Metal ringing noise from oil fill tube

[MrBond]

Hello all,

New to diesel and more specifically Duramax LLY. 2004 GMC 190k miles

Took the oil fill cap off with engine running and you can hear a slight high pitched metal ringing/rattle noise. This is regardless of engine being cold or warm. Any ideas? Would appreciate if anyone could see if they have the same noise. Thank you

 

[1TRIKHD]

So when you put the cap back on does the ringing go away? Bad pulley?

 

[joelykool]

I had this when I replaced my water pump. I think it was due to that. For my old lly

 

[NC-smokinlmm]

Cp3 and water pump are gear driven, could that be what your hearing?

 

[hondarider552]

Every LB7 I've heard like that does the same thing

 

[ikeG]

Every LB7 I've heard like that does the same thing

X2^

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