Ok guys just before i had my car serviced my car was developing an engine rattle sounded like the lifters/tappets, but only happend on cold starts, if i restarted my car or waited it would disappear, so im hoping theres a cleaning process similiar to this (http://www.aussiemagna.com/forums/showthread.php?t=43017&page=3) <- for the 3.5 l (or if that can be done for the 3.5 litre to let me know, im no good with cars, but dad can do it for me)

but also in saying that the guys @ midas said my rocker cover seals were leaking, not a concern atm but worth checking out next service, would that have anything to do with it?
and if so, how much is it to get that sorted normally?

i just want the problem gone so any help would be fantastic

In general when the lash adjusters start to de pressurise when the engine is off, this is the first sign that they are getting blocked.

So many people replace them and do not properly clean out the rocker gear, this will cause them to rattle again in short time, believe me, i have been caught out myself with this.

You can try engine flush, try Penrite HR15 as this will be your best chance, some oils just do not cut it in the Magna Engines but at the end of the day, when the little valve inside them is no longer holding out, it is time for them to go into retirement