Hi, can anyone give me any idea's.When i start my van in the morning, mostly when its cold,it has a distinctive tap, tap ,tap noise coming from the top of the engine. It carries on even after the oil pressure light has gone out.After about 10 sec's it stops.I was thinking it might be a hydraulic lifter.I dont know for certain if my 1986 hiace with a 3y petrol engine has hydraulic lifters.Can anyone tell me and if there is an additive i can use to quieten the noisey lifter.It doesnt always make the noise. Thanks for any help.