Experts.... need help with oil choice

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1,397
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Katy, Texas
I am currently a high school student. I don't drive very much. Just to give you an example, i've put 2,500 miles from June til today. My school is less than 1 mile away. Every morning, I pick my friend up (1 mile away), drive my sister to school (2 miles total), then to the career school (4-5 miles), getting on the highway in the process. At mid day, i drive back to my home campus and let the Jeep bake in the 100 degree sun. After school, i drive home. 20 min later, i'm back up at school for band. 2 or 3 hours later, i leave. Thats my daily routine. I do drive around town sometimes. I am currently running an O'Reily Auto Parts oil filter (Purolator Premium Plus) and Mobil Drive Clean Plus. I am considering going over to Mobil 1 on my 95 Grand Cherokee. It doesn't leak, it has 69K miles. I know I can make the swtich without problems. When i start up in the morning, my oil pressure is about 60 psi at idle. Thats the max PSI it should be on a 4.0L i-6. When i start moving, it gets to 65-67 but 65 is the max when moving. Should i let the Jeep warm up a little b4 i drive it? I dunno if thats the pressure going into the filter or coming out. If its the pressure going in, then its ok because the pressure drop on a Purolator Premium Plus is enough to put it back into the safe range. So, should I just run a high quality dino oil or blend like I am now, or swtich over to Mobil 1 for the extra protection. It gets hot down here. It will be hot til the end of Sept - mid october. Sorry for the long length! Thanks in advance!!! [ August 20, 2003, 07:13 PM: Message edited by: JeepZJ4.0 ]
 
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College Dorm...
Been there done that...now I'm in college and have to drive a few miles to the other side of campus five times a week. I'm not really an expert, but I'm gonna suggest a HDEO (Heavy Duty Engine Oil), either a 5w-40 such as Rotella-T Synthetic, maybe 5w-30HDD Amsoil or a 15w-40 such as Delo or Delvac. The 4.0 I-6 also seems to do well with thicker (40 weight) oils. ...Suggest this because the higher TBN will help neutralize any acids that come from your engine not getting up to operating temp. Also the heavy-duty oils can deal with high heat very well. If you don't mind spending a little more, I'd also suggest a K&N oil filter. Filter good, but more importantly, they flow very good as well. [ August 20, 2003, 07:29 PM: Message edited by: Jelly ]
 

Patman

Staff member
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Guelph, Ontario
quote:
Originally posted by JeepZJ4.0: Is it safe to use a 15W-40 in the winter? I gets to freezing here sometimes.
If you rarely see temps below 32F, you'll definitely be fine running 15w40.
 
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2,569
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College Dorm...
quote:
Originally posted by JeepZJ4.0: Is it safe to use a 15W-40 in the winter? I gets to freezing here sometimes.
I've heard it both ways before...that you could and couldn't. Personally, I believe you can. Modern CI-4/SL 15w-40's, such as Delvac and Delo (but not Rotella), have pour points in excess of -30F and, on top of that, actually pass 10w pumping requiremnts. I've been told the only reason they keep the 15w-40 title is because 15w-40 is know as the "strong, diesel grade" where 10w-40 is known as a gas engine grade, weak, and sludge prone (from the old days). [ August 20, 2003, 08:27 PM: Message edited by: Jelly ]
 

Al

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Elizabethtown, Pa
Honestly you can keep doing whar you are doing. I would not use a 5W-xx oil where you are. a 10W /15W 30/40 in dino or synthetic is fine for you. I think the Delo 400 or Delvac 1300 is probably superior to the Rotellla T. In dino- Motorcraft, Pennzoil or Chevron Supreme. If you go with Mobi 1 you probably can go 8K or 1 year whichever comes first easily. If you go extended with synthetic I would change filters halfway or Use a K&N which is easily good for 10K.
 
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You didn't say how often you change the oil. That makes a big difference on which oil you might want to use. If cost is a factor, I'd use Mobil Drive Clean and change every 3-5k miles. Syn's aren't worth it on a student budget.
 

JeepZJ4.0

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Katy, Texas
I change it every 3K miles on dino oil. I know Mobil 1 has the ability to go for extended drains. If a heavy duty grade oil will give me more benefit or equal benifit to M1 or a syn, then i'll change it ever 3K. Budget isn't that much of a concern to me. I really want this Jeep to last (which it will... its a Jeep) since its my car for college and beyond. What about Pennzoil Long Life HD oil? It has moly in it. I think i'm sold on an HD oil. [ August 20, 2003, 10:59 PM: Message edited by: JeepZJ4.0 ]
 
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I wouldn't use a 15w-40 in the Jeep. I have a 95 Grand also, and the startup pressures are 65lbs. With a 15w-40, this would be 80lbs. I use stick with the oil you are using.
 

