Said It Here

Grinding sound when turning off a new HVAC unit

A brand new HVAC unit often makes a grinding noise at shutdown that leaves homeowners questioning if it is normal. This unexpected sound creates immediate worry over a fresh installation and leaves owners unsure whether to trust the technician's reassurance or demand a service check.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Called the HVAC tech
  2. 2
    continuing to drive while unsure of the cause
  3. 3
    asking online for sound diagnosis

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/MechanicAdvice1 person · September 2026

im hearing this funny clanking sound and am jot sure if its ok to continue driving. When the car is in neutral its louder but whne i drive it gets quietersource ↗

Dassomi · r/MechanicAdvice · 5 upvotes
r/hvacadvice1 person · September 2026

Got a new 4 ton unit installed a few days ago and when it turns off it makes this grinding sound every time.source ↗

LeBrownJames405 · r/hvacadvice · 1 upvotes

Where this came up

People with this problem also raised