timing chain question

rsarnol

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I have an 05 cobalt 2dr manual, total stock 124 k miles. I loaned the car to a family member and as a favor she took it for inspection. mechanic mentioned a noise I had never heard so maybe it just started but he said its the guides for the timing chain. Claimed common prob with ecotecs and theyre plastic and break down and if I dont fix it will jump time and ruin engine. I ran the car and after about 15-20 minutes you can hear what sounds like the chain slapping. I tore the valve cover and cam sprocket covers off and the chain has a very little bit of slack but the guides all appear to be fine. My thoughts are that the tensioner would be the obvious culprit, the guides dont really provide tension right, they just guide chain. I've been browsing forums all day and can't find a single mention of guides failing and I don't wanna replace something that isnt broken.
 
Typically at 124K if you hear noise you replace the tensioner, the guides and the chain.
 
I agree with Zora. And since you've already got it open, just go ahead and do it. That way, you won't have to fool with it again for another 100,000 miles.
 
Originally my thoughts were to get a whole kit and replace everything also but unfortunately its a money issue right now and I was hoping to replace tensioner and maybe it would hold off for couple weeks until I can replace everything. Ive never had timing issues so I don't know if I can run it like it is safely until my next pay or just do tensioner now to hold me over. Plus I'd had really bad issues with the mechanic who did the diagnosis an just don't trust him.
 
But you heard the noise also so why is it an issue of trusting the mechanic? It's pointless to do a half job, did you even price out the parts?
 
My 05 Cobalt had no noise whatsoever coming from it and went to start it one afternoon AFTER a fresh oil change and it putted a few times and died. Would not start.

After thinking about it I did a compression check and had no compression. ALL intake valves were bent.

Engine had 168K on it with frequent oil changes. What I found is that the Ecotec engine weather it be a 2.0, 2.2, or 2.4, ALL need both timing chains, all sprockets, tensioners and the water pump (which is driven by the timing chains) changed at 100K miles to avoid doing almost $1,000 worth of damage to the valve train and engine.

I decided to have the entire engine rebuilt at $1,700 because the parts to do the timing chain myself were almost $500. Then there was the cost to repair the heads which was $450. With the incidental parts and labor it was $1,100 just to get a 168K engine to run again. Another $600 was a no brainer. I now have to drive the wheels off this thing to get my money out of it. And I almost forgot....I pulled the engine myself...Then I had to put it back in....12 hours labor @ $100/hr a pro might do it in less time but really....

Not to worry, I have a granddaughter getting ready to learn to drive.....Prime opportunity !
 
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I know that this is a late response however, someone else may benefit.
 
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