[The Radium King]

search here for actuators or variocam actuators and you should get all the info you need. to summarise, they are the electro-mechanical devices that push on chain tensioner pads that increase/decrease tension on chains that join the inlet and exhaust cams - rpm-based variable cam position - variocam.

the pads are a wear item. as such the car's computer monitors their state of health - cam deviation - anything over +/- 9 degrees triggers a check engine light. if your cel isn't on then then your actuators have not failed completely, as when they do go (in my case, any way) your deviation goes really high - i got -16 degrees. how to check - your mechanic if he has the proper tools can read it, or you can purchase a durametric tool and read it yourself.

it's a flat 6 engine so you have two backs of cams, actuators, etc., so will get two deviation numbers (unless your car is euro market where they only read one bank). that info should tell you what bank is failing. decision time:

replace both banks? if one is failing then the other is suspect. pretty much doubles the price, however. list price $1000 USD per bank just for the part. feeling luck enough to stuff a used one in there? it is a labour intensive job, and doing both banks almost doubles the labour (if the engine stays in the car, anyway).

live with it? when it does go you will get a cel. variocam will stop working so you will be down on power. this is an interference engine, which means that when the piston is at top dead centre, if timing is way off, then valves will hit it (fyi, ims failure causes loss of timing which results in piston/valve interference which is how ims kiills these engines; that and metal gets spewed throughout and is impossible to remove from tiny oil passages). in my experience, with a failed actuator and -16 deviation, timing wasn't off so bad so as to have interference. ie, in my experience total failure of an actuator is not catastropic (as opposed to ims failure).

while you are in there. ie, why did it fail? as already stated, the actual pads that the actuator pushes onto the chains are a wear item. my theory? they wear because they get slapped by the chains on start-up. driving around with excessively worn pads and loose chains means that the actuators are over extended for an excessive period of time and they fail. so, while you are in there, replace the tensioner pads (porsche updated the part because of this problem) the chains, the chain tensioners (porsche updated this part as well) etc. mechanic dropped the engine to do the work? then time for clutch, ims, rms, etc.

in my case, in edmonton and porsche indy, price tag to do work with engine in the car, both banks replacing all worn/updated parts was around $7k Cdn.