Hey all, hopefully someone can help me with this. Disclaimer: admittedly I am not the most savvy car guy, so apologies if I don't use the most correct terminology, but I am hoping that I can get some help identiftying the source of a grinding noise.

My car is a 2012 Fit Sport, Standard Transmission, approximately 56,000kms. I've owned the car from new. I've also had a work vehicle more or less the entire time I've owned the Fit, so the odometer reading is pretty low. With the exception of the past 2ish years or so it was also parked in a garage most nights. Car sat un-driven for extended periods during the pandemic. No collisions or major part failures/replacements (aside from recalls), just a couple dead batteries over the years. I always replace the oil whenever the lifespan is low (or at least once a year). Last year or so I was doing rotational work, so the car was regularly sitting outside for 2 week periods without being driven. Roads are heavily salted here in Atlantic Canada during the winter. Hopefully thats enough relevant history.

Anyhoo, to the noise: Recently, maybe the last year or so, I've noticed that I can hear a grinding noise under some very specific conditions. I can reliably replicate the sound when decelerating from highway speeds down to road speeds (~100 km/h to ~60 km/h), specifically while going downhill. I hear a grinding nosie coming from the front end somewhere. The sound appears to be unaffected by braking, gear, or clutch position. The frequency of the sound is definitely tied to speed. The overall "pattern" of the noise is a rising/falling grind, like some component that is rotating at a consistent speed, but only a portion of the rotation is the "bad" spot and produces the noise. I generally do NOT hear it at all when driving on flat, or uphill, or if during my drive I never hit high speed.

I had the car in for some winter maintenance maybe a month or so back (oil, tires, check my brakes, etc) and I told the mechanic about the noise, and described it as best as I could. When I came to pick up the car he said that he couldn't replicate it in the way that I described (I'm honestly not 100% sure if it was actually taken out for a test drive), but he did say that the alternator sounded a bit rough when turned by hand, and recommended that it be replaced. Only reason why I didn't jump right on that was that he quoted an OEM Alternator at some figure over $2K, and aftermarket at something less than $1k, which is a pretty big disparity in prices. I wanted to educate myself on alternators before agreeing to anything. I also don't like to replace stuff based on what seemed like a hunch.

So yeah, has anyone experienced a similar noise? Or have any insights? I figured if it was wheel or brake related it would have been found considering I had the tires recently swapped and brakes & whatnot inspected.

Any help is appreciated. Cheers

 

Just a shot in the dark: maybe the heat shield on your exhaust rusted loose and it's rattling around after you brake/ decelerate.

 

^^
That.

Or maybe drive shafts. There is a recall on them, you should be able to get both replaced under warranty.

 

If you have not had the front disc brake pads replaced since new, it could be those needing replacement. Honda built in a small metal scraper that is attached vertically to the inside front brake pads that scrapes on the rotor surface when the pads are worn down to a minimum thickness. This can be overlooked when an inspection is done on the front pads. Your rear brakes are drum brakes and do not have this scraper incorporated into them. Good luck.