Jeep Owners!

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Aug 7, 2004
I have a 99 Wrangler with the 2.5L with 34,000 miles. I have been looking over the forum for the better part of the last 2 hours and have seen many of you 4.0 owners are running rotella or some other kind of 5w40. I currently run Mobil 1 10w30 and have since it had 24,000 miles. I was wondering why everyone with a jeep has been putting 5w40 in their jeeps and if I would get anything out of changing my oil weight in my little 4 banger 2.5L? I am sure the owners manual says to run 10w30 and cannot find the benefits of running a 5w40 in any posts. I have also been changing my oil (M1) and filter (K&N) at 3 months or 3,000 miles whichever comes first and outside of this site many in the jeeping community has agreed on that. However, I come on this site and it seems as though everyone says it's ok to run mobil 1 for 5k-10k. I have learned about (UOA) but it is hard to go against everything you have been told for years and years!!. With this short change interval am I just throwing money away?
Yes, 3K with Mobile 1 is short. While the short OCI won't hurt the engine, you can probably double that and save yourself some money. I have 2 Jeeps-a 2000 Wrangler 4.0 (62K) and a 1996 Cherokee (130K). The Cherokee has had Mobile 1 10W30 since it was new and still runs perfect, and uses no oil. I run 5500-6500K OCI's. I traded in my 1994 Dakota with 197,000 miles on the 2000 Jeep and it still ran perfect. Approx. 6K OCI's with Mobile 1 10W30 since new, lot's of towing on the V6. I'm doing my first UOA on the 2000 Jeep so it will be interesting to see where it stands. The 96 will get it's first UOA next weekend. Needless to say, I have no problem with Mobile 1 and 5-7K OCI's. But to get a real idea how it's performing you'll need to do a UOA. I'd be cautious about going over that without one to back you up.
The main thing with the 5w-40s is that they are typically HDEO oils designed for diesels. They have very potent additive packages. I'm up to 12.5k on my wife's 4.0. 10k was a snap for Delvac 1. If I can't stretch it to one year (18k) with her 10.5 quart capacity, I'm going with 6month OCI with Rotella, which is half the price. On my 4 banger (02 SE, I just do 6 month OCI. This varies between 6-7k. I mainly do this due to the 4 quart sump, which I think is inadequate. I'm currently using Agip PC 5w-40. Unless you're doing some severe duty (short trips, high speed/hot weather, dusty conditions, etc.) you're really wasting money with the Mobil 1 at 3k/3m IMHO. btw-trail use would constitute severe duty IMHO if you wheel ..sure keep the high maintenance schedule ..but I'd dump the M1 for Rotella just to save some cash. Don't feel bad. Many here are trapped in the 3k/3month prison. In fact, many seem to discount and ignore bona fide evidence to the contrary and still shy away from extended OCIs even to factory recommended limits.
I run 15W-40 Schaeffer PAO Blend in my 2.5L. I have an remote filter and run the Wix 51773 1qt filter so my sump now holds 5.25qts instead of the stock 4qts. My UOA on M1 10W-30 was allright looking but I think these engines like a thicker 40W oil.
Just my opinion (based on nothing), but I'd ditch the K&N filter if I were you. Flows a lot, but not so much filtering. Of course, many will disagree. I've been using 10W30 for 98K on my 96 Cherokee. I'll do a UOA one of these days....
What would be the positives to switching to a synthetic 5w40?
I've always used synthetics when practical. I'm also into extended drain intervals. Others may offer alternative opinions, but in this case you get all the advantages of a heavier oil (our jeeps appear to like the thicker stuff), yet give you adaquate low temperature flow characteristics. Couple that to a robust additive package and you've got a great oil for extended drains and superior protection. My 9k UOA with M1 x-30 was pathetic compared to the 10k with Delvac 1 (5w-40). my first UOA Delvac lowered my wear numbers radically over a longer duration. The trade offs. You'll be spending more energy to pump the stuff through the engine. This isn't much of an issue with a 2.5 or 4.0. It may be with some Japanese designed sewing machine that can barely keep itself running at idle. These engines were never designed with economy in mind. Limited availability. You won't find them just anywhere ..especially Delvac 1. M1 T&SUV is allegedly the same thing ..but the debate goes on. If you like to play with your oil [Big Grin] : If you change it too often costs you too much. It kinda all depends on your attitude toward lubrication (the extent that you go to) and your goals. I'm into giving good protection over the longest span ..others are not so interested in getting high mileage out of an oil change. If you're not into extended drains or severe duty may be better served with a common dino (actually there are many exceptional dinos available). btw-Did you tell us what "service duty" you put your jeep through. Highway commuter, suburban sortie, rural route, or "urban assault"?? Combo??
I put about 1,000 a month of stop and go commuter traffic. I would say about 400 of those miles are highway miles though. I would like to get atleast 200K or more out of my engine. The idea of changing my oil every 5 months or so frightens be but at the same time excites me!
For anyone that owns a Jeep, especially the 4.0, what is the average oil consumption you get? I am getting about half a quart for every 7K miles (4.0, Amsoil 0W30).
My '01 with ~45k miles has used no detectable oil in the ~9k miles I have driven it since April. I just put in Amsoil AFL 5w-40 after a 5k run on ATM 10w-30. I plan on running 7500 miles OCIs, but if I actually do a UOA that may be stretched a bit. A little too early to tell, but I don't think my mileage went down at all with the 5w-40. I think I have found my ideal year round oil in this cold climate.
My 99 XJ with 140,000 kilometers and my 01 TJ with 91,000 KM. have no noticeable signs of oil use since I bought them...both new...both 4.0L engines...both were on Mobile 1 10W-30 since "birth in Toledo" and now are on Delvac 1 5W-40 still using the NAPA Gold 1515 oil filter on both.
My 95 YJ w/ 2.5 burns about half quart per 4000 miles. I use Delo 400 15W40. It is frequently used in dusty conditions and I change oil every 3000-4000 miles. The engine is clean inside with 102,000 miles.
I use 10W-30 Mobil-1 in our 4.0 every 5,000 miles (ignoring months) along with a SuperTech filter. The 1998 Grand Cherokee has 152,000 miles. I would do the same for the 2.5L (except use two less quarts) [Wink] -John [Cool]
My 4.0 "seeps" about a quart every 18k out of the remote fittings (average if I actually had to add a quart-so far the OCI interrupts it). My 02 2.5 moves down on the dipstick at about 6k ..which is when it's changed. This consumption is just about the same regardless of how I drive it. Highway commuting at warp speeds (not easy in a 2.5 [Big Grin] ) or just tooling along in rural/suburban rolling hills of PA.
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