oil, there are two main things they take into account. One is how tight the engine is when made. The tighter the engine, the lower the weight of oil can be used because the bearing and piston tolerances are close. Modern engines are being made tighter and tighter. The second consideration is CAFE standards. Lighter oil means less work for the oil pump to put out in those tighter tolerances. But as an engine wears, those tolerances increase. As they do, a heavier oil is needed to prevent damage to the bearings. If your pressure is low, it means you need a heavier oil. Also if you live in hot climates, heavier oil is needed. And lastly, these 4.0 engines run hot anyway, so a heavier oil will keep them running longer

[nickyg]

Growing up on the farm we had 15w40 delivered in a drum. We used it in everything from tractors to mom's Pontiac wagon. I don't know if that was good or not but nothing blew up.

[XJ Wheeler]

I would like to make a few more comments on this subject. When manufacturers recommend oil, there are two main things they take into account. One is how tight the engine is when made. The tighter the engine, the lower the weight of oil can be used because the bearing and piston tolerances are close. Modern engines are being made tighter and tighter. The second consideration is CAFE standards. Lighter oil means less work for the oil pump to put out in those tighter tolerances. But as an engine wears, those tolerances increase. As they do, a heavier oil is needed to prevent damage to the bearings. If your pressure is low, it means you need a heavier oil. Also if you live in hot climates, heavier oil is needed. And lastly, these 4.0 engines run hot anyway, so a heavier oil will keep them running longer

Totally agree. And i know this from experience. Our '94 chevy 1500 runs 20w-50 for just that reason. That 350 is getting old and less tight inside. Has a bit of a smoke if its not cranked regularly.

Sent via messenger pigeon - i talk, he types.

[JamesPT]

In my abused 1.9Td, I'm running Castrol Edge 5W40 Diesel oil, best of both worlds. 5W for the starting, and 40 when hot. Theres also a 10W60 here.

[ETXXJ89]

I normally run full synthetic 10w-30 but after reading this I might go to either SAE-30 according to the chart or as quite a few said 20w-50. we all know how hot it can get in the summer down here in Texas.

[ArmyGuy45]

So that means higher mileage oil is thicker even through by both say 5w-30?

[4.3LXJ]

Yes, due to engine wear. It should be heavy enough to maintain good oil pressure

[sbspence]

Www.Bobistheoilguy.com more info than you will ever need about oil. :)


Sent from my iPhone using Tapatalk

[Metlic53]

I run castrol 10w-40. I think i'll try the valvoline 20w-50 in the offroad jeep and see how it does. Gotta put 0w-30 castrol european formula in my bimmer. 10 bucks a quart!

[mattyblazer]

jumping in here late in the game but if you search on Advanceautoparts.com and click the oil change deals tab http://shop.advanceautoparts.com/o/motor-oil
they always have a full synthetic for $19 with a filter
Blends are a scam, they can put a few ounces in and call it a blend

[mattyblazer]

Anyway, got to Advance Auto, they didn't have ant 10 30, so I asked, and they gave me a different synthetic they did have with a Fram extra guard for the same price

[cpttuna]

I went to my local NAPA store this afternoon. I picked out regular 10W-30(which is a popular blend) and started pricing. QS was $5.29, PEN was $5.99, VAL was $5.69, CAST was $5.69 and NAPA was$3.99. Since there was nothing special written on one bottle that was not written on another, from that standpoint it comes down to price unless for some reason your stuck on a certain brand.(You could also go to the local Wall Mart and for $17.00 get your oil changed and a Fram oil filter to boot. I will say that I use one of these brands but the day before I bought it on sale at $2.49 a bottle. Since I have not seen anything in print showing one brand is better than another, I believe it comes down to what works best for the individual at the price they are willing to pay.

[OneArmArrowSlinger]

I've never been a big fan of multi weights. Maybe it was the way I was raised but my dad & grandpa don't either. We've always ran 40w in the summer & 30w in the winter and never had a problem with noise on start up, its always held good pressure, & ran cool. Also, since its kind of a family rule that we never buy new cars, we've never seen a problem in high mileage vehicles. Its just never made any sense to me how an oil can be two different viscosities or how it could thicken as it warms. Maybe I'm wrong but since its always been good for us, I'm sticking with it. Just my .02.

