Old Jeep, Severe duty. Magnum 5.2.

[Dustmuffins]

Hello everyone. I drive a 1995 Jeep Grand Cherokee with the Magnum 5.2 (the earlier one with the EGR). Mileage is currently at 260,000. Cold Air Intake and cat delete are the only engine mods. 180* Thermostat. I use this badboy to deliver pizza, and I drive on about a 40 mile journey (80 round trip) to Cleveland every weekend once or twice, as well as do some off road around my property. I'd say I drive about 400-600 miles every week. Lots of engine starts in there, probably about 20-30 a week. Most are hot-warm. I have a remote starter, and am very diligent about starting up my Jeep before I get in it. Usually about 5-7 minutes before getting in when it's cold, and about 30 seconds before getting in when it's hot. When I got it, it had 188k miles on it. I kept up with 4-5k OCI with Pennzoil HM 10W-40. Here is a hint on what the motor looked like after around 220k miles: http://www.nagca.com/forum/showthread.php?t=41135 Uncleaned rockers and pushrods on the left, cleaned on the right. http://imgur.com/a/ufKTK The engine had an almost unnoticeable tick that came from the bottom end. You couldn't hear it if you were standing in front of it with the hood popped. The only way to hear it would be to lay on the ground on the driver's side. It would come and go. I continued running Pennzoil HM until about 240,000 miles. Then I switched to Royal Purple 10W-40 and RP filters because of the Pep-boys 5qt+filter deal for $40. After running RP for the last 20k miles, the slight tick has become almost impossible to hear, and the Jeep still runs great. The only noticeable smoking from the exhaust is a small puff on startup, probably leaking from the valve stem seals. I consume about a quart of RP 10W-40 every 1600 miles. I have been changing the filter every 4500 miles and draining the oil completely every 9000 miles. Here's my problem. While RP has been good to me and my Jeep, it's expensive as [censored], and pep boys has discontinued their $40 deal. I want to maintain a high OCI, preferably extend it further. I would really hate to have to roll under my Jeep every single month to do an oil change. I'm not too knowledgeable on oil, but here's the options I've considered(for reference, the manual says the oil should be changed every 7.5k with 10w30 [not sure if conventional or synthetic]):

• Sticking with the best stuff I've used so far and buying Royal Purple in bulk , adding oil as needed, doing a 12k Oil Change Interval/Filter Change Interval.
• Buying Amsoil Extended Life 10W-40 in bulk, adding oil as needed, with a 9k OCI/FCI.
• Buying Amsoil Premium 10W-40 in bulk, adding oil as needed, with a 12k OCI/FCI.
• Running Shell Rotella T6 5w-40 with a 7.5k OCI with Fram cheapy filter.

I would also run about half 5W-30 in the winter in the Amsoil or Royal Purple options, making me sit at about 8W-35 for the cold Ohio winters. How do these options sound? Would there be better options out there for me? How about the oil change intervals? Thanks for reading my huge wall of text!

 

[mechjames]

I'm running Amsoil Signature 0w30 in my 5.2 magnum, engine is nice and quiet, and starts up easy. Nice mpgs from a V8 too.

 

[Merkava_4]

I'm thinking Maxlife 10W-40 would be perfect for your application.

 

[Dustmuffins]

Maxlife sounds interesting because my motor had slight buildup the last time I had it apart. what kind of OCI would I be looking at with my severe duty cycle? Anyone have advice on the Amsoil and Royal Purple OCIs that I laid out in my first post? Could I run that oil longer?

 

[Merkava_4]

How many miles do you put on in 6 months ?

 

[Dustmuffins]

Probably around 15-16k. Severe duty. That's why those more expensive oils seem like good alternatives. I've done ~16k since the end of may: http://www.fuelly.com/driver/dustmuffins/grand-cherokee You can click "view all fill ups" to get a good idea of my mileage.

 

[addyguy]

How do you make any money delivering pizza in a V-8 SUV?

 

[A_Harman]

AMSOil's main claim to fame is extended oil drains. 15k miles in 6 months seems to be right up their alley. Another possibility would be M1 Extended Performance in 5w30. Or M1 0w40. It has a freakishly high TBN for a gasoline engine oil.

 

[meep]

keep in mind he's replenishing a quart every 1600 miles-- every 3 weeks at his mileage. This really isn't a situation where he needs a long-life oil since its being replenished often. I'd drop the boutique oils like RP and wouldn't really consider amsoil unless the consumption gets fixed. Maxlife or a 30-wt Rotella. Great oils for a lot less money. Really, he could run a dino oil and be ok-- most starts are warm, oil spends most of its operating life warm, and it's getting replenished monthly. M

 

[meep]

Hey Dustmuffins-- are you staying up-to-date with driveline lube? Some of the ZJ rear axles don't have the best longevity, the chain-based transfer case can eat oil, and the AT's last a long time if cared for. I'd suggest: Mobil 1 syn ATF in the t-case; Mobil/Amsoil 90-wt in the axles (amsoil 110 in the rear if it's tired), and a name-brand ATF+4 in the trans (I like castrol's mix in mine). M

 

[Dustmuffins]

Originally Posted By: addyguy

How do you make any money delivering pizza in a V-8 SUV?

