Jeep Garage  - Jeep Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
185 Posts
Discussion Starter · #1 ·
Hi. I own a 2005 3.7. I have owned it since 18k and now have 91k. I have always done my own maintenance and such. Now I KNOW with conventional oil my truck will get 3k miles before I notice power loss loud engine stuff like that, mpgs too. Now the last time I changed my oil I switched to a synth hoping for longer life better mpgs. Well I def got better mpgs but the oil did not out last the conventional any longer than normal. See from what I read, (i ride motorcycles and for anyone that's in a forum knows those guys are crazy about oil) everyone makes it seem like oil holds up to this and does this and that. See your oils might hold up to high temp and not lose its vicous properties, but it still gets DIRTY. All that dirt and byproduct from the air and combustion dirty the oil causeing the premature wear in parts. Also it breaks it down. Synth is a sham just like I always thought. You can't keep oil clean! Ill keep it in for the mpgs though.
 

·
Registered
Joined
·
989 Posts
Synthetic oil is not a sham. Some people just don't understand what its intended use is.

Yes, all oil get dirty. Yes, you probably shouldn't leave your oil in for 10,000 miles without verifying it is still up to the job. Synthetic oil is not designed for this. You can buy both synthetic and conventional "long life" oils, that are designed for this purpose, but that's a different story all together.

The primary advantage of synthetic oil is a broader range in which it maintains its specified viscosity properties. That is, it remains stable at much higher temperatures and has a much lower pour point. If you live or drive in such a way that these properties are beneficial, then it is money well spent.

This is why all manufacturer's warranties and recommended service intervals do not list separate times/mileages for synthetic vs. conventional oil.

P.S. I have never heard of anyone being able to "hear" dirty oil, or feel power loss associated with oil that is past its prime. If you are concerned about oil quality, send it off to a lab to be tested. This is the only way to accurately determine if your oil has outlived its useful life. Otherwise, change it at the specified intervals and driving conditions listed by the manufacturer. You'll be changing your oil (most likely) more often than you need to, but you can certain the oil still has life left.
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #3 ·
I dunno when my car starts running rough and getting crappy gas mileage, is loud, that "sounds" like an oil change. Wanna picture of the dirty, thin oil. 3k miles right on time.
 

·
Let's Roll
Grand Cherokee
Joined
·
13,095 Posts
this thread is soooo full of LOL! why don't you send your oil out to be analyzed instead of making bogus claims that your MPGs changed based on what oil you used and that it dropped right at 3k miles. you can have conventional oil in there for 5k+ miles and have it analyzed and it may still be determined to be useful.
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #5 · (Edited)
I calculate my mpgs. And when my car starts running rough around when I need an oil change I think ill change it. 3k-3.5k this truck runs like garbage. I dont run it hard and use an oil that Chrysler says is ok for use. Only noticable change was mpgs. Went in like oil came out like water and dirty. Wix filter being used. Just saying. Also like to add I'm 100 percent in tune with my motors. I listen to them run constantly. And I know what they should feel like. Noticeable change with fresh oil. And yes 3k and my mpg is terrible. Maybe calculating yours the real way instead of a computer telling you and you might see change as well.
 

·
Let's Roll
Grand Cherokee
Joined
·
13,095 Posts
you have engine problems then, I have gone up to 15k miles on synthetic and up to 5k on dino oil. no problems at all with over 150k on the clock. my wk is a business used vehicle so very good records are kept for tax purposes
 

·
Registered
2007 GC Lmt.
Joined
·
84 Posts
I agree with Svenska and Doc on this one. There is simply no way that an oil change would significantly impact your mpg, unless your oil is so bad it has no lubrication qualities left. In that case, I suspect you have some severe mechanical problems that cannot be fixed by a simple oil change. Granted, I can agree with you that the GC's can be very finicky in terms of how they run. My vehicle varies in how it runs, meaning at times it will run rough at idle speeds and have some shaking to it. But I chalk that up to Chrysler being a low quality brand, not the condition of the oil.
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #8 · (Edited)
Like I originally stated, ive had the car for over 70k miles. I can't believe nobody notices this. Same with the diff fluids when you switchem out you get mpgs back. I can tell when my car needs an oil change. Been around motors my whole life. At 91k not a single problem.there is also more power loss than just at the point of combustion. Broken down oil means less lubricant for the motor, vibration, just plain not doing its job results in a harder working motor. Car just floats now. I'm getting around the same mpg as any one else. If my motor was bad it would have happened a long time ago. I've done tons of 3.5k interval oil changes. No problems. I don't understand why all the sudden my motor is bad when I notice every time it runs rough and needs an oil change and switch it out and its golden!
 