[mattyblazer]

I like to think that the synthetics last longer in theory, they seem to stay gold in color longer, and I notice a slight gain in mileage. It's been a while since they were introduced so I'm hoping that the statistics are correct, on the other side of the coin times are tough right now so if I was not able to score synthetic and a filter for $20 I wouldn't bother with it

[Infidel Edition]

I run valvoline high mileage synthetic blend 10w40 summer 5w30 winter.
the 'high mileage' rating (according to that guy) has some extra additives related to older engine wear patterns or something.
only time I really push heavyer oil is when I have a slight leak of maybe some smoke out the exhaust... as the thicker weight won't seep by the rings as (or leak) as easily as thin 0 weight oil.
as long as you change our oil regularly... you don't really need a full syn.
the syn blend (yup @ Walmart) gives you a more consistent weight through the heat ranges.
thus a hotter running engine like a 4.0 running syn 10w40 ... the oil will behave more like 10w40 at temp vs. straight 10w40 will be more like a 5w20 at 210°.
this is according to a friend that builds off road racing trucks.

...in the end, I just 'feel better' with the oil I use.

[Paddletrucker]

I've got to where I run Mobil DelVac 15w40 in everything from my Jeep to my wife's car to my Cat powered semi. My Cat is sitting at 1.9 million miles without an overhaul. It's most likely coming soon. Lol. Running good though. I bought it at 450,000 miles and began running the DelVac on the recommendation of the shop that does my engine work. I've tried the synthetics in everything but the semi and liked them but the DelVac 15w40 is the best price and I don't have to buy different oils for all 6 vehicles. My Jeep has 240,000 on it now and it likes the DelVac better than anything I've poured into it, including the 20w50 AmsOil racing oil, which was A LOT more expensive

Sent from my SAMSUNG-SM-N900A using Tapatalk

[XJ Wheeler]

I've got to where I run Mobil DelVac 15w40 in everything from my Jeep to my wife's car to my Cat powered semi. My Cat is sitting at 1.9 million miles without an overhaul. It's most likely coming soon. Lol. Running good though. I bought it at 450,000 miles and began running the DelVac on the recommendation of the shop that does my engine work. I've tried the synthetics in everything but the semi and liked them but the DelVac 15w40 is the best price and I don't have to buy different oils for all 6 vehicles. My Jeep has 240,000 on it now and it likes the DelVac better than anything I've poured into it, including the 20w50 AmsOil racing oil, which was A LOT more expensive

Sent from my SAMSUNG-SM-N900A using Tapatalk

I wish light duty trucks lasted that long!

Sent via messenger pigeon - i talk, he types.

[mattyblazer]

I have heard that there is really something to the high mileage blends (my kid is Air Force) I had not considered that with regards to blends.

One thing I did notice was that I get valve noise when I use synthetic at idle, anyone else get that?
:confused:

[Infidel Edition]

I have heard that there is really something to the high mileage blends (my kid is Air Force) I had not considered that with regards to blends.

One thing I did notice was that I get valve noise when I use synthetic at idle, anyone else get that?
:confused:

Have you tried running a can of SeaFoam through there?

[mattyblazer]

Have you tried running a can of SeaFoam through there?

I ran it through the vacuum lines with it, you mean pour it in with the old oil before changing?

[OneArmArrowSlinger]

I ran it through the vacuum lines with it, you mean pour it in with the old oil before changing?

I was always told to put it in with the new oil when changing. I hope I wasn't told wrong but if I was, no bad side effects yet!:bacondance:

[Infidel Edition]

I was always told to put it in with the new oil when changing. I hope I wasn't told wrong but if I was, no bad side effects yet!:bacondance:

You did what in your vacuum lines?

SeaFoam goes in the fresh new oil. Simply to reduce buildup and clean the innards.
* There's also a "don't drive after pouring in" oil cleaner that you run the engine for 5 minutes to circulate ... then change the oil to get the supper crud out. But I've never tried it.

