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Hi all i have a noise in the engine.
when i am stoped and i raise it to 3500rpm or more on free gear, it begins to grrrrrrrr
but when the engine is pulling the car, the sound only does while changing gear, like when the revs are decelerating
I opened the hood and it seems to be coming somewere from the injectors, intake. that side


some idea of whta is the sound coming from?

regards

Grrrrr is such a broad term
the situation makes me think clutch, but also could be:
1.spunbearing
2.Droped valve
3.a rattling exhaust (nothing to worry about here)
4.the turbo in it's death throws(if you have a turbo car)


Try taking off your valve cover to see if everything looks right.

I'm just giving you ideas, because you you cant really diagnose a written sound over the internet

It might just be your oil pump, if you're talking about a 4G6x style engine. All of them I've ever owned have made a Grrr noise for me when they're cold. I just drive like grandpa until it starts to get warm, almost no throttle, shifting at 2500 RPM.

They came out with helical cut oil pump gears in around 93 or something to relieve the issue.

I am not so worrying about it too because when pulling, no strange sound happen.
The valve cover was never been taken off as it seems. I also dislike to take it off as leaks will come after.

or an advanced timing? is it possible?