So I've noticed in the 30-40 mph range, my engine sounds like it is revving up but the tachometer doesn't change. This seems to happen more while idleing in this speed range and goes away when I go below 30 or above 40 mph. My 2018 Compass doesn't do this all the time, but often enough that is is noticeable. Has anyone else experienced this?
Hello manichextall ignore arudlang they are becoming a Compass fanboy. You could tell him you have a piston hanging out of your engine and he would call it normal operating condition for engine block cooling or something.
All the below assumes your Compass is 4wd and automatic transmission.
I would do a little test to make sure your not picking up on the same noise related to the rear PTU a few of us have. When you hear the noise start do one of the following move the shifter to manual mode,turn off traction/stability control or select 4wd lock. If any of these things makes the noise stop it is related to the rear PTU. If this is the case take it to the dealer hopefully when noise is present. The sound mine makes sounds more like the rear is driving on a steel decked bridge or grooved pavement and the front is not. But some sounds are perceived differently from person to person so you may very well hear it as the engine revving.
Now that being said this 2.4 multiair does make some strange sounds from time to time. I think what many of us are picking up on with engine sounds is the multiair which has a lot of control over the exhaust valves.When the system makes a huge change to the valves operation the change in the sound of the engine is noticeable if your the type of person that picks up on changes in sound easily. I had to do a double take the first couple of times I heard it because it did sound as if the engine RPM changed when the tach was rock steady.
Another sound I picked up on even while test driving our Jeep is sometimes I hear what sounds like parts in the transmission spooling up. This 9sp gearbox is unlike anything else I have driven. It is pretty advanced and has a lot going on in a small unit. I think sometimes when the computer is predicting certain shifts it starts bringing certain parts up to speed so the shift can be matched in RPM. Other shifts like ones carried out with the dog clutches actually require a very fast netral period so those clutches can be properly aligned to complete the shift.
Regardless if it is something bothering you go talk to the sevice department see what they say. <img src="http://www.myjeepcompass.com/forums/images/smilies/icon_smile.gif" border="0" alt="" title="" class="inlineimg" />