·
Registered
2007 GC Lmt.
Joined
·
84 Posts
If I may ask you, how do you measure increase in mpg when changing oil or differential fluids? Also, how do you measure the increase in power? I am sorry if you interpreted my comment as if you had a bad engine. That is not what I meant. All I meant to say is that if you actually do experience a significant drop in performance, idle or mpg when the oil gets close to 3,000 miles of driving, I think there are other issues going on with your vehicle. Today, engine lubricants have come so far from the dinosaur oil that used to be the standard. In fact, many manufacturers are recognizing the better quality of engine lubricants and have adjusted their service schedules accordingly. Changing your oil every 3,000 miles is not a bad idea, but it is not always necessary, depending on how you drive and the overall driving conditions. If you truly believe that an oil change remedies all the issues of rough idle and decrease in mpg, I would very much like to know what oil you are using, because it must be magic in a can!
 

·
Registered
2014 Jeep Summit
Joined
·
987 Posts
If I may ask you, how do you measure increase in mpg when changing oil or differential fluids? Also, how do you measure the increase in power? I am sorry if you interpreted my comment as if you had a bad engine. That is not what I meant. All I meant to say is that if you actually do experience a significant drop in performance, idle or mpg when the oil gets close to 3,000 miles of driving, I think there are other issues going on with your vehicle. Today, engine lubricants have come so far from the dinosaur oil that used to be the standard. In fact, many manufacturers are recognizing the better quality of engine lubricants and have adjusted their service schedules accordingly. Changing your oil every 3,000 miles is not a bad idea, but it is not always necessary, depending on how you drive and the overall driving conditions. If you truly believe that an oil change remedies all the issues of rough idle and decrease in mpg, I would very much like to know what oil you are using, because it must be magic in a can!
I always thought seafoam was magic in a can lol
 

·
Registered
JEEP
Joined
·
437 Posts
Hi. I own a 2005 3.7. I have owned it since 18k and now have 91k. I have always done my own maintenance and such. Now I KNOW with conventional oil my truck will get 3k miles before I notice power loss loud engine stuff like that, mpgs too. Now the last time I changed my oil I switched to a synth hoping for longer life better mpgs. Well I def got better mpgs but the oil did not out last the conventional any longer than normal. See from what I read, (i ride motorcycles and for anyone that's in a forum knows those guys are crazy about oil) everyone makes it seem like oil holds up to this and does this and that. See your oils might hold up to high temp and not lose its vicous properties, but it still gets DIRTY. All that dirt and byproduct from the air and combustion dirty the oil causeing the premature wear in parts. Also it breaks it down. Synth is a sham just like I always thought. You can't keep oil clean! Ill keep it in for the mpgs though.
Why would you be changing oils anyway?

You just realized that oils made a difference in MPG and performance. Well thats a good start. :sleepy:

Me personally I have always ran a Synthetic, primarily mobile one, with a mobile one filter. The filter is one of the biggest elements in the longevity and usefulness of the oil.
 

·
Banned
Joined
·
909 Posts
I dunno when my car starts running rough and getting crappy gas mileage, is loud, that "sounds" like an oil change. Wanna picture of the dirty, thin oil. 3k miles right on time.
you really need to send youre oil out to be analyzed, because it really sounds like you have other issues.Blackstone Labs
i have a jeep with a 4.0 litre with nearly 320,000 miles on it and at 3,000 miles the oil is still clean looking i dont change it till 5,000 miles and even than its not totally black, and never thin and watery looking, unless of course you forgot warm oil out of a hot motor is thinner than room temp oil.
and fyi there are filtration systems used on semi trucks that allow up to 300,000 mile intervals on oil changes,with only filters changed at regular intervals, oil dosent wear out it just gets comtaminated heres a few examples of how long oil can and does last, Trucker Testimonials
so either you have other issues with youre motor or you are just tossing money in the trash
 

·
Banned
Joined
·
909 Posts
I wanna know what kind of diff fluid you are using that increases your mpgs!
read up on motorkote many many truckers swear by it and i can tell you from my experiance it lowered my oil temp by 40 degrees in our semi, can be used anywhere diffs, motor, power steering anywhere there is a lubricant great stuff
 
1 - 17 of 17 Posts
Top