With a big smile on my face! I get this one a lot. I spend about 1/3rd of the tip money on gas when I deliver, so I come out on top by quite a large margin. I love driving my jeep, consequently, I love my job. “Choose a job you love, and you will never have to work a day in your life.” ― Confucius

Originally Posted By: meep

Hey Dustmuffins-- are you staying up-to-date with driveline lube? Some of the ZJ rear axles don't have the best longevity, the chain-based transfer case can eat oil, and the AT's last a long time if cared for. I'd suggest: Mobil 1 syn ATF in the t-case; Mobil/Amsoil 90-wt in the axles (amsoil 110 in the rear if it's tired), and a name-brand ATF+4 in the trans (I like castrol's mix in mine).

I already have a front end sitting outside my polebarn and I have a Dana 44a lined up for me at the junkyard that I'm going to pick up tomorrow. When I got my ZJ, it had no rear diffy plug and the pumpkin was almost dry. $1000 isn't too bad of a deal for a Jeep so I just rolled with it. I just recently swapped in an NP 242 transfer case at 242k miles(interesting coincidence, eh?), and so far so good when it comes to using oil. Thanks for the advice on lubes. I'll throw in some Amsoil 110-wt in my "new" axles and get some better lube for the transfer case next time I drain it. I'm still kind of wanting to keep going with Royal Purple becuase it's been so good, or switching to Amsoil because of all the good things I've heard about it, but I'm liking the look of maxlife. I really don't want to run a dino oil becuase of the short oil change intervals. What kind of OCI would I be running with maxlife, and what kind of OCI SHOULD I be running with a fancy-pants oil like Amsoil or RP? Any advice on filters and filter change intervals? When I use oil, does that mean that the dirt that was in that oil gets taken away as well? Would that mean that at the end of a 10k OCI my oil would be cleaner than a vehicle that didn't use oil and have it replenished? Thanks to everyone for your help and input. It's a huge help.

 

[rslifkin]

If it's burning oil, I'd make sure the plenum gasket on the intake manifold is good. It's known for failing on these, and can cause carbon buildup, oil use, and occasional startup smoke.

 

[addyguy]

For oil, I'd go with Rotella T6 5W-40. With how much you are topping off, you want an economical oil! If you are dead-set on using something like Amsoil, they have ACD 30/10W-30 that can be bought in bulk for a good price, and would still work well in the winter. I wouldn't use RP, unless you can get it for a really good price. Maybe you can find a deal/sale, but I'd say for a good, consistent price on a quality syn, Amsoil will be you best bet.

 

[semaj281]

Originally Posted By: Dustmuffins

I'm still kind of wanting to keep going with Royal Purple becuase it's been so good, or switching to Amsoil because of all the good things I've heard about it, but I'm liking the look of maxlife. I really don't want to run a dino oil becuase of the short oil change intervals. What kind of OCI would I be running with maxlife, and what kind of OCI SHOULD I be running with a fancy-pants oil like Amsoil or RP? Any advice on filters and filter change intervals? I can't speak for RP but the Signature Series Amsoil is supposed to last you at least 10k miles with their Eao filter or an equivalent extended life filter. The cheaper filters like STP, Purolator Classic (white canister), or Napa ProSelect are not designed to go past 5000-7500 miles. Some would say they are no good after 3k. As for Valvoline Maxlife, I'm willing to bet it'll give RP a good run for its money. Give Synpower a look if you're considering Valvoline. When I use oil, does that mean that the dirt that was in that oil gets taken away as well? Would that mean that at the end of a 10k OCI my oil would be cleaner than a vehicle that didn't use oil and have it replenished? I don't think so. When oil burns off in the combustion chamber, not all of it gets completely vaporized. The by products are leftover as carbon/sludge, and it'll stay until you either change the oil or do some kind of chemical cleaning (ex. Seafoam). Thanks to everyone for your help and input. It's a huge help.

 

[Dustmuffins]

Originally Posted By: rslifkin

If it's burning oil, I'd make sure the plenum gasket on the intake manifold is good. It's known for failing on these, and can cause carbon buildup, oil use, and occasional startup smoke.

