I had my chain replaced since it was due anyways. I was hoping that the noise was related to the chain and it would go away after the chain was replaced, it didn't. If anything the noise is more prevelant. Except now I sometimes hear it also when the engine is hot, and sometimes when it's cold I won't hear a thing. I'm wondering if this is a signal of impending vacuum or oil pump doom. Has anyone with a 3 litre turbo diesel ever experianced such a noise. It's not a rattle, but a loud shriek that corresponds to oil pressure rising.

Thanks in advance.