I am getting a howling noise from the front left of engine side when driving on the highway and pressing the gas. The noise can only be heard when I press on the gas on the highway. Driving city doesnt cause it, and if I don't accelerate on the highway no noise is generated.

Any idea what it could be? I am afraid its another repair job. Recently for thermostat done.

 

Elaborate on this; because this doesn't sound dependently on speed of the car, but the applied load to the engine based on throttle input.

Have you checked for loose intake components under the hood?

- Erik

 

Intake would be my first guess too - the OEM air intake pulls in from the left (assuming you're inside the car.) It runs from just beside the driver's side headlight. Your highway revs would be high enough to get the turbo sucking air in; and combined with the ambient airflow from driving at speed it could be hitting something just right to make the howl.

 

Yes it is a MCS. I have checked the inside and dont see anything wrong. Is there a way to fix this?

I am also getting a grinding noise when driving at lower RPMs. So if I am on 3rd gear and RPS is near 2000, I can hear a grinding noise. Is this something to be worried about. Recently I inserted the NM Torque arm , could that cause it ?

 

Depends if there's actually something wrong.
You've only provided us with a vague description of a noise with little details surrounding it.

Again, more details needed.
Is it only in gear? Have you placed it in neutral to see if the same noise exists?
Where is the grinding coming from? Powertrain? Drivetrain? You need to provide more info for us to assist.

No, that's a basic non-moving part; installing that would NOT cause the concerns you mentioned.

- Erik

 

It only happens when I am in gears.

The noise is more of a whizzing noise on the highway when I press on the accelerator.

 

You mention a whizzing noise. Possibly the blow off valve stuck.
It's on the driver's side.
Any change in car attitude (performance) or CEL's?

 

I figured out the howling / whizzing noise. It is the valve that takes air from the outside. It wasn't properly clamped in and that was causing in. I clamped it in and now the noise has decreased though not completely disappeared.

The grinding must be in the gear box. do you guys get the grinding too? Lets say you are in 3rd gear and RPM is 2000? When I accelerate and reach RPM 3000, the grinding noise is gone.

 

No.
Grind... versus a metallic rattle?

If a gear is grinding, it'll grind all through the RPM band; it won't be variable based on engine RPM.
You have a different problem, and it's not transmission related based on your insufficient details.

- Erik

 

You can "grind" the gears when shifting if the clutch is not fully disengaged...but if you truly have a grinding in your transmission when driving, you have a major problem and you will be broken down on the side of the road soon. Take it to a competent mechanic and have him drive it.

 

I am going to record a video and try and post it in here.