WARNING-------Ecotec Timing chain rattle

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I checked the tensioners in my two engines, one has the domed cap(2009 Cobalt) one has flat (2007 Saturn).

Autozone shows a part 9374 for both engines and appears to have a flat top. They also have two 'bulletins' for the engine about sludge and how to install.

I have never seen sludge warnings about this engine.

My Cobalt seems to have the newer part, but the top of the tension that shows is very rusty. Could the part need replacing even though it is the newer part?

Are there any videos that show the installation and how to avoid or remove dropping pieces when it is removed?
 
I changed the tensioner on my 06 2.2 because I could clearly hear
a chain noise on start-up. It lasted a second or two and it would disappear abruptly like it was shut off via a light switch. If you don't have this noise I see no reason to change the tensioner and I doubt surface rust on the exposed part of the tensioner will cause any problems.

I just slowly removed the tensioner and didn't have a problem with parts falling into the engine but if it worries you, try this. Remove the valve cover first. Now you can see down into the engine where the chain lays against the chain guide which is backed up by the tensioner. Insert a long tool [A yard-sick would work] down by the chain and push the guide/chain back towards the rear of the car as you slowly remove the tensioner.

Once you have installed the new unit, the yard stick can be used to activate the tensioner by again pushing back on the chain guide. You will feel the tensioner release and start to push the guide towards the front of the car. I used tie wraps to secure the chain to the camshaft sprockets so they couldn't skip a tooth. I did nothing to prevent the chain from skipping a tooth on the crankshaft but this doesn't seem to be necessary.

The valve cover gasket is rubber and I re-used it with a little RTV gasket maker.
 
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What about removing the tensioner without removing the valve cover?

I will try the Cobalt with the door open to see if I hear it. I definitely hear it in the Saturn but I wonder if even the newest type (#3) tensioner will eventually fail. It seems like the Cobalt has gotten a bit noisier this last year.
 
It seems I have read there are issues with the 2.4 but they may be different than the 2.2. It might be good to check.
 
The 2.4 litre engine in a 2010 Malibu uses the same tensioner as the new upgraded tensioner for my 06 2.2 Malibu. GM pn 12608580.

You could probably remove the old tensioner without removing the valve cover and you could install the new tensioner as well. The problem is, the tensioner can only be installed in a retracted and latched condition. The tensioner does not remove the slack form the timing chain in this position. Some people claim that starting the engine in this condition causes the chain to snap against the guide thereby jarring and releasing the latch inside of the tensioner.

GM maintenance instructions call for the removal of the valve and a long rubber tipped tool is used to depress and release the latch within tensioner. I think it's foolish to start an interference engine with no active tensioner on the timing chain, but it's your engine.

Here are some pics and more info.

http://www.chevyhhr.net/forums/how-tutor...e-rattle-46159/
 
It looks like to me that possibly one issue is places are still selling the
type 2' version of the part, which has a spring, while the type 3 version does not?

I read the entire thread on the hhr forum and a number of them said chevy tech's just remove and replace with no problems.

I could see how the chain may jump a tooth if the chain is very old and slack and possibly the sprocket teeth are worn as well but I hope my chain is not so loose with less than 80K miles.

I am planning on removing the newer version from my 09 chevy to see if it is sludged up and stuck. If so uld I just clean with solvent and reinstall? I will order a new type 3 for my Saturn and when I remove the old part I will be standing by with a magnet on a stick parts retriever. I guess if I have to I can remove the valve cover but I am reluctant to disturb the coil packs as I have read people have problems with them sometimes.
 
Both old and new tensioners use hydraulics and a spring. You can see the spring is heavier in the new tensioner on that HHR post. You can try changing just the tensioner without removing the valve cover to activate the tensioner. I found removing the cover and ignition coil was not hard and while the cover is off you can look for damage/wear on the chain guides and the chain and sprockets. Your choice.
 
I noticed one of the posts on the HHR forum mentioned the part came with instructions to 'delpoy' the spring via the timing chain cover. If mine comes with those instructions I will definitely do that.

