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

[Winterpeg]

There is a thread on the forum regarding a "brief rattle noise on startup " on ecotec engines.Some have thought it was oil filter related.This is wrong.Its a timing chain tensioner issue. There have been numerous tensioner revisions for ecotecs and the latest revision (since about 2009) finally corrects the rattle which is actually a loose chain on startup.Check your tensioner and if the head of it is FLAT then you have an old style. The new one has a raised bump on the head.A few seconds of looseness every time you start will eventually lead to a stretched chain and failure down the road. My vehicle is a 2006 and had one of the older versions which I changed out.There are instructions for doing the change out but BEWARE----the plunger of the old tensioner may spring out when you unscrew it from the block so hold that plunger somehow. Mine sprung out and fell down inside the engine.
I was able to get the parts out with a magnet luckily so beware.

 

[PF52]

I wonder if there is a campaign to replace these? I have an '06 also and I noticed about a year ago it already has one of the new-style tensioners. I'm thinking the dealer installed it on one of my rare visits there (had the trans fluid serviced; gotta love coupons!). Otherwise, replacement is a ten-minute job or less.

 

[FFeng7]

I am curious about this. I have never heard that timing chain tensioner to be a problem on these engines. How difficult is it to replace? How do you know if it is failing? By the start up rattle? I might have to do some research on this topic. Thanks for putting this out, like I said, I had no idea.

 

[PF52]

Originally Posted By: FFeng7
How difficult is it to replace?


Its very easy. Here's a how-to I found in the HHR forum:

http://www.chevyhhr.net/forums/showthread.php?t=46159

 

[Astro14]

Having lived through a few Winnipeg winters, including walking to Grammar School, I am just laughing at the OP's name! Very apropos....

Cheers!

 

[Winterpeg]

First off check your existing tensioner to be sure it is an older style---older style=flat bolt head, new style = bump on bolt head.
Replacement consists of removing the engine covers and intake air cleaner assembly,ignition coils assembly and the valve cover. As I said, when removing the tensioner (unscrewing it)be sure to somehow contain/stop the plunger from spitting components into the cam chain area.Make sure the new tensioner plunger is compressed when screwing it in and then release the plunger by tapping the chain area where the plunger presses against.There are explanations online how to do this.

 

[Winterpeg]

No campaign. The original tensioners on the older ecotecs were so bad they came out
with an upgrade which still did not totally eliminate the problem,still had startup rattle.
Startup rattle causes slight shock every time you start your car but the chain will last a long time--probably at least until the warranty is over.However I thing owners complained enough that they finally came out with the latest good fix.Campaigns cost money so they don't advertise it, you have to rely on honest people who don't want others to go thru grief
at the greedy hands of the automakers unfortunately.

 

[PF52]

Originally Posted By: Winterpeg

There are explanations online how to do this.


There are many explanations online but most do not call for removing the coils and valve cover.

The new tensioner shouldn't require any extra steps to extend the plunger; this is done as soon as you start the engine and it fills with oil.

 

[FFeng7]

Thanks for the replies. I'm going to look at the HHR site and do some more research. My 2005 Cobalt seems to have a very slight rattle when it is fist started. Sounds a lot like a bad anti drain back valve on a oil filter but obviously it does not have a drain back valve anyway. Thanks again!

 

[Winterpeg]

I don't know if you have done one of these yourself but
Enginebuilder Mag has an article and here are 2 lines from the procedure:

19. Install the timing chain tensioner.
Tighten the timing chain tensioner to 55 ft.lbs. (75 Nm).

20. Use a suitable tool with a rubber tip on the end. Feed the tool down through the camshaft drive chain to rest on the timing chain. Then give a sharp jolt diagonally downwards to release the tensioner.

They don't say anything about leave it alone, oil pressure will take care of it. I would rather spend a few minutes removing a valve cover and doing it the right way. In addition
as I said from experience, mine spit parts inside the engine when I removed the old one
so you can take your chances but I wouldn't.

