[A930Rocket]

Last month, when I was driving back from Roebling Road, I thought I heard a tapping noise. The next day, I took a listen and when I gave it just a little bit of gas at about 2100 RPM, it made a tapping sound. It did this whether parked or driving.

The engine runs and drives great. I’m told the chains and ramps are bulletproof.

I could not isolate the noise to a specific area, so I removed the belts and the noise was still there. That eliminated all the tensioners, idlers and water pump.

With 178K on the clock, I replaced the side chain tensioner and that seem to help a little bit, by raising the rpm to 2600 rpm, before the noise started. A rebuilt vanos from Dr. Vanos didn’t help. The upper chain, tensioner and guide looked normal.

Thinking it might be a collapsed lifter, I did the old shadetree mechanics trick and ran some ATF in the engine oil, but no difference. After changing the oil and filter, I did not find any metallic parts in the pleats, but I did see small, dark debris. There was nothing in the oil filter housing.

From about 2600 RPM to 3300 RPM, as a feather the gas, I can hear the noise. As the RPMs go up and I feather the gas, I don’t hear it.

So, E46 fans, what do you think… timing chain lifters, or?
Has anyone done either to their E46?