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Re: Timing Chain Questions....... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Wed, 18 Sep 2002 23:03:08
In Reply to: Timing Chain Questions......., RobertM, Wed, 18 Sep 2002 14:46:08 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Saab engines aren't very quiet, and they're even less so when cold. The timing chain gets blamed a lot because it's scary and expensive. I guess it's human nature that if you're going to fear something's wrong with your car, you figure it's the most expensive part.
Yes, timing chains can make noise. The timing chain has a few guides, and one of these guides is at the top of the engine, right under the valve cover. It dries out over time, and can be easily replaced.
When it comes to timing chains, unless your engine sounds like a coffee can full of silverware rolling down stairs, chances are good your timing chain is just fine. They normally last a very long time. NEVER change a timing chain on sound alone, no matter what the mechanic says. There are easy and relatively inexpensive ways to tell if your timing chain is bad. This method is called looking at it. If you're really worried about the chain, remove the valve cover (chances are the valve cover gasket is leaking by now and needs replacement anyway) and look at the chain. If it's worn, it'll look worn. You can also turn the engine to TDC for cylinder #1 and see if the alignment marks on the cam line up with those on the head. If they do, then the chain isn't worn.
Timing chains tend to rattle, not buzz. But describing sound over the Internet is tricky.
So what's the buzzing? It can be A LOT of things. It could be the chain. Probably not. It could be a sticky valve lifter. An oil change can often help with that. It can be a noisy fuel injector, worn fuel damper, or bad pulley bearing.
Get yourself a couple of feet of hose - I use some old garden hose, but any hose about 3/4 inch to 1 inch in diameter works - and hold one end to your ear. Move the other end CAREFULLY around the engine when it's noisy. It's a cheap stethescope that will quickly isolate the sound. If the sound is coming from the very top of the engine by the firewall, that could be the timing chain, but more likely a sticky lifter. If it's truly a buzz, that's too fast for the timing chain, or even a fuel injector. I'd put my money on a bad idler pulley bearing, buzzing AIC valve, or even a buzzing APC valve.
Once you've identified the buzz, go from there. If it's a pulley, that's Natures' Way of saying it's time for a new pulley. If it's the AIC or APC valve, unless you're seeing other engine problems, leave it be.
Timing chain? Most probably not.
Good luck!
posted by 12.79.33...
, Wed, 18 Sep 2002 23:03:08 <-- Viewing This Message
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