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Discussion Starter · #1 ·
Hi guys, my 900TC has been running sweet (at last) after an aray of problems resolved through this forum (thanks). I have even started running it on the expensive "Ultimate petrol" following an interesting thread on fuel which increases my pleasure driving (plenty of turbo).

I have now noticed that there is a lot of rattling noises coming from the head:eek: Do I need to be worried or is it simply a case of getting the mechanic to adjust the tappett gap? could it be the timing chain? the car has done 137,000ks.

900TC 89 16v

Thanks
 

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Replace the timing chain tensioner: Mine was bad, and I have heard that SAAB work shops replaces alot of them!
 

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You have hydraulic tappets on your car, so there is not a 'gap' to adjust. I had a similar issue with mine and managed to resolve much of it by removing and cleaning the timing chain adjuster. There is a good article on this on one of the forums (sorry, not sure which one). The adjuster on mine was clogged up and it was simply a case of removing and carefully cleaning, oiling up again with engine oil and replacing. (please note the correct way of resetting prior to insertion). I understand replacing the timing tensioner mechanism is an engine out job, so try everything else first.

Although not perfect, it did make quite a difference.

Other options include cleaning the inner (black) cam bearing bolts that feed oil to the hydraulic tappets. These have grooved oilways that can get clogged. But as always, regular oil changes always help. If the noise is more ticking, you could have a failing tappet. You would need to identify which one(s) and replace it/them.

Hope this helps.
 

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Discussion Starter · #6 ·
Thanks Guys, as usual a mountain of information. I will have a look at the tensioner this weekend and replace it if it looks iffy.

There is a bit of clicking, how would I be able to see if I have a tappet on the way out?
 

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Clicking may well just be the normal fuel injection noise (is quite loud). Check if the clicking is coming from the valve cover area or slightly above by the injectors. Some clicking from the tappets when you first start is OK. Just depends on how fussy you are. Plenty of threads on hydraulic tappets.
 

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Discussion Starter · #8 ·
Thanks guys. reading the recent thread where the timing chain has snapped, I think I ought to double check the chain. Are there any threads to show me how to replace the chain?
 

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If its the same rattle mine got a little while ago it's the tensioner which is easy to get to. But replacing the chain..well obviously thats a bigger job than just changing the tensioner. I'd be tempted to (and this is just me) change the tensioner if you think that's it and then leave it at that for the moment.... then again I don't know what the replacement life cycle is for a C900 timing chain. Do you know the maintenance history of the car?

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If you're under the bonnet anyway, slip the belts of the altenator and water pump and crank / rev the engine - quickly, because without the belts you're not pumping water (and you'll over heat and blow your head gasket) nor will you be charging the battery.

Do this to check that you haven't got a bad altenator or w/pump. I've heard that a failed water pump main bearing goes clatter clack clatter clack... worth checking, as the sound can be disturbing, but a cheap fix - in comparison with big ends or a main engine bearing, that are EXPENSIVE!

If you've got the tensioner out, don't loose any of the internal bits, and remeber to re-torque right. Beg, borrow or steal a 1/2" drive torque wrench. I decided to get one in the end (£25 / $40 or so for a cheap and cheerful one. ££££$$$$$ for a pro/shop grade one... endless uses)

You could try tightening up the bolts on your exhaust manafold too, while you're at it. You never know!
 
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