Noisy Tappets Cars affected: All hydraulic tappet cars (Lancer 1800 RS/GSR, Evo 1-7) Symptom: A noticeable 'ticking' noise from the top of the engine. Usually appears when starting the engine from cold but can persist. Problem and cure: The noise is caused by air being trapped in the Lash Adjuster (Hydraulic Tappet). Normally the high-pressure chamber in the Lash Adjuster should contain oil but due to various reasons (listed below) the oil drains away leaving only air present. This causes the adjuster to become compressed. The compressed adjuster does not take up the clearance between the roller rocker and the cam lobe correctly when the valve is opening meaning a 'ticking' can be heard. It may take a short period for the air to be expelled after starting the engine so some 'ticking' noise is acceptable however, if the noise lasts for a long period or doesn't go away at all then there maybe a problem. Air can be trapped in the adjuster due to several reasons that are listed below: Incorrect grade of oil used (too thin or thick). Old oil (debris in the oil may block an adjuster). If the car is stood for a long period or if it is stood on an incline (the oil will drain from the adjusters). Over filling the engine with oil (if the oil level reaches the crank it may churn air into the oil that will migrate to the lash adjusters). If the tappet noise does not disappear soon after start up (5-10 seconds) then try some mild racing of the engine. Gradually increase the engine speed to 3000rpm (over 30 seconds) and then gradually decrease it back to idle (again over 30 seconds). Repeat this roughly 10 times. If the tappet noise disappears then the air has been expelled from the Lash Adjusters and they are working normally again. It is worth checking your oil level and condition as that maybe the cause of the air entering the Lash Adjusters in the first place. Change your oil if in doubt. Make sure you use the correct grade of oil as going too thick or thin can make matters worse. Mitsubishi quote 10W30 as the correct grade of oil to use. If an oil change makes no difference then the adjusters are either blocked, worn (spring inside becomes weakened) or damaged and will require cleaning or possible replacement. Garages will normally replace them as it is more cost effective than cleaning and usually they will replace the whole set of 16. A competent home mechanic can clean or replace the Lash Adjusters. If in doubt consult your servicing agent. Approximate cost of repair: Oil change = £30-£50 New Lash Adjusters are approximately £20 each inclusive (fitting approx. 2-4 hours depending on the number to replace) Back to question page