Just noticed that at idle after a trip, my 97XK8 engine generates a "tick tick tick" sound at about twice a second or roughly 2Hz. Mileage on car is about 58,000km or around 36,000miles. As far as I know, the original chain tensioners/timing chains have not been replaced. I got the car 10 months ago with no detailed service record but the condition was pristine. The ticking sound was definitely not present a month ago when the oil & oil filter were changed.

I've heard the same sound before when I owned a 98XJ8L4.0 and the ticks persisted even after changing the upper belt tensioners.

Please advise what that sound is and what measures should be taken. Thanks.

 

The variable valve timing (VVT) solenoids will make an audible ticking sound as they fire. They are on the front of the valve cover, one on each side, with wires going to each.

They don't fire regularly at idle but will fire periodically to keep things lubricated. If they are rapidly firing at idle they may be getting an unwanted signal. You may hear some other unhappy sounds from the valve train area.

Just for fun, locate the 4 wire large black electrical connector at the throttle body (passengers side, back by the firewall) and make absolutely sure it is tight, clean and dry and the wires are seated in the connector itself properly. Mine came loose this week and caused a similar problem. Easy fix.