If you've run SeaFoam and still have that knocking ~ I'd do a quick search on the forums or post a new thread asking for thoughts / input. You'll get a ton of great info and advice.

Depending on mileage and such, the 4.0 can develop a knocking ~ almost becoming a diesel sounding engine ~ due to various things like sticky lifters or worn valve springs.
BUT, I'M A BACKYARD MECHANIC ... there are other more mechanically inclined professional types that can better field that question.

[OneArmArrowSlinger]

You did what in your vacuum lines?

SeaFoam goes in the fresh new oil. Simply to reduce buildup and clean the innards.
* There's also a "don't drive after pouring in" oil cleaner that you run the engine for 5 minutes to circulate ... then change the oil to get the supper crud out. But I've never tried it.

If you've run SeaFoam and still have that knocking ~ I'd do a quick search on the forums or post a new thread asking for thoughts / input. You'll get a ton of great info and advice.

Depending on mileage and such, the 4.0 can develop a knocking ~ almost becoming a diesel sounding engine ~ due to various things like sticky lifters or worn valve springs.
BUT, I'M A BACKYARD MECHANIC ... there are other more mechanically inclined professional types that can better field that question.

Sorry, I didn't mean in my vacuum lines, I ment I put it in with my new oil.

[Infidel Edition]

Not sure what it'd do to vacuum lines...
but probably not the best way to use.:rolleye0012:

[4.3LXJ]

To clear some Seafoam myths, it is a super detergent that if in a combustion chamber expands enough to dislodge carbon buildup on the tops of pistons and cylinder heads. The instructions say to poor it in the intake. Most people pull the brake booster hose and poor it in enough to get a "white smoke" out the tail pipe. But, what can happen is there is enough of that smoke to foul the O2 sensor and then you need to change it because it gives you a CEL. A better way to use it is to poor a bottle in a 1/4 tank of gas and go for a drive. Simple, no drama. It will remove all the carbon that way too. No drama either. O2 sensor will be fine. It probably is not a good idea to use it in oil for longer than a few minutes. It has no lubrication properties

[mattyblazer]

http://seafoam.com/ (http://seafoamsales.com/vacuum-line-method-with-sea-foam/)
The manufacturer says its ok in the crank case oil, and vacuum lines

[Paddletrucker]

I wish light duty trucks lasted that long!

Sent via messenger pigeon - i talk, he types.

They probably could. I've got a buddy who's got a dodge diesel and a Ford diesel pickup that he uses to haul cars on three car hauling trailers. They both have over 500,000 on them. With my large Cat, the overheads are run every 150,000 miles or so. In other words, the valves and injectors are adjusted. Also, it never runs consistently over 1450 rpms or so. That may play a role, I don't know. Also, I have a pretty aggressive maintenence program and oil and fuel samples are taken and analyzed every other oil change, so i can see problems coming amd address them before anything bad happens. With proper maintenance, I'm not so sure you couldn't go a million on a diesel powered pickup. If...if...The body and chassis would hold up.



Sent from my SAMSUNG-SM-N900A using Tapatalk

[XJ Wheeler]

They probably could. I've got a buddy who's got a dodge diesel and a Ford diesel pickup that he uses to haul cars on three car hauling trailers. They both have over 500,000 on them. With my large Cat, the overheads are run every 150,000 miles or so. In other words, the valves and injectors are adjusted. Also, it never runs consistently over 1450 rpms or so. That may play a role, I don't know. Also, I have a pretty aggressive maintenence program and oil and fuel samples are taken and analyzed every other oil change, so i can see problems coming amd address them before anything bad happens. With proper maintenance, I'm not so sure you couldn't go a million on a diesel powered pickup. If...if...The body and chassis would hold up.



Sent from my SAMSUNG-SM-N900A using Tapatalk

It may be possible, with the right diesel, but pretty much unprecedented. I've seen trucks with 600-700k (one was a gas 3/4ton chevy with 700k) but I assume its possible to make it the rest, just not typical like big rigs. I mean, its nothing for a detriot to do a million, and these days 400k seems rare in 1-tons.

