I noticed a rattling sound when turning on the car and at around 2-3k RPM. Took the valve covers off and although the main timing chain and guides all seem good, the drivers side secondary timing chain seems to have some slack while the passenger side does not. Could just be coincidence, but using a screwdriver as a stethoscope it did sound like the noise was coming directly from the drivers side valve cover. Is it normal for one side's secondary timing chain to have slack?