Mend > Cars

tapping sound at top of engine?

when you just start the engine the tapping sound is there at the top of engine and when you speed up the tapping speeds up and when slow down that calms down and im wondering what it is . vauxhall corsa 1.2

paul
May 2006

Vauxhall Vauxhall Corsa Vehicles, Cars Engine Speed Sound

paul, before you take the car to a garage make sure you have topped up your engine oil,why? because your tappets are hydrualic tappets that means there is very little or no adjustment in them the pressure of the oil is required to keep the tappets from making a noise however if the wear is to great then there could be damage to the camshaft or tappets themselves in which case if you dont have to much spare cash try your local motorfactors and buy new oilfilter and the heavy synthetic engine oil,[ther is also avery thick additive you can buy to add to your oil] this will make your tappets quieter but get them sorted before the engine does it for you.good luck m8

alanmellor
June 2006

Its the Tappets (Rocker Arms) on your engine. There used for opening and closing the valves. Valve clearances periodically require adjustment as the contact surfaces of both tappet and valve stem wear. Over time, tappets fail and will break. The problem with this is it no longer closes and opens the valves properly. This causes the affected cylinder to constantly misfire, with the car being noticeably slower than it was previously, the idle speed being lower, copious amounts of white smoke rather than the normal low amount of slightly bluish smoke for petrol engines, and black smoke for diesel engines, and the car sometimes shuddering.

On a V8 engine, the failure of one tappet would not be too noticeable unless you were aiming for high acceleration.

On a V6 engine, the failure of one tappet would be noticeable, as the engine would not be as responsive.

On a 4-cylinder engine the failure will be extremely noticeable, with reduced idle speeds, and increased shuddering as the vehicles' engine attempts to keep running with a quarter of its engine power missing.

On many diesel engines the failure of a tappet would cause the affected valve to contact the top of the [piston], causing major damage to both components, and possible damage to the engine block and cylinder head.

Take it to a garage and they can sort it for you.

Steven Graham
May 2006