Loud tapping sound from left side of engine

[Leo71]

Just bought a 2009 Toyota avensis 1.8 valvematic. Drives and runs smoothly but, there's this loud tapping noise coming from the engine when it's idling. Can't hear it when I first start it up, but when I go for a short drive and pull over its tapping/ rattling away quite loudly. Any body experienced this ? Any feedback will be very much appreciated.

[Duggerz]

Do you know the exact area of the source? You can use a piece of plastic pipe as a makeshift stethoscope placing one end in your ear and the other towards the engine. Note keep clear of moving parts such as electric fans which can start without warning! It may also help if you can post audio of the tapping.

[Leo71]

Thanks for the quick response Duggerz. I'll get on it tomorrow and see if I can get a recording. 

[Leo71]

It was serviced by the local Toyota dealer in February. I did my first oil level check this morning and noticed that it was reading at least an inch over max on the dipstick.Could this be causing something.

[Konrad C]

I have the same engine and it has a tapping sound too. If it is in the top left of the engine, it is the vacuum pump, similar to a diesel engine vacuum pump. Due to the nature of the Valvematic engine with the throttle wide open, there is no vacuum created for the brake servo, hence the vacuum pump. Being a petrol engine which is more quiet than a diesel, it is more noticeable. It you take it back to Toyota, they may say the same thing. Notice the rattle does not get louder as the engine revs, as a cam/tappet does. 

I find it hard to get a good reading from the dip stick. I usually check before turn on the engine, when it is cold and not started since over night. The engine hardly need topping up. It sounds like overfill and does not effect the rattle of the vacuum pump. On the subject of oil, I am using"prefered" 0w20 grade as stated in the owners handbook. I do my own oil changes and other service items.

Don't worry about the rattle and get the garage to check the oil level for overfill.   

[Leo71]

Cheers for the reply Konrad. Yeah mine is in the top left of the engine and does go away with revs. You're right about the quietness of the motor and it does make other mechanical noises stand out I suppose. Been to a garage down the road and had a bit of oil extracted through the dipstick pipe with a pump so that's sorted. 

Cheers Bud.