2009 Audi A5 - Exhaust valve replacement


I just learned that I need an exhaust valve replacement in cyl2 of my 09 Audi A5 Quattro w/ 124k miles. Can anyone give some idea of the cost involve?

Please give us more details . . .

What problems was the car having?

How was it determined the exhaust valve needed to be replaced?

To be honest, unless I hear a lot more information, I’m kind of questioning the diagnosis. The cylinder head may need a complete valve job, the valve seat(s) may be pitted, and so forth

is the cylinder leakdown acceptable on all other cylinders?

"A “burned valve” is a valve that has overheated and lost its ability to hold a leak-free seal. Valve burning is usually limited to exhaust valves because they run much hotter than intake valves.

The diagnosis of a burned valve is usually the result of a compression test. If a cylinder shows little or no compression, it frequently means the exhaust valve is not sealing. The valve may or may not be actually burnt (melted), but have other physical damage such as cracks or areas where pieces of metal are missing or eroded away from the valve face.

The cure for this condition is to remove the cylinder head, replace the bad valve and reface (or replace) the valve seat. As a rule, the head is usually given a complete valve job at the same time because the rest of the valves and guides probably need attention, too. If one exhaust valve has failed, the rest are probably on the verge of failure if they haven’t already started to leak.

Why Valves Burn
There are several reasons why valves burn. One is normal wear. As an engine accumulates miles, the constant pounding and thermal erosion wears away the metal on the face of the valve and seat. The exhaust valve sheds most of its heat through the seat, so when the face and seat become worn and the area of contact is reduced, the valve starts to run hot. Eventually the buildup of heat weakens the metal and pieces of it start to break or flake away. Once this happens, it forms a hot spot that accelerates the process all the more. The valve begins to leak and compression drops. The result is a weak or dead cylinder and a noticeable drop in engine power, smoothness and performance.

A bad exhaust valve will also increase exhaust emissions significantly because it allows unburned fuel to leak into the exhaust. High hydrocarbon (HC) emissions, therefore, may also be an indicator of a burned valve.

An exhaust valve can also burn if the valve lash closes up for some reason (improper lash adjustment, cam or lifter wear, a bent push rod, worn rocker arm or cam follower, etc.). The lack of lash (clearance) in the valvetrain prevents the valve from closing fully, which causes it to leak compression and overheat.

Valve burning can also be caused by any condition that makes the engine run hot or elevates combustion temperatures. This includes cooling problems, abnormal combustion like detonation or preignition, loss of exhaust gas recirculation (EGR), retarded ignition timing or lean fuel mixtures."

if its really a burnt valve ,the cost would be around $3000 to repair.

Why don’t you ask the shop that diagnosed the burned valve what they would charge?

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No matter if the problem is one valve burned, damaged to a timing belt issue, detonation,
or whatever a full valve job should be performed considering the car is near 11 years old.

Gasoline (regular or premium) can have a serious effect on valves all depending.

The cost can vary greatly depending on a number of factors but it WILL be expensive.


Why ask the shop when you can go on the web and ask people who have no idea where you are or how much other work needs to be done ?