[OldFaurt]

Alright guys I need to learn a little more about the subject. I have done some reading online, but answers are vague and non-specific at best.:bang:

With that said, what is the best Grade/Weight of oil to run for the 4.0L?

I run 10W-40 and was under the impression that a thinker/heaver oil was better for an older engine with high mileage, but some information I have gone over may suggest otherwise.

In a nutshell the theory is that the thicker/heavier oil is too thick at start-up and cannot lubricate the engine until operating temp is met, therefore causing excessive engine wear until the engine warms up and the oil thins out.

If anyone cares to read more on this subject here is the link:www.bobistheoilguy.com/motor-oil-101/

I would really like some real world opinions from my fellow XJers...:bacondance:

As an Old Fart, I look at oil like this,

A good quality oil is degraded over time by:
1. Blow by gasses to include, unburnt gas, carbon & oil from the cylinder walls that gets burnt.
2. Water that condensates in the engine from heat / cold transitions
3. Oxidization
4. Metallic components of wear.

The filter is able to handle "Most" of the solid particulates in the oil but has little effect on the acids, oxides that form from the above contamination.

Those chemical contaminates modify the ability of the oil to form a strong surface tension that the metal parts in your engine ride upon.
For instance, on a freshly rebuilt engine that has been properly broken in, you can take an ohm meter and measure the resistance between the Crankshaft and the block and often find a rather high resistance.
There is little to no metal to metal contact!

Modern engines use tolerances measured in the 2-4 thousands of an inch!

As those impurities start changing the composition of the oil, surface tension starts to break down and this has the effect of letting more metal to metal contact happen!

This is where wear comes from!

So Even that hot spit filter and the best Synthetic oil can not guarantee low wear.
You have to minimize that accumulation of acid, and crap to avoid wear!
So, on most levels, higher frequency of changes with cheaper oil can be as effective as fewer changes with "Fancy Pants" oil.

So, if you do a lot of short trips, under 15 minutes per drive, you might do better by more often changes with good oil and the oil filter every 2nd or even third time! The reason is the engine does not get hot enough long enough to evaporate the water condensation that mixes with the other crap to form acids.
Longer trips, 1/2 hour or more on freeway? Plenty of heat to bake out the water, less surging power dumping raw fuel past the rings, etc,
Might be Better running Synthetics changed less often but filter change every time!

Truck drivers often send in a sample of their oil for analysis to determine change rates! Wonder what they know?

Me, I drive an hour and a half each way, every day!
For me a nice royal purple full syn with a high quality Oil filter is my preference as I do over 2500 miles a month, just on commute
and change oil, filter ever other month!

(My wife's 2002 Honda has nearly 200,000 with no build up of sludge, just clean oily metal and runs like a top!)

So, how does that sound?:smiley-gen165:

[Rocco83]

I have used Rotella T5 10w30 in all the Jeeps I've ever owned and have never had a problem. I also use oversize filters and only change every 7500 miles. Wix 51515 filter for the 4.0L if you want to run the oversize. All my buddies who run a Jeeps use the Rotella T5 as well.

Also might as well mention I buy it at WalMart cheaper than I can find it anywhere else.

[tsd123]

What about zinc or zddp in the oil? I used to run rotella 15-40 in my flat tappet muscle cars but, I heard they removed the zinc that protects the flat tappet cams. The reason they have been removing it is, all the newer cars are roller or non push rod engines. Has anyone had a problem with cam lobes wiping on here? The only thing I run now is valvoline vr1, because it states it has zinc in it.

[4.3LXJ]

What about zinc or zddp in the oil? I used to run rotella 15-40 in my flat tappet muscle cars but, I heard they removed the zinc that protects the flat tappet cams. The reason they have been removing it is, all the newer cars are roller or non push rod engines. Has anyone had a problem with cam lobes wiping on here? The only thing I run now is valvoline vr1, because it states it has zinc in it.

Valvoline is the way to go for flat tappet engines

[whitdog54]

10w-30, usually the best oil change deal for a name brand. lots of highway, but I do it every 7500miles give or take. Put on almost 30k, so far so good minus some emission/electrical gremlins.

