I commend you on your determination to solve yours and others issue of whistling with your Nitro. It appears that no one at present has a definitive solution anywhere since I have seen your posts in several Forums. Is this only a Nitro Issue? A 4.0 R/T issue only? Have you seen or checked with 2008 Jeep Liberty owners Groups or Forums? I am sure you will prevail in your quest.
I have always told people to take their cars to their Dealership for service, after being an Automotive Parts Manager, years ago. When they reply, why would it make any difference, a mechanic is a mechanic? I always tell them first off their work is guaranteed at a Dealership, and second off 99% of the time if you have a problem they know exactly how to fix your model since they have seen it before!
Well at present you are in the 1 %, I guess.
I remember when Chrysler had an issue with their in-dash amp gauge on their New Yorker. Not only would they not charge, but most would not even start. Customers would have their car towed to a garage where a mechanic not knowing of this issue would start replacing the battery, starter, starter relay, voltage regulator, ignition switch and anything else before it ended up being towed to our Dealership. When I asked them why they didn’t bring it back to the Dealer they bought it from, they said it was too expensive! Yes it did require the replacement of the dash gauge, but it was made out of plastic and was not expensive. I even saw customers that were under factory warrant do the same thing.
Lots of strange things cause issues with cars. I remember a high squeal coming from engines with Motorola alternators that required replacing the diode package. I bet that one drove many owners (dogs too) and mechanics crazy until it was figured out! Again Dealers were the first to know and it was not as expensive as replacing the alternator that may have the same squeal and was covered under warranty.
I may be wrong but if this issue has shown up in the new Jeep Liberty I would think there may be a better chance to see a TSB issued by Chrysler as to its repair. I don’t think Nitro is at the top of their repair list at present. You did register your complaint with Chrysler as other have at Chrysler Customer Assistance Center didn’t you? Interesting to see how they respond to several complaints on the same issue! Again good luck!
I was told by the dealer that this whistle is not caused by the same thing as the whistle on the 3.7L motor. To my knowledge no Liberty model has the 4.0L, so this is a Nitro only issue, and an R/T only issue as far as I've been told.
According to the dealer, all of the new R/Ts on their lot make this sound... however on Tuesday night I'm stopping in the be a P.I.T.A again, and have the tech ride along to listen to yet another noise (transmission is making a groan and a bump when downshifting) and while I'm there I'm going to not only have them listen to this noise from outside the car (where it's REALLY loud) rather than the driver's seat with the windows up.
I'm also going to ask that they allow me to ride along in another new R/T and see if in fact it makes the same
noise, and not just a similar one. My whistle has been getting progressively louder... I can now hear it clearly with the windows up and the radio on. Also my fuel mileage seems to be getting worse, and the car seems a tad sluggish. I feel it's a clogged cat, and I want them to really look into it and not just dismiss it as being quote "normal" because some other Nitros make a whistle noise *sometimes* too.
If the other R/T does it, and it's just as loud... I'll back off a bit and wait for Chrysler to give a TSB. Otherwise, if the other R/T only barely does it (or doesn't do it at all) I'll demand they start replacing things to fix it... what you hear in that video is now what I hear from inside with the windows up, and when I taped that the camera was outside right next to where the noise is coming from, so yeah it's louder now.
Yeah I called the 1800 line, and they are next thing to worthless... they yelled at the dealership for not fixing the problem, but at the same time the lady told me the car is "operating as designed"
The dealer and I both got quite a laugh out of that ordeal...