2015 Forester - whine/Rough at specific RPM

[MoneyJohn]

Hello folks,

This vehicle as about 40K on the odometer bought new. At 1500rpm, the engine whines or feels rough. I can't explain it well. I can feel vibrations in the accelerator pedal but overall vibrations are felt all over the vehicle. Anything above or below 1500 rpm, no feeling of such vibration/engine running rough.

This feeling has been going on for a while but was not as pronounced. I don't drive this vehicle often. Maybe that is the reason I am feeling it more pronounced. There is no change in the way the vehicle drives, just this rough whine irritates me.

What can this be? Any educated guesses?

Thanks in advance.

Edit: This is a 2.5 liter engine, not a turbo

 

[mclasser]

Possibly CVT related?

 

[Fotoflame]

Hello there. I own a 2015 Forester with the 2.5 as well. Without sitting in the car and experiencing what you're hearing/feeling, it's hard to tell what's going on. I will say that the FB25 engine is pretty noisy. It's not the most refined so if you don't drive it often maybe that's something you're not used to. Also, the vibrations you're feeling could be the CVT trying to hunt for the right gear ratio. If someone else drives the car mostly, it has adapted to that driver's habits. You driving it with different habits could be throwing the CVT into a fit making it hunt for a different ratio causing vibration. The CVT does get confused sometimes on mine trying to find the right ratio.

Also, these engines also tend to drink oil. Mine takes 1 quart at least between 6000 mile OCI's. Some owners report using more. Keep an eye on that oil level.

 

[Job]

Does the engine and drive train have 5 year 60k warranty? Search for the problem it is one of the only things I feel the internet is good for.
I had a click in my drive train was thinking all sorts of parts needed. Searched and found many others had the same thing. I torqued the axle nut to the 185 required and problem gone, zero dollars. Got to use my new Husky torque wrench.

 

[MoneyJohn]

Originally Posted by mclasser
Possibly CVT related?

I don't have anything to prove that it is not CVT related, at the same time, the whine/vibration goes away if I speed up or slow down and get RPM below 1500. The speed of the vehicle is irrelevant. At any speed, if I am at 1500rpm, it would whine. Do you still think it is CVT related? I thought RPM would be related to the engine.

Originally Posted by Fotoflame
Also, the vibrations you're feeling could be the CVT trying to hunt for the right gear ratio. If someone else drives the car mostly, it has adapted to that driver's habits.

My wife is the primary driver of the car and she mentions too. She claims that it is getting louder lately so she wanted me to drive for a day that I was making 100-mile trip so I will understand what she is telling me about.
Originally Posted by Fotoflame
Also, these engines also tend to drink oil. Mine takes 1 quart at least between 6000 mile OCI's. Some owners report using more. Keep an eye on that oil level.

Luckily, mine doesn't drink oil (yet). I check oil level every 2 weeks and so far max I have added is a 1/4 quart over the OCI.

Originally Posted by Farnsworth
Does the engine and drive train have 5 year 60k warranty? Search for the problem it is one of the only things I feel the internet is good for.

I have been searching but so far I found nothing.
And as @Fotoflame mentioned, unless someone really drives, it is very difficult to explain the problem. So if others are facing these problems, maybe the term usage is where I am missing to find similar topics.

 

[IveBeenRued]

My Impreza did something very similar and turn out to be a misaligned air box. I fixed it by taking off the ram air duct and then reseating the cover holding in the air filter.

 

[ARCOgraphite]

Originally Posted by IveBeenRued
My Impreza did something very similar and turn out to be a misaligned air box. I fixed it by taking off the ram air duct and then reseating the cover holding in the air filter.

I was just about to mention that. If you get a resonance in the intake tract, it will cause air metering problems at certain rpms.

Make sure the filter is in correctly and the air box tabs are in the lower hinge buckles.
It's not as easy.as it should be - hard to see and feel what going on.

On a sort of related note, I had a intake tube split in the accordion and did'nt see it until i took the whole system apart to inspect each component. That cause d a flat spot or bog when the engine torqued over.
That was a Mazda 6.

Also could have CVT issues, you are not ou of the water there. But you should have received a 100K miles extension

 

[geeman789]

My Impreza has a heat shield / exhaust rattle at EXACTLY 1700 rpm. Below that it's fine, and above is fine too ...

You can hear it, but you can also feel it as well. As others have stated, the engine is not the smoothest and quietest anyway, so I don't worry about it.

 

[SwampSurvivor]

My 2018 has a weird resonance / rattle thing around that RPM. My guess is the exhaust is getting older and just making it more apparent.