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Rattle at cold start up - Astra H SRi Z22YH - timing chain tensioner?

Discussion in 'Cam Chains' started by Legoman, August 11, 2017.

  1. Car VIN = W0L0AHL4875127680


    It's winter now when my startup rattle is most noticeable and lasts for the longest on engine startup. After the last oil change with brand new oil+filter, the rattle did indeed go away for a time, but it didn't take all that long to start returning again. Less than a month I reckon. Now, in the height of winter cold it is quite bad and noticeable. The car starts up from stone cold in the morning sounding like a tractor or a diesel for the first 1-2 seconds. There's a very noticeable and agricultural clattering going on under bonnet for a second or two before disappearing again.

    I have described it to my mechanic who has said it is what I thought, a stretched timing chain rattling possibly against the inside of its case until the tensioner moves its piston out far enough under oil pressure to take up the excess slack. My question is, what parts are required to service this timing chain noise on startup?

    I'm a newbie to these engines and my mechanic is not overly familiar with them either. The engine has only done 69,000km and I see from the service interval information, that timing chain services are only recommended at 120,000km for the first one. Given that I've only just done over half that distance so far, am I missing something obvious that could be causing the rattle rather than something wrong with the timing chain or tensioner? The engine is completely bog factory standard Z22YH. There have been no major repairs since new and the only non-genuine item on it is the oil filter. I do the oil changes myself and use locally procured Ryco oil filters. The oil used is Castrol Magnatec 10W-30. Not my choice but it's the oil that's been used in the engine since new from the dealer, so I decided not to change type when I bought it second hand. I would hate to spend all the money on new timing chain + tensioner components, only to have the rattle at cold start come straight back again if it's completely normal that these engines start with this noise like this or if there's a much simpler cause I don't know about.

    Any help from the experts on these engines would be much appreciated before I spend an unnecessarily large amount of money on components I may not need.

    Thanks
     
  2. Thanks a lot for that. Is it normal for the chain rattle to start being noticeable on low milage cars like mine? 120k the recommended service interval but mines only done 69k?

    Are there any other parts I should buy at the same time to get the job done? I'm thinking there's going to be necessary some gaskets+seals and maybe some bolts for the gears? Or are these all included in the kits?

    Can I presume that non-genuine products from places the likes of Thailand made by company names you've never heard of are to be avoided? Is genuine the way to go here?
     
    #3 Legoman, August 12, 2017
    Last edited: August 12, 2017
  3. 42000 miles was the most common failure time for the early timing chains (n)

    those two kits come complete with all bolts, you should not require anything else if you are careful removing the oil pump.

    Avoid pattern chain kits, they can be terrible quality. Plus the links above are cheaper than many pattern kits, so why bother paying more when genuine are available.
     
  4. That would correspond almost exactly with when I started noticing the startup rattle noise in mine. My car was made in February 2007. Would that age qualify it as being an "early timing chain"? By that description can I assume there has been a design change improvement since then such that a replacement fitted now could be expected to last longer?

    What about shaft seals and gaskets? While the whole front of the engine is off, should I not take the opportunity to replace some seals and/or gaskets that are only accessible when all the timing gear guff is off? What gaskets will be required for the covers that have to come off to gain access to the timing chains?

    Yep, fair enough. Not being all that experienced in the ways of GM parts, I shall stick with genuine to start off with.
     
  5. you have the later oil jet, but possibly the earlier tensioner. New chain kits come with the latest parts - upgraded tensioner and bigger oil jet.

    GM state the chains should be replaced every 100,000 miles or ten years. Whichever comes first, so yours are due to be changed.

    Once you have replaced the chain kits change the oil every 10,000 miles (16,000Km) or each year, do not use the oil service interval of 20,000 miles (32,000 Km) this is what can cause the chains to fail.
     
  6. My car's history has the oil being changed every ~15,000km which is what I've kept doing since I bought it second hand. That seems to be the recommended interval here anyway. It's after about that distance the little spanner man pictogram pops up on the instrument cluster at any rate.
     
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