You are right it might be good to check for damage and if so then a complete timing set might be in order. Otherwise my engines are fairly low mileage and basically trouble free and good power and economy, so it would be worth the trouble.
 
Originally Posted By: Max9219
Hi guys, I ordered the new tensioner from Amazon last month, and here is my two cents after working on my 2.2 liter Ecotec L4, 2007 Cobalt:

When you take the old tensioner out, it's very easy for the timing chain to skip teeth at the crank end because the chain will probably be under tension between the intake cam sprocket and the clockwise-turning crank gear. By taking the tensioner out you are releasing all the tension on the exhaust side, and it only takes a very minor disturbance for the chain to skip teeth as it's pulled toward the intake side over the crank gear. I learned this the hard way.

The only way to be 100% sure that you don't skip time is to take the engine timing (i.e. front) cover off before you change the tensioner, and mark the exact current position of the chain on the crank gear for reference. This is a big pain in the butt however, so if you don't want to do this I would highly recommend the following procedure for no-engine-cover-removal tensioner replacement:

1) Jack up the front passenger side securely and remove the wheel.
2) Remove the plastic splash guard to access the crankshaft pulley (harmonic balancer).
3) Use a 13/16" socket wrench to rotate the crankshaft slightly COUNTER-CLOCKWISE. You only need to rotate just enough to move the chain tension from the intake side to the exhaust side, so do this by feel. You will feel a bit of resistance when any slack has been taken up from the exhaust (tensioner) side.
4) Now that the tension is on the tensioner side, this will actually help in removing the old tensioner. Use a 32mm socket to unscrew the old tensioner. A 1.25" socket will also work. If the socket has trouble getting a grip you can do as I did - have the chamfer cut off your 32mm socket so that it engages immediately. I took mine to a machine shop and they simply cut the chamfered part of the socket off with an angle grinder while the socket was chucked and turning in a lathe. This is not needed for new tensioners which have a much bigger head.
5) Unscrew the old tensioner very carefully, and pull it out gingerly to try and avoid any parts staying behind. If not all the parts come out then put a fairly strong magnet into the tensioner hole to retrieve them. This worked for me. If you are unlucky and tensioner parts fall beyond reach, then you will unfortunately have to start removing some engine covers. I don't think this is likely to happen though.
6) With the tensioner out, don't be doing anything to jar the timing chain or tensioner guide. This just increases the chance of skipping time at the crank end. And this is exactly why I recommend the new tensioner be installed ALREADY EXTENDED (next step). Whacking the chain and tensioner guide with a tool to release the tensioner spring is the last thing you want to do, because the chain does not have enough (and even) tension at this time!
7) Take the new tensioner and press it hard onto a block of wood to release the spring and extend it. Yes, they all have a spring and it's crucial for it to extend. Mine took a couple of tries and a surprising amount of force to unlock, so I'm glad I didn't try to do it from the top with the valve cover off. I know people will say that the tension needs to be set in-place, but it's just a spring people. The spring alone gives enough tension for assembly and cold starts. Supposedly the tensioner will also extend a bit more once the engine is running due to oil pressure.
8) Insert the already-extended tensioner into its hole and screw it back on. When it makes contact with the guide, you may need to push it in at the same time as you screw it in, until the threads catch. Torque to 55 ft-lbs and you're done!

If at any time you think that the timing chain may have skipped teeth at the crank end, don't try to start the engine! You will need to remove the engine front cover and valve cover to check the timing. Since you already have access to the crank pulley, you can try carefully turning the engine over clockwise by hand with your 13/16" socket to check that it turns freely (no piston-valve contact). This is best done with spark plugs and serpentine belt removed plus car in neutral so that the crank turns more easily and you can immediately feel resistance. When in doubt, do the extra work and open the engine front cover and valve cover to check the timing. You can bend valves even when turning by hand. If the engine runs but you now get a P0016 OBD code, then time has slipped slightly at the crank end, hopefully not enough to damage the engine.

Good luck!
Max


this method makes a lot of sense for older cars with high miles that may have the chain stretched already. plus no need to remove the cover (if one removes the old one in one piece). i'm going to order that new tensioner on amazon soon.
 
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