I can hear it through the bottom of the car, near the exhaust headers when it's cold. When it's up to operating temp, it's pretty much gone.

Any clues, guys? Car's been to autocross but never abused. serviced every 5-6k, hot oil flush every 15k.

Manual trans.

I called GM, and they say it's a service bulletin where the head has to come off, due to excessive use of certain silicone compounds during assembly. Which is kinda bull@!#$.

mine does the same, curious as to what it is

Exhaust leak.

If its at the valve cover it could very possibly be the timing chain tensioner as well.

nothing at the valve cover. Noise is specifically loudest at the bottom of the car.

At the same time, I don't smell any gas fumes through the ventilation system like the time my downpipe cracked a bit.

Why exhaust leak though? please advise. Thanks =)

typically a ticking that starts when its cold and goes away with warmth is a leak or oil related.

Id be tempted to jack it up and use the screw driver method to listen for it when its cold.

oh ok. Screw driver method?

GM told me that excess silicone was used during engine assembly, and that some of it break off and get trapped in the oil galleries. It's a head-off job =(

I'm REALLY hoping it's not that.....

Well that could be the case but id try and do the simple less expensive things first.

Id almost put money on it that if you took it into the gm it would come back with the noise and you'd have a much lighter wallet.

Take a screw driver and when its running use it as a stethoscope by putting the metal on a part and the rubber to your ear. It will help you track down exactly where the noise is coming from. You will hear it much louder when youve found the correct spot.

Im pretty sure its one of the two I suggested and im leaning towards the tensioner. Its a very common issue with the eco.

wait, what? Tensioner?

FYI, engine's got less than 60,000miles.

thats where the noise im mine is coming from, maybe ill replace the tensioner the winter

Soooo....It's one of my lifters =(

An ecotec lifter isn't a head off affair.

GM replaced the whole engine under warranty at 68 000 km for a ticking noise. At first it was soft ticking and before they changed the engine it ran like an 85 rabbit diesel. lol

Yah a lifter isnt that bad at all..

you can also try this i did with ohv engine and it worked excellent. follow directions on seafoam for adding to oil to clean gunked up lifters.

We Ecos don't have lifters like the OHV.

We have whats more correctly called followers. When they break seafoam wont help them like it may possibly do on the ohv which uses a hydraulic lifter.

Our are still hydraulic though...

Philly D wrote:We Ecos don't have lifters like the OHV.

We have whats more correctly called followers. When they break seafoam wont help them like it may possibly do on the ohv which uses a hydraulic lifter.

Actually that is incorrect. The Ecos "lifters" are known as hydraulic lash adjusters and what people refer to as "roller rockers" on say the OHV (which they correctly are called) is known as roller followers on the Eco's DOHC setup, also sometimes referred to as finger followers.

The TSB that GM has quoted is in reference to the the lash adjusters oil gallies becoming plugged up which results in the adjuster not pressurizing but it is also not uncommon for the lash adjuster to just go bad and collapse, essentially causes the exact same symptoms for both problems (valve tick).

I agree though ticking that can sound as though it is coming from the valve train (valve tick) or even below the vehicle is often times an exhaust leak or a manifold crack. What makes it worse is that either will resonate through the head when listening with a stethoscope and be difficult to differentiate to an untrained ear. The tick will be rather distinct at a rate of half the speed of engine rotation and once warmed up will go completely away as everything expands and seals the leak. Unfortunately this is nearly an identical sounding tick for a collapsed/sticking lash adjuster that eventually pressurizes. There are a couple ways to to determine if the manifold is leaking. One is to feel for air or look for carbon trails the other requires a 5 gas analyzer which I am assuming you don't have access to. Collapsed adjusters will usually show signs of slapping on the valve stem or the ball of the adjuster itself as it smacks the follower. Under high rev you can actually toss a follower out of its home if the adjuster is not there to take up the slack, same if you were to float a valve.




ASE Master Certified Automotive Technician

I stand corrected ............................and will kick the person that told me that info in the balls!