I've been changing my oil at 2500 miles for at least two decades, on all my cars and trucks. However, that's been with conventional oil, and in the case of my XJ, with Mopar filters.
About a year and a half ago, I switched to Chevron Delo semi synthetic 10w30, and if I can't find it affordably, then Rotella T5 10w30 is my back up choice, and always with Napa Gold filters. I use that in all my vehicles now. And, its time for oil changes again on my wife's WJ and my XJ (both with the 4.0) and this time, both oils still look clean, light brown, surprisingly good looking in comparison to previous oil changes, and has me now wondering if I'm changing too soon with the oil/filter combo I'm running?
What'da think?

 

Sounds a little premature to me. I'd run around 4,000 with that setup and you could probably go longer than that. Factory interval for standard service is 7,500.

 

There's certainly no harm in doing the oil change so early, but it's definitely not necessary. I do 5k intervals in the family car (Corolla) and I've done two changes on my XJ, the first when I got it, the second after about 3500 due to it being about 8 months since I'd done the previous change.

 

Sorry folks. I should have used the "search" feature, seems I asked this same question back in February. My apologies.

 

 

 

I change mine in February when I have some spare time. The straight weight 30W Castroil I can use here in CA likely could last longer then the 8K or so I do in a year. (next it's bar oil for my saws)

One is near, and the other just passed 300K, both runnin fine and strong. Don't use that on drill-bits or saw-blades BTW, they won't cut well.

 

I always figured every 6 months or 6000 miles with a good oil. With regular oil I would change a little bit sooner (maybe 4 months 4000 miles), but synthetic should be fine to 6000 if you are not beating on it.

 

FWIW, I do mine twice a year with a vehicle that sees no more than 8K miles. I use Mobil 1 10w-30 that I get at Costco when they have the $10 off a case sale price. I like the thought of my motor having fresh oil in it

 

Every 5,000 miles or once a year for me.

 

On most of my vehicles, I change at 5k to 6k miles ...conventional oil (Citgo). 10k to 12k miles for my diesel car (using Shell Rotella synthetic).

I use Citgo regular oil that I can buy cheap at the local Farm n Barn ever since I could drive ....that's over 35 yrs ago, and never had an engine let go or start smoking. I've run a Jeep 4.0 ZJ up to 320k miles and it still runs great, no smoke. Have a WJ with 212k 4.7 that runs great and several other cars/trucks up to 200k mi ...all on conventional Citgo oil folks!! You can badmouth it all you want, but the good results speak for themselves. For filters I use either Mopar, Bosch or Napa Gold ...never Fram (they suck).

Now, on my dodge Ram 5.7, I use Penzoil Ultimate Synthetic. You can get it on sale sometimes fairly cheap. And on my XJ, which I don't drive very much (snow plow tk), I use Citgo Full Synthetic and change it about every 3 years.

 

I probably change my oil at 1500 miles. My situation is different. Despite the Jeep being a DD and the only vehicle I own that is pretty much the amount of miles I have put on it in 6 months. Being older, living 1/2 mile from work, not having a life, etc. LOL. So all my maintenance is done in terms of time and not miles. Every April, 10W 30, and October, 5W 30, she gets an oil change.

 

I just split the difference between all the maintenance items in the manual between severe duty and standard

so I do my changes at 5k miles but it could certainly go longer if you really want to know pull a sample and send it off for analysis

 

Jeep Service manual for my 98 XJ has two maintenance schedules

SCHEDULE—A
7,500 Miles (12 000 km) or at 6 months
† Change engine oil. † Replace engine oil filter.

SCHEDULE—B
3,000 Miles (5 000 km)
† Change engine oil. † Replace engine oil filter.

Schedule—A, lists maintenance recommended for vehicles used for general transportation.

Schedule—B, lists maintenance recommended for vehicles used under the following conditions:

† Frequent short trip driving less than 5 miles (8km)
† Frequent driving in dusty conditions
† Frequent trailer towing
† Extensive idling
† More than 50% of your driving is at sustained high speeds during hot weather, above 90°F (32°C)
† Off road driving
† Desert operation
Where time and mileage are listed, follow the interval that occurs first.

I think the service intervals are written before synthetic motor oils became mainstream. There are Xj owners with 4.0L, who have used Mobil One Synthetic extended motor oil and filter. (both oil and filter are rated for up to 15k) that just changed the oil and filter every 15k without any problems.

The 4.0L engine isn't all that refined as many modern aluminum block engines, however imo it's tougher than most refined alum block engines and typicality achieves 300,000 miles and higher, some have gotten over 400,000 miles with only normal repairs such as replacing the alternator and other parts connected tot he engine.

I think if driving as Schedule B yes you need to change every 3k and possibly 2.5k, however for common driving (not similar or listed under Schedule B) you can potentially go up to 7,500. I think it depends on driving conditions & habits, the type of oil and filter your using and other vehicle maintenance (the engine connected and works in conjunction with the condition of the entire vehicle).

Personally while regular duty (schedule A) I changed motor oil every 4 to 5k in my 98 XJ using Mobil One synthetic. Currently with ~203k it has Mobil One high mileage synthetic motor oil installed the last several motor oil changes. I also use either Mobil One or Amsoil oil filters, found by the case, cost $8..00 per filter Also early on switch from the small filter to the larger one that holds more dirt, etc. I find using synthetic oil and larger synthetic filters gives me more leeway between oil change intervals especially when off-road sever duty at 3k intervals.

I probably could perform an oil and filter change every 7,500 miles (schedule A), however I want the XJ to last a while, trying for at least 300,000 miles from the 4.0L, possibly ~350,000+ miles.

There are people who claim to have over 400k (iirc close to 450k) on the original XJ 4.0L engine (purchased brand new) without any overhauls and the XJ is still running ok.

 

I do a 20k interval on the 95 which is on its way to 300k. The 96 gets changed every 5k.