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Pentastar Engine Sounds?

VictorChampion

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OK, so this is not a "do I have a rod knocking" or anything like that question. I have had three JK's with the Pentastar and don't recall it sounding like this. I hear, very often a sound similar to a compressor filling something with air type of sound for a while and then it shuts off. Mostly on start up, cold or warm. It's not the AC being engaged nor do I think it is the fan as I don't know that I have ever heard the fan kick on at 1200 miles on the clock during summer and now start of fall. All of that to say is that it sounds like maybe a semi airing up brakes kinda sound. I took a video of it but in the garage it really doesn't do it justice in the sense that there are a lot of sounds going on. I don't believe it to be abnormal at all as the intervals seem cycled on/off by something. Yes, I have the normal injector ticks and etc., but this is definitely prevalent over the other engine sounds. Any one have any ideas? Maybe it is the fan on low speed but seems too high pitched to be open air moving around and the fan is not on. Thoughts appreciated. It would best be described as a very strong hiss sound like a tire might make losing air rapidly. Again, I don't feel like it is anything abnormal, I just don't recall it on the JK Pentastars. Thanks in advance.

You can hear it shut off at about the 9 second mark.
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muskynut

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Look for a loose or disconnected vacuum hose. Get a few more ears and eyes on it for help.
 
 



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