I believe him on the 2-3 mpg gains. I have one on my 01 Ram (5.2L V8) and it sucks hot air actually, since it hangs over the wheel well. It all depends on how you drive. Mine varies 13 - 15 mpg, (consistently 14.5) depending on my foot. That's mixed driving. (city/hwy) People are surprised when I tell him the mpg, but I have a running tally since May of last year.

SJ02

 

Well, I have a durango with 115,000 miles, that gets an oil and filter change once a month (no offroading here, only highway) and I have some sort of sludge that shows up occasionally. It worries me, but still runs good. My other car is a 1994 olds, 200,000 miles gets an oil change maybe every 6000 miles, gets driven more, and not a trace of sludge.

Not trying to be a dick either. I've verified the engine oil sludge problem through some big name Chrysler mechanics, it's a common topic in almost every automotive forum, and mine is starting to do it. Don't get me wrong, I love my Durango. I would get another in a heartbeat. I love how it drives like a truck but has the comfort feel. No major issues until the back axle, which was my fault for not noticing the fluid leaked out. Every car has known issues. The durangos, as sweet of a truck as they are, have their quirks as well.

 

Now, I'll admit, You are the first person I've ever heard to claim an increase of over 3 MPG. But I did a little experiment last summer with mine versus the factory one. Aside from the MPG, it gives mine a bit more get up and go, especially on the freeway or hilly highway. It runs better with the new one I got. It was one of those things I had to try to believe. Will forever be a debate in the auto world.

 

I don't think I'll do that to the Durango tho. Maybe just pop in a K&N replacement filter and be happy. We'll see though. (gotta see if that TC replacement fixed my issues first)

SJ02

 

I still stand by what I said, the only reason there will be sludge is from poor maintenance. Shrp knows way more about the 4.7 than me so I'll let him explain what's being done wrong.





I only noticed maybe a 1/2 - 1 mpg difference on the highway, but that's it. I usually get 17-17.5 mpg on the highway, but if I'm careful I can get 18 mpg. I usually average 13.5 -14.5 mpg.

 

the 4.7 has a known SNOTTING issue, its yellowish whit sludgy build up in the oil filler cap, THIS IS NOT SLUDGE!!!!!!!!!!!!!!!!!!!!!!!!!!!! it is simply water residue that doesnt get boiled out all the way, it is caused by making frequent short trips that dont warm the engine up all the way, or that dont run it long enough after it is warmed up. This is aggravated by the fact the PCV valve is NOT located at the highest point in the engine (woops). other than that there are no known oil related issues caused by manufacturing or design, NO SLUDGE, no nothing if you change the oil at the factory recommended interval (7500 miles, check your owners manual if you dont believe me).

I change my oil in my 4.7 at 5k mile intervals bc i do a fair bit of idling driving for work and 5k miles is easier to remember than 7500 (IMO), i have an oil analysis done every couple of changes, and EVERY SINGLE TIME it has come back with NO particulate (sludge) in the oil, if you would like to see this report for yourself i will be more than happy to post it. (this was even the change interval when i was attending school and 5k miles took 8-10 months to put on and 0 issues).

P.S. i have 118k on mine

im letting the other guys handle the CAI issue, but when i did my homebrew intake i gained about 1 mpg, and that is a generous estimate, i get 20mpg highway out of mine if i behave.

 

Called it

 

I agree with you and know what you are talking about with the gunk around the filler. It worried me before I bought it, so I looked it up online...common, generally harmless issue. But the fact that there are so many complaints and siezed up Durango 4.7 engines over the years, has to mean something. Sure some people abuse their maintenence. But there are plenty of people who properly maintain their engines who have had sludge problems in these. Next time I'm on the computer, I'll post several links regarding the oil issues. They explain it better than I can by memory. It's rather interesting reading. In fact, I'm pretty sure I remember seeing big long threads in here that explain the issue. I'll post links tonight or in the morning.

 

With the cai, I get about 17 highway, if im having a good day. Before the cai, 14 - 15. Not huge, but it helps. Plus it makes it sound a bit tougher. If it doesn't help your fuel economy, at least it sounds cool when you jump on the gas

 

i gaurantee that the people with seized up engines from sludge (truely sludge, not just saying it) is from lack of maintance, and i also gaurantee that not every case is actually a sludge issue as they are really not all that common, it is a very often misdiagnosed issue (misdiagnosed as in sludge is blamed for problems it is NOT responsible for) without pictures of the sludge i will NOT believe ANYONE claiming that they have sludge because it is so very very easy to misdiagnose and seems to be a favorite for mechanics because it means lots of money to rebuild and clean out the engine