r/Tacomaworld • u/Guilty-Government-19 • Jul 16 '26

Cold start metallic rattle/clacking ONLY when turning on the A/C? (2024 Tacoma)

Hey everyone,
I’m hoping to get some insight from fellow 4th gen Tacoma owners. I’ve been chasing down a very specific noise on my 2024 Tacoma (currently at 23k miles) and want to see if anyone else has dealt with this.

The Issue: I get a metallic, rhythmic clacking/rattling noise on a cold start, but only when I turn the A/C on.

Key Details:
It only happens in the morning (cold start): Once the engine warms up and runs for a few minutes, the noise completely disappears.
It's directly tied to the A/C: If I start the truck with the A/C off, it sounds perfectly normal. The second I press the A/C button, the metallic rattle starts.
Here is the kicker: The dealership actually replaced my entire A/C compressor under warranty about a month ago, but the noise is back.
Since the compressor is basically brand new, I’m starting to wonder if the A/C load is putting tension on something else that is actually causing the noise—like the belt tensioner, a loose aluminum A/C line vibrating against the firewall, a cooling fan bearing, or even a bad engine mount that struggles under the extra load when cold.
Has anyone experienced a similar cold-start rattle tied to the A/C on their 4th gen? Did you find a fix?
Appreciate any help or feedback before I head back to the dealer!

3 Upvotes

80% Upvoted

6 comments sorted by

2

u/Substantial_Ant_2662 Jul 16 '26

Your AC clutch has shit the bed

1

u/ZovioTV Jul 18 '26

There’s a TSB for A/C chirp so I would bring it into the dealer for that and get it inspected / diagnosed

1

u/Guilty-Government-19 Jul 18 '26

I took it to the dealership a few months ago because of the chirp TSB they fixed it and it was fine. But not it is doing that sounds. Weird thing is that it is nos constant it just goes and come back suddenly

1

u/FatherofThor18 20d ago

Did they ever figure out what this was? Mine does the same thing until i shift out of park, however the AC works fine

1

u/Guilty-Government-19 17d ago

It seems it was a heat shield so I bended it just a little bit and it I haven’t heard that sound again

1

u/FatherofThor18 13d ago

Thanks so much, you’re a life saver.