Does this chain sound like it is on the way out?

[willheath]

Hi all. I've been a member for a while, but this is my first post.

I have an X reg, Astra G sri with the Z22SE engine. I bought it when it was 1 year old in 2001. It's had an easy life, now on 61k, mostly with journey's of 7 to 12 miles. Main dealer serviced up to 2008, then after that at a local independent. The main dealer services always included their recommended oil flushes.

Recently the car has been developing a rough idle, particularly when warm. Sometimes the engine just cuts out at idle. It is also hesitant at low revs to the point of sometimes kangarooing a bit. Once it gets to about 2500 rpm it runs smoothly and pulls as it should.

Last week I got an emission system light warning. The fault code was for the EGR valve, so I took that off and freed it up (a few hundred thousand cycles using a computer controlled lab power supply). That cleared the fault code. but sadly did nothing to improve the poor idle.

Reading around on the forum made me wonder if the cam chain could be behind the poor idle. The engine is quite a lot noisier than it was when I bought it. I seem to remember it being so quiet that I accidentally tried to start it while running a couple of times. As far as I know the chains have never been changed, unless perhaps the main dealer did it quietly without telling me.

This is a recording of cold start. (It took two attempts, but that was just because I had done another cold start earlier in the day without driving anywhere. It usually starts first time from cold, but recently has been more reluctant to start when warm). Does this sound like a bad chain? Should I even not risk driving it at the moment? To me it doesn't sound so much like a rattle, just generally noisy, but I would appreciate hearing opinions from more experienced ears.

Thanks in advance

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Chris Butler

 

[vpm]

Sounds like a loose chain to me, the chains on these are prone to jumping teeth due to worn tensioners and worn or broken guides, it involves buying a timing chain kit, balancer chain kit and gaskets. It's also about a four hour job for a pro with the equipment ie lift, locking tools etc. If you are confident enough to tackle it yourself then have a go, there is a guide to it on here somewhere but take you time and be thorough. Be warned though, the kits are not cheap, i used an fai kit off ebay for £116, balancer kits are nearly the same and gasket and aux belt £20-£30.

 

[Dave Gilbert]

Jesus turn it off.......

That sounds horrible, id say new chains are required asap

And I would recommend using GM chain kits, you get all the gaskets and crank oil seal etc.

I know a man who loves to do these chains if you dont want to tackle it yourself

 

[Dave Gilbert]

It mite soynd worse because its in a garage aswell but it doesnt sound good.

I did have a noisy alternator bearing that sounded similar to chain rattle. Mite be worth a look

 

[willheath]

Thanks for the comments.

I got hold of an Op-com to try and get some extra clues. The lowest manifold pressure didn't occur until about 2500 rpm (off-load). Likewise, the 1st lambda sensor didn't start pulsing up and down until about the same engine speed. Below that that it was reading continuously high. This made me think there might be an air leak, or that my EGR fix had failed. It turned out that the latter was the case. With the EGR valve now sorted out, the idle and low rpm running are back to what they should be.

Now running smoothly outside, it sounds a lot better. As was suggested, being inside the garage probably made it sound worse that it was. However, I'm still a little nervous about the chain. It's at 60K on the original and the car was made in 2000. So it seems to be a candidate for chain failure at some point in the not too distant future.

In past years I would have happily tackled it myself, but with my bad back and advancing years I'm not so keen now.

It seems to be running okay at the moment, and I now have some pressing family issues to take care of. Hopefully it will keep going until the new year, when I will see if I can find one of the forum's resident chain experts who would be interested in sorting it out for me.

Thanks again

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Chris Butler

 

[Dave Gilbert]

evocarlos knows the best about chains

 

[Matt]

As above, evocarlos will be your best bet for getting the chain swapped out.