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its a ripper isn't it.
Before we go to far on this one. The problem was due to the tech that changed the cam (carried out the techline) missed the fact that you have to remove the 8 rubber O-rings.
This somehow was causing a pressure build-up or something making the noise bla bla bla......
The service foreman ripped off the intake and lifted the valley plate and there they were all 8. He took them out and put everything back together and retested the engine. All's quite now.
40mins work and it was fixed. To bad they had to rip the heads off and put back on. Cost of new gaskets, headbolts etc etc. I know they used new one as they didn't have time to get rid of the original ones.
Anyway I am due to have the car back tomorrow.