Interesting. I'll check for leaks. Come to think of it, I do notice a very slight pinging on acceleration. I just dread taking the steel bolts out of aluminum. Bolt breaking city... If I do that, and that fixes my oil consumption, I'll go the Amsoil route. I figure it's down to Rotella T6 or Maxlife as long as I'm using oil at this rate. I'm going to get myself some amsoil filters. as well. The only thing I need help on deciding now is the oil change interval. Thoughts?

 

[jeepman3071]

Nothin' like a ZJ with the 5.2L V8. My friend had a '98 Limited and that thing was pretty quick for a Jeep and very fun to drive. If it was me I'd run Rotella T5 10w30 or T6 5w40 with a good filter. I'd use a Purolator classic or PureOne over a Fram. The Purolator classic is a much better filter and only $3.99 at Advance Auto. The Rotella is a heavy duty engine oil and won't burn off as quickly. My friend ran the 5w40 in his 5.2 for over 100k without issue. Sadly he hit a deer 2 years ago doing 75 mph and it was totaled.

 

[rslifkin]

I've got a UOA from my 5.9 after 6k miles on T6 from last spring here: 5.9 Jeep 6k Mile UOA on T6 With your driving pattern, I think you could go 7500 miles on T6 with no issues (longer than that gets annoying, as that's as long as you can set the computer reminder for). I had surprisingly little trouble with bolts when I did the plenum gasket on my Jeep about a year and a half ago. Took me a whole weekend though. However, I've had the intake off the thing a few times since, and could do it in 8 hours at this point, so it's not a huge project. I swapped to the thicker 1/4" aluminum Hughes plenum plate, and 16k miles later, it's still holding well. Dropped my oil use from about a quart every 2500 - 3000 to less than a 1/2 quart in 6k.

 

[addyguy]

With the amount of consumption you are experiencing, 10-12k OCI's would be a piece of cake. Honestly, if you didn't care about the vehicle as much as you obviously do, I'd say you could completely stop changing the oil; just keep it topped off and change the filter once a year.

 

[Merkava_4]

Originally Posted By: Dustmuffins

The only thing I need help on deciding now is the oil change interval. Thoughts?

What's the color of your oil look like after 3 months? How dark is it?

 

[Dustmuffins]

Originally Posted By: jeepman3071

Nothin' like a ZJ with the 5.2L V8. My friend had a '98 Limited and that thing was pretty quick for a Jeep and very fun to drive. If it was me I'd run Rotella T5 10w30 or T6 5w40 with a good filter. I'd use a Purolator classic or PureOne over a Fram. The Purolator classic is a much better filter and only $3.99 at Advance Auto. The Rotella is a heavy duty engine oil and won't burn off as quickly. My friend ran the 5w40 in his 5.2 for over 100k without issue. Sadly he hit a deer 2 years ago doing 75 mph and it was totaled.

I love it. Weather It's a mud bog or a high speed road, it's always a joy to drive. This thing has proved itself time and time again. It's awesome to be able to just go out driving and turn down almost any road you can find and not have to worry. Here's a random railroad bed I stumbled across after going airborne on a back country road: http://i.imgur.com/d2ilK.jpg

Originally Posted By: Merkava_4

Originally Posted By: Dustmuffins

The only thing I need help on deciding now is the oil change interval. Thoughts?

What's the color of your oil look like after 3 months? How dark is it?

Not sure on the timing here, but this is what the oil looks like after 4.5k miles.

Originally Posted By: rslifkin

I've got a UOA from my 5.9 after 6k miles on T6 from last spring here: 5.9 Jeep 6k Mile UOA on T6 With your driving pattern, I think you could go 7500 miles on T6 with no issues (longer than that gets annoying, as that's as long as you can set the computer reminder for). I had surprisingly little trouble with bolts when I did the plenum gasket on my Jeep about a year and a half ago. Took me a whole weekend though. However, I've had the intake off the thing a few times since, and could do it in 8 hours at this point, so it's not a huge project. I swapped to the thicker 1/4" aluminum Hughes plenum plate, and 16k miles later, it's still holding well. Dropped my oil use from about a quart every 2500 - 3000 to less than a 1/2 quart in 6k.

With regards to the computer; I was running a 9k OCI with my Royal Purple, so I just set the reminder for 4500 miles, and would rotate my tires, grease the fittings, etc on that schedule, then alternate between oiling my cold air intake air filter and draining the oil every 9k miles. That's quite an impressive improvement in oil consumption you got there. I'm ordering a new plenum gasket, intake gaskets, new distrib cab+rotor, plug wires, temp sensor, and oil pressure sending unit and I'll give my Jeep an overhaul and see where that gets me for oil usage. If this makes me consume less than a quart in 3k miles, I'll take the Amsoil 10w-40 route with a 12k OCI. If I consume more than a quart in 3000 miles, I'll roll with Rotella T6 5W-40 and an amsoil filter with a 8k OCI. Until then, I'll use up what's left of my Royal Purple Sound like a good plan?