 

[threeputtpar]

From the HHR forum, it appears that the old design tensioner had to be "released" throught the cam cover after it was installed, but not the new one that operates hydraulically off of the engine oil.

 

[Winterpeg]

I did just install the new style tensioner and there is definetly a spring in it just like the old style.There is a hydraulic component to it but trust me, I installed it in the compressed state and had to spring it open by tapping the cam chain.The plunger will pull
out and in while the spring is in the locked state due to a cam inside the tensioner.
It is the spring inside that is released when you tap it, the spring provides most of the tension with the oil as an added buffer.I don't understand taking all the HHR forum quotes as gospel when in fact the guy who did it was lucky when he started his motor the chain probably slapped the tensioner and released it. As I said before take your chances.

 

[NateDN10]

Thanks for the info!

 

[FFeng7]

I have to admit that I am nervous about doing this project. I read on a cobalt forum that the guy who replaced the tensioner on his car did it wrong and the car jumped time. Of course being an interference engine it also bent the intake valves. I am scared that this could happen to my car too. I wonder what the long term effects of not changing the tensioer would be. Obviously, shortened chain life but I am curious to how much shorter? Is it worth it to take it to a mechanic to have them swap the part?

 

[SnPb]

I have a 2009 Cobalt with the 2.2 that developed the startup rattle. At 31K miles the Intake Camshaft Actuator failed. The local Chevy dealership replaced the Actuator under warranty, no questions asked. There hasn't been any startup rattle since then.

 

[Winterpeg]

After hearing a loose chain for a couple of seconds that was enough for me to change it.I live in a cold climate and thus it was worse in the winter.For the $52.00 it cost me it was worth the peace of mind. I have 100,000 km and plan to keep it till she's done.There is alot of force on that chain. Consider starting and getting up to 1000 rpm almost instantly then tightening.
All I can say is chevy came out with this part for a reason.I don't think you would get a straight answer from a dealer about the life without changing this part,especially if under warranty still.If you have a good flashlight and a long narrow screwdriver to hold the plunger
while unscrewing the tensioner its easy to do. I think not all tensioners spit their guts,some may be varnished enough not to do this.Mine did,probably because lower miles and synthetic oil (there's a plug for syn ).There was absolutely no varnish on mine,it was very clean.

 

[Gabe]

Originally Posted By: Winterpeg
My vehicle is a 2006 and had one of the older versions which I changed out.


I thought it got redesigned in 2005. The new timing kits have a blue/purple links instead of the original silver/gold.

The problem was with the oil flow nozzle; under extended period of idling, the timing chain doesn't get enough oil. Or so I thought.

 

[AMC]

Thanks for the info, my 2002 Sunfire always had a little rattle at start up but I just considered it normal. If the job really is as easy as unscrewing it and installing a new one, I might just have to do this. Does anyone here know the specifics for the 2002 ecotec engine that went inside the 2002 and later sunfire/cavaliers as far as this job is concerned?

 

[Winterpeg]

It has been re designed a couple times, the latest around 2009 which is the one I put in.
There is no rattle now.
The oiling nozzle which is a separate part was changed I think around 2003.

 

[FFeng7]

Thanks for the replies guys. I am going to try and replace the tensioner myself. I ordered one today off of Amazon for 31 dollars. I figured 31 dollars is Mich cheaper than a new timing chain if it fails. I am going to remove the valve cover and try to do it the right way. I have one question though. Should I try and maintain tension on the chain so it does not slip off of the bottom sprocket . I am a little nervous because I really do not want the car to jump time. It runs so good now just a little rattle at start up and I do not want to make it worse by changing this tensioner. I might give it a shot this week. I will keep you guys informed on how it progresses. Also I'll post some pictures of what the valve train looks like. I'm curious myself how 100,000 miles of conventional looks. Except the last change was synthetic that I put in the car when I purchased the vehicle. Thanks fellows!