Early morn­ing rat­tle

Car Mechanics (UK) - - Help! -

A cold morn­ing start in my 2005 Corsa 1.0 re­vealed a rat­tle from the camshaft. The noise dis­ap­pears al­most im­me­di­ately, but the clat­ter from the top end con­firms that some­thing is wrong.

I have been in­formed that a re­pair would en­tail a com­plete top end re­place­ment, in­clud­ing the head. Ap­par­ently the whole as­sem­bly is matched for tol­er­ance, etc, at the point of man­u­fac­ture. On the other hand, Au­to­vaux is able to sup­ply ei­ther shaft, in which case I have been mis­in­formed and a cheaper form of re­pair would be avail­able. How­ever, con­tin­u­ing to use the car while con­sid­er­ing the sit­u­a­tion would prob­a­bly in­crease the wear on the jour­nal and per­haps the hous­ing. WHA Burgess There are two ar­eas that may be caus­ing the noise, one due to the tim­ing chain and the other due to a gap be­tween the camshaft and fol­low­ers. As the noise dis­ap­pears quite quickly af­ter start up this would sug­gest the noise is only ap­par­ent be­fore the full oil pres­sure is at­tained.

This could still be due to ei­ther slack­ness in the tim­ing chain (taken up when the ten­sioner re­ceives oil pres­sure) or else cam fol­low­ers that are drain­ing down. If the camshafts were worn the noise would con­tinue even af­ter the oil pres­sure was up to op­er­at­ing level.

You do not men­tion the mileage on your en­gine, but if the noise is com­ing from the camshaft fol­lower area and not the tim­ing chain, I would con­sider us­ing a lifter-free ad­di­tive to see if this will ease things. It would, of course, take an in­spec­tion to en­sure the camshafts were not worn, but given the de­tails you have sup­plied, I would be sur­prised if this were the case.

If the camshafts are worn, then the camshafts and lifters will need to be re­placed. As this is ob­vi­ously an in­volved job, it would also be worth re­plac­ing the tim­ing chain at the same time to avoid prob­lems in the fu­ture. The camshafts and fol­low­ers can be re­placed with­out chang­ing the cylin­der­head.

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