Re: Mystery 'growling' noise at about 1600 RPM. (archive)

My 95 makes the same noise, kind of marble like, but mine is strongest at about 2500 rpm. Its the Vanos. Some make more noise than others. You can try having that replaced, along with the tensioner, but it sounds like you already did the tensioner.

Like I said, some M3s are worse than others, but they all make the same noise. Mine is too loud for my liking, but its been apart and the 'BMW only' shop that works on my car said there is nothing wrong with it, and didnt recommend changing it.

///Mike

Hi all. I've been revisited by an ongoing mystery since I purchased my '95 E36 M3. When the engine is warm, under light throttle, at about 1600 RPM, there is a very noticable 'growling' noise coming from the engine. ONLY at that engine speed. Hard throttle, you don't hear it, rpm's go by too fast;^)
My mechanic took a stethoscope to the valve cover and found the noise to be coming from the cam sprockets, or that area, at least. He could even put his fingers on the valve cover and feel a vibration when the engine was at that speed. First, he thought the hydraulic chain tensioner went bad. Replaced it, didn't stop the noise. Called a buddy of his at a dealership, said he's heard of this problem. Was told the bad tensioner was coming to a resting state too soon, allowed too much slop in timing chain. Soooo... Replaced timing chain, and both cam sprockets. Noise wasn't completely gone, but much much better. A few months later....
Fast forward to the present. It snuck up on me, but the noise is back!! No oil smoke, no puddles, no oil stains on the engine, no red lights on the dash, computer not complaining about it, no stalling or couging from the engine. Plenty of oil. Motor runs very strong. What could it be???
Could the oil pump be going bad? Could it be starving the engine at that speed? Any advice would be appreciated. Sorry for the long lenght of this message.

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