[muskie]

Muskie here You want more info on best oil for our xj rigs Go to Cherokeeforum.com. There you'll find a post called "Rotella: The world's first ever combined hair oil,foot ointment,and salad dressing" Why it's listed that way I don't know ,but it is a 15 page post, worth every bit. I've tried it in my xj ,and at-20 I had no problems this past winter.I used the 5w-40.Don't let the fact that it is a deisel engine oil scare you. My xj is running quieter than it did with Castrol high mileage synthetic. Do yourself a favor and read the whole thing. The charts at the end say a lot to prove-out the post

[cpttuna]

I have read a lot about which oil and which filter and when to change. I have not heard one comment about something like: well, I usually change at 3000 miles but if I'm a quart low at 2000, I go ahead an just change it early or I usually just add a quart then if low. Do any of you people just add a clean quart to the dirty oil or do I assume no of you people use any oil between changes?

[mattyblazer]

I have read a lot about which oil and which filter and when to change. I have not heard one comment about something like: well, I usually change at 3000 miles but if I'm a quart low at 2000, I go ahead an just change it early or I usually just add a quart then if low. Do any of you people just add a clean quart to the dirty oil or do I assume no of you people use any oil between changes?

I just added a quart at 2000 miles, full synthetic killed me to do it.

[Hopkins]

If I check the fluids and oil is low I will add a clean quart, but I will still maintain my regular oil change schedule of every 3k. I do not extent that particular oil life because I added a clean quart.

[Infidel Edition]

If I check the fluids and oil is low I will add a clean quart, but I will still maintain my regular oil change schedule of every 3k. I do not extent that particular oil life because I added a clean quart.

In theory ~ high mileage oil's have "additives" in them....
so by adding a clean quart, you would (minimally at best) extend the oil life.
The problem is you're doing nothing for the filter ~ or other junk that's in the oil.

Thus, I still change it when it's due

[dagod16]

No matter how many miles you have on your jeep, 10w30 works fine. and 5w30 works fine as well. 5 Qts at walmart for $15, and I change it every 5K on the nose!

If you want to use synthetic oil, is fine in a brand new car and you new car is used to this!. If you have high miles like me 207k and you have been using regular 10w30 oil for the entire time and switch over to synthetic you will develop drips and leaks because the seals on your engine have dried up over the last 14 years and the thinner oil will leak out more. Switching back to your regular oil will fix this problem. Also once in a while I use marvels mystery oil, or at205. Just add a little bit into each oil change or once in a while. It lubricates the engine and all the seals. I have like one drip once a week or once every other week.

Also did anyone notice that walmart sells a metal tray to put under your vehicle to catch the drips, instead of cardboard.

You can switch back and forth from synthetic back to regular 10w30 oil without issues.

Keep in mind synthetic can last like 10,000 miles maybe even 15,000 miles. but it does cost more.

[Rocco83]

I prefer semi-synthetic, but everyone has their likes, dislikes, and preferences. I've just never had problems with semi-synthetic and I'm gonna stick to it. 10w30 has always been fine for the weather here in Ohio.

[mattyblazer]

No matter how many miles you have on your jeep, 10w30 works fine. and 5w30 works fine as well. 5 Qts at walmart for $15, and I change it every 5K on the nose!

If you want to use synthetic oil, is fine in a brand new car and you new car is used to this!. If you have high miles like me 207k and you have been using regular 10w30 oil for the entire time and switch over to synthetic you will develop drips and leaks because the seals on your engine have dried up over the last 14 years and the thinner oil will leak out more. Switching back to your regular oil will fix this problem. Also once in a while I use marvels mystery oil, or at205. Just add a little bit into each oil change or once in a while. It lubricates the engine and all the seals. I have like one drip once a week or once every other week.

Also did anyone notice that walmart sells a metal tray to put under your vehicle to catch the drips, instead of cardboard.

You can switch back and forth from synthetic back to regular 10w30 oil without issues.

Keep in mind synthetic can last like 10,000 miles maybe even 15,000 miles. but it does cost more.

I believe that, my 2001 started dripping much faster after the second synthetic change, going to give the rotella t5 a shot