Annoying issue

First of all, let me give you a little introduction of the recent history of my car. When I went to see it, I noticed a noise that I didn't think was normal, but the car was running very well. Another day I took it to the dealer to make a general check-up and an engine compression test. The mechanic said the compression was fine, the spark plugs were healthy too and didn't find any strange noise. I ended up buying the car.

Days later, I had to go visit a mechanic and asked for a second opinion about the noise. He said there was a noise from the accessories belt/pulley but not always and advise me to keep going for a while and replace the part later, when the noise gets more obvious. But I think the noise he was talking about it's not the same I told him.
When I heard this noise more clearly was when I was accelerating, going up a road in 3rd gear at 1500 rpm. Unfortunately I was not recording, but when I arrived at home, I asked for someone to put the engine at 1500rpm while I went around the car and looked in the engine bay for the noise but it didn't appear that time. The car was standing still, though.
I suspected it had something to do with the exhaust system and knowing that the exhaust manifold can crack, I had to inspect it as well as I possibly could but didn't find cracks. One more information, I notice that when I start the car, there's a petrol smell for a moment.

For your judgement, I took photos from the manifold pipes junction and made a video of the car running, cold started.

Had to storage in hubic because it's just sound file. Sorry.


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I took off the heat shield bolts and lifted it so I could see the junction that usually cracks. I also could see the upper side of all pipes and all bolts that attaches it to the engine and everything was ok, I guess. Didn't find any cracks. It's just with that rusty looking and with some colour variations, but that's normal, right?
Even asked to someone start the car while I was looking to the manifold to see if it was leaking smoke somewhere or if there was a notorious noise. Nothing.
can't say for sure as sound recordings can be very poor but to me i would say you have a blowing exhaust, maybe around the flexi pipe and you chains are in need of replacement. do you know when they last got replaced?
The recording sounds different (worse) to what I have listen to when I was recording...
It's what sounds to me either, an exhaust leak. But the dealer mechanic inspected the exhaust and didn't find problems... I hate to have to go fix cars...
About the chain, do you think it's in need? The car has 75000 miles on the clock and I don't have any register or clue that it has been changed.


Senior Member
the astra coupe I bought had done 73k ,came with 16 bent valves and broken chains guides says yes it could do with chains doing , to be safe ,,
sadly a lot of so called mechanic's couldn't diagnose a flat tyre :(

with the age of your chains i would get them replaced. 100,000 miles or 10 years. may have had poor service history?
only use genuine parts with chain kits or you will be changing them again after a few 1000miles:cry:

your pre cat may be blocked or breaking up. only real way to tell if this is the case is to remove the down pipe and have a look.
Shouldn't a blocked pre cat give a warning light on the dash / error? Or if for some reason, I remove the pre cat, will the emissions light come on?
I have the service history of the first 3 years and the last 2. Seems alright. The car in general seems to have been looked after, genuine parts or good brands at least. Maybe the problems are coming up now... I hope not.

But I'm starting to feel unlucky with this car. I just bought it, it looks good and runs fine but it seems to have a lot of (and expensive) issues.
Until now I already had to replace the gearbox / axle rubber bellows (and consequently gearbox oil), brake fluid reservoir cover (little expensive thing) and brake fluid, 4 new tyres and had to do some paint jobs too. And now I probably have some exhaust problem and chain to replace... Got to choose a bank to rob.


Senior Member
2 owners , first owner really looked after it , loads of paperwork , all genuine gm parts , 2nd owner youngish lad , chain guides fell to bits picking it up from pub ,:eek:
age can make chain guide's fail as they are a plastic type.
pre cat can be removed without any problems at all. but you will notice a small increase in power :)

i would not recommend anything but genuine parts for the chains. seen to many fail at very low mileage, as in below 1000 mile's! :eek::eek::eek::eek:
Ok. i will try to find someone who knows this engine to solve this because I had enough of shops that seems to know less than me.
Anyway, an update: I went to an exhaust specialist and the exhaust is fine. If there is a leak, must be in the manifold. In the test drive I did with the technician, he noticed the noise and said it can be a tiny leak but could not inspect the manifold today.
Thank you all. I'll keep in touch with the news.
Well, I haven't found a specialist yet and I doubt I will so I'm thinking about asking to the mechanic/shop that I know for some time now to do the job.
Anyway, I asked for the price of the chain kits at the dealer and I found cheaper on the internet.
For example:

Is this serious? Same material, same kit that costs a lot more at the dealer?

Another question, what about oil pump, water pump and cover gasket? Do you use to replace any of these parts when changing chains?

Edit: The upgraded chain has 3 coloured links, right? If not, it's the old one?
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if that is a gm part then its a great price.
all replacement kits should have coloured links.
the new kit contains a bigger oil spray jet and a better tensioner. it has a dimple on the end not flat.
you will need a new timing cover gasket, and most likely new cam cover seal set.
i don't know what age they changed/revised the kit.
was not done under recall only fix as fail or when chain was replaced.
i had my 2.2 Vectra B from 6 months old in 2001 and had a few other recalls but not for chain kit.
only found out about it when i ordered new kit in 2009 and that still had old tensioner but new spray jet, and was told about update to oil pump at the same time.
I'm back with some news. The chain that was a little loose, according to the mechanic, was the balance chain. I'm not sure if the nozzle was the revised or not, but the tensioner was the old one. Genuine kit installed with revised nozzle and tensioner and around 4300 miles later everything is ok, I guess. Found new "problems" but not concerned to chains.