Q: I noticed that when I started the engine this morning it was making a ticking/knocking sound for a few minutes. Ignoring this, I drove off and when I switch the engine off about 40 mins later the engine was silent. After the car was sat a few hours, I started it again and it made the same noise although not as loud, which went away when revved and came back when the engine returned to idle. When I finished the journey the engine was silent. BTW, when I got in the car this morning it was covered with frost (had to sit five minutes to clear windscreen) and was -2oC according to the car tempreture readout. Is this normal? The car is a 2003/2004 and has a perfect service history with 40000 miles on the clock. The engine seems to do it all the time when at idle albiet quiter and it seems to be coming from the top of the engine.
A: You need a quart / liter of oil. I think you are hearing the tick-tick of moving valves that are not getting enough oil.. When you rev the engine, the oil flows faster. But at idle, there's not enough oil. Check now, and write back please with additional details. THE VALVE LIFTERS are on top of the engine, under the valve cover. Check your oil, I think you need 2 liters!!!