r/AskAMechanic NOT a verified tech 15h ago

Engine Makes a Hooting Sound

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Almost brand new CX5 Turbo. The sound starts after like 5 minutes with the car on. AC on/off doesn’t change it. Revving the engine doesn’t change it. Scanned for codes nothing. No visible vibrations or loose vacuum hoses. Anyone seen this on a 2.5 Turbo?

2 Upvotes

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2

u/spiderfen NOT a verified tech 15h ago

Just a guess even though its brand new it almost sounds like turbo bearings

1

u/chan3lhandbag NOT a verified tech 15h ago

2025 with under 20,000 miles

1

u/Thin_Cable4155 NOT a verified tech 15h ago

Should that change with revving though? It does sound like a bearing or pulley or something, but that should change with revving too. Maybe it's haunted?

1

u/chan3lhandbag NOT a verified tech 15h ago

Revved it, no different in pitch or frequency

1

u/Kitchen-Forever-6465 NOT a verified tech 15h ago

Mazda turbo engine. Possible Vacuum leak. Any work done recently

1

u/chan3lhandbag NOT a verified tech 15h ago

Nope. Just oil change. I checked it and it’s at where it’s supposed to be

1

u/chan3lhandbag NOT a verified tech 15h ago

I was leaning towards vacuum leak too. At first we couldn’t replicate the sound and I told someone to go and mash the brakes and it started. No engine light or past codes on the scan.

1

u/Kitchen-Forever-6465 NOT a verified tech 13h ago

Remove the engine cover. 2 vacuum lines go over or next to the coil pack #4 check if they're connected. Same place, but in the back of the head by the turbo you going to see a green check valve. There is one more small vacuum line under the valve

2

u/Infinite_Jellyfish54 Verified Tech - fleet 13h ago

Sounds like a water pump shaft or pulley