JeepZJ4.0

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1,397
Location
Katy, Texas
quote:
Originally posted by JonS: I wouldn't use a 15w-40 in the Jeep. I have a 95 Grand also, and the startup pressures are 65lbs. With a 15w-40, this would be 80lbs. I use stick with the oil you are using.
Eeek...... i thought it was vise versa... thicker oil, lower pressure.....thinner oil (like a 5wXX) would give higher pressure. Edit: If this is the case... where can I buy Delo in 10W30? I know its avalible. [ August 21, 2003, 04:02 PM: Message edited by: JeepZJ4.0 ]
 
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Checker auto has Delo 400 in the 10w-30 here in MN. But i would not use a deisel oil in the Jeep. I had to get the Cat. replaced on mine because the mechanic said someone probably used a deisel oil in it. They have ash that will clog up the cat. He told me if my cat. converter clogs up while driving, it would seize my engine.
 

Patman

Staff member
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Guelph, Ontario
quote:
Originally posted by JonS: Checker auto has Delo 400 in the 10w-30 here in MN. But i would not use a deisel oil in the Jeep. I had to get the Cat. replaced on mine because the mechanic said someone probably used a deisel oil in it. They have ash that will clog up the cat. He told me if my cat. converter clogs up while driving, it would seize my engine.
He's being a bit overdramatic there. You can tell that your cat con is starting to get plugged up, so unless you end up driving your car for months and months until it's 100% plugged up, you won't seize your engine. I know guys who have had their cat cons begin to fail, and they notice the cars performance drop off quite a long time before it ever reaches the critical stage. You'll usually see your MPG get really bad too. So in other words, you'll have time to fix it long before it becomes a major problem.
 

JeepZJ4.0

Thread starter
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1,397
Location
Katy, Texas
quote:
Originally posted by Patman: He's being a bit overdramatic there. You can tell that your cat con is starting to get plugged up, so unless you end up driving your car for months and months until it's 100% plugged up, you won't seize your engine.
But is it really due to a diesel grade oil? Thats weird! There are guys on here using Diesel grade oils in their cars. The 40W does well on the 4.0L and the UOAs back that up. [ August 21, 2003, 04:47 PM: Message edited by: JeepZJ4.0 ]
 
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I too vote for the 15W-40. I run this in my 96 ZJ 4.0. The 4.0 has loose clearances and likes a 40 weight. I’m currently running Schaeffer’s Series 7000 15W-40. Good stuff. If you have a Costco (and are a member) they carry Chevron Delo on the cheap. Delvac 1300 is also a nice choice.
 

JeepZJ4.0

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Katy, Texas
quote:
Originally posted by darrenc: I too vote for the 15W-40. I run this in my 96 ZJ 4.0. The 4.0 has loose clearances and likes a 40 weight. I’m currently running Schaeffer’s Series 7000 15W-40. Good stuff. If you have a Costco (and are a member) they carry Chevron Delo on the cheap. Delvac 1300 is also a nice choice.
Sweet! How long have you been running it?
 
I am a Chrysler /Jeep certified technician,own 2 4.0L Cherokees and use 15w40 in all of my engines.I also change my oil at a 3mo/3000 mile interval.I'm using Wally Mart Super Tech oil along with the Super Tech filter,no problems.Our last 4.0L Cherokee had over 150K before it was totalled.I live in Florida,and it gets hot here too. However all being said... I'd keep using the Mobil dino that you currently use(you didn't mention the weight-should be 10w30 at least) and the O'Reily filter,along with your change interval. As far as warm up,I have always let my engines run for about 20 seconds before I back out of the driveway. If you decide to switch to 15w40,that would be fine,although don't worry about it tearing up the cat converter or causing the oil pressure to go higher.I would use either the Chevron Delo or the Mobil Delvac 1300.Both are reasonably priced at Wally Mart. Also switch your oil filter to the largest possible size.Whatever the equivalent of a Fram PH8A in the O'Reily line will fit. Hope this helps... [ August 23, 2003, 05:02 AM: Message edited by: Chris 2421 ]
 

JeepZJ4.0

Thread starter
Messages
1,397
Location
Katy, Texas
quote:
Originally posted by Chris 2421: I am a Chrysler /Jeep certified technician,own 2 4.0L Cherokees and use 15w40 in all of my engines.I also change my oil at a 3mo/3000 mile interval.I'm using Wally Mart Super Tech oil along with the Super Tech filter,no problems.Our last 4.0L Cherokee had over 150K before it was totalled.I live in Florida,and it gets hot here too. However all being said... I'd keep using the Mobil dino that you currently use(you didn't mention the weight-should be 10w30 at least) and the O'Reily filter,along with your change interval. As far as warm up,I have always let my engines run for about 20 seconds before I back out of the driveway. If you decide to switch to 15w40,that would be fine,although don't worry about it tearing up the cat converter or causing the oil pressure to go higher.I would use either the Chevron Delo or the Mobil Delvac 1300.Both are reasonably priced at Wally Mart. Also switch your oil filter to the largest possible size.Whatever the equivalent of a Fram PH8A in the O'Reily line will fit. Hope this helps...
Thanks! I use 10W30 Mobil Drive Clean Plus. If I go to PH8A size, (same as the Motorcraft FL1a), how much extra oil should I add?
 
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