GM 2.4 Ecotec Timing Chain Failure – Causes & Fixes

Austin Parsons

Meet Austin

Austin holds a technical writing degree and has 5 years of experience working as a Technical Product Specialist at BMW. He is an avid car enthusiast who is constantly watching F1, consuming automotive content, racing on his simulator, and working on his Toyota’s and BMW’s. Austin’s technical writing skills, extensive automotive knowledge, and hands-on experience make him an excellent resource for our readers.

The 2.4 Ecotec is one of the most versatile engines used in the GM fleet from 2006 to 2019. In that timeframe, the 2.4L Ecotec was used in everything from midsize SUVs like the GMC Terrain to sportier applications like the Polaris Slingshot. Despite being a very popular and celebrated engine, the 2.4 Ecotec has had its fair share of serious problems, many of which revolve around the timing chain and timing assembly as a whole.

2.4 Ecotec Engine / Credit – Iamjosemom/Wikimedia Commons

The 2.4 Ecotec’s timing chain problems are numerous, with timing chain stretch, timing chain guide failure, and timing chain tensioner issues all affecting the engine. The 2.4L isn’t the only engine in the Ecotec engine family to have timing chain issues either, as other engines like the 2.2L Ecotec are also impacted by similar issues.

In this guide, we will cover the numerous timing chain problems affecting the 2.4L Ecotec. For more information about the 2.4L Ecotec and its other issues, take a look at our 2.4L Ecotec Oil Consumption Guide and our 4 Most Common 2.4L Ecotec Problems Guide.

How Does the 2.4 Ecotec’s Timing Chain Fail?

While it isn’t uncommon for engines to have timing chain issues, most of the time, there is only one cause. In the case of the 3.5L Ecoboost, the cam phasers would cause the timing chain to stretch over time. In the case of the BMW N20, the timing chain guides would disintegrate over time. However, with the 2.4L Ecotec, nearly every timing component is troublesome, from the chain that it uses, to its poor timing chain guide design, to faulty tensioners, the Ecotec’s timing chain problems are numerous and serious. I’ll break down each of the problems individually to better paint the picture in detail.

Timing Chain Guide Failure

The most common cause of timing chain problems on the 2.4L Ecotec has to do with the design of the timing chain tensioner and the upper shoulder bolt that secures it to the cylinder head. The problem starts as the timing chain begins to stretch over time due to the subpar materials used for the chain itself. As the chain gathers slack, it begins to slap around and make contact with surrounding components. 

Over time, as the loose timing chain repeatedly slaps the front timing chain guide, the stress will eventually snap off the upper shoulder bolt or cause it to loosen, stripping the threads and enlarging the mounting hole. When that occurs, the plastic timing chain guide itself breaks into several small pieces that can also become lodged in the oil filter, causing various other issues. Without the timing chain guide, the chain itself gains even more slack, which can lead the chain to jump timing, potentially causing catastrophic engine damage. 

That is an extremely common issue on the 2.4L Ecotec, to the point that there are a ton of redesigned upper shoulder guide bolts for sale in the aftermarket space. 

Timing Chain Tensioner Issues

The 2.4L Ecotec has a very similar issue with its timing chain tensioner as other GM engines including multiple variants of the EcoBoost. The timing chain tensioner is one of the most critical parts of the entire timing assembly, as it keeps tension on the timing chain, preventing it from slipping off of the cam sprockets. Unfortunately, the 2.4L Ecotec’s timing chain tensioner and its design have a number of associated issues.

One of the biggest issues is that, on early LE5 engines, the tensioner is unable to develop sufficient oil pressure fast enough for there to be tension on the timing chain immediately at startup. Since there is slack in the timing chain as the vehicle starts up, the timing chain itself stretches over time. That stretch can potentially lead to engine-killing consequences if not caught fast enough. If the chain develops too much slack, it can jump teeth on the cam sprockets, allowing the pistons to make contact with the valves.

Over the course of the 2.4L Ecotec’s production run, GM revised the timing chain tensioner a number of times. You can easily identify the old tensioner if it has a flat bolt head. The redesigned tensioner has a raised bump on the head and that is the one that you want. To make sure that you’re getting the right one, the revised part number is 12608580.

Failing 2.4L Ecotec Timing Chain Symptoms

  • Loud timing chain rattling/marbles in can noise from under the hood
  • P0016 or P0017 engine fault codes
  • Loss of power/performance
  • Decreased fuel economy
  • Misfires

The main symptoms of timing chain failure on the 2.4L Ecotec correspond directly with the cause of the failure. As I said in the previous sections, there are a number of reasons that timing components fail on the Ecotec. During the early stages of the tensioner failing, you’ll likely begin to hear timing chain rattle when you start the car after it has been sitting for an extended period of time. It is hard to miss, as it sounds like a bunch of marbles have been set loose in the engine bay as soon as you start the car. As the lack of initial lubrication causes the chain to stretch, it begins to make contact with other components, meaning that the sound will continue after the vehicle has been running for a while. 

The more that the timing chain stretches, the more likely it is to trigger a number of engine codes. The main two include P0016 and P0017 codes. Both of those codes relate to camshaft timing, alerting that cam timing is off. If either of those codes are present, there is a pretty good chance that the timing chain tensioner or guide bolt is the culprit. When timing is off to a significant degree, you’ll also experience a loss of power and a decrease in fuel economy.

If the timing chain guide bolt does manage to work its way out of the cylinder head as the result of chain slap, it can cause serious engine damage, to the point where the engine might not even turn over.

How Do You Prevent 2.4 Ecotec Timing Chain Failure?

There are two main ways to prevent timing chain failure on the 2.4 Ecotec. Each addresses both of the main problems with the Ecotec’s timing assembly. Since timing chain guide failure and timing chain tensioner issues are so common on the 2.4L Ecotec, the aftermarket has produced some pretty great solutions for both. 

The first solution is to replace the factory upper timing chain guide shoulder bolt with an updated one. The factory bolt inserts directly into the aluminum cylinder head, which is extremely soft and easy for the bolt itself to work its way out of. Multiple aftermarket companies, including Dorman who produces the most popular replacement option, make stronger and more resilient bolts that screw into the cover plate instead of the cylinder head. That ensures that the bolt doesn’t sheer off if a loose timing chain makes contact with it. Replacing the bolt is as easy as removing the airbox assembly and motor mount, removing the old bolt, and screwing the new bolt in. I’ll leave a video walkthrough below. 

The story is pretty similar for the timing chain tensioner as well. Over the years, as GM discovered that the initial tensioner was faulty, they redesigned the tensioner to hold more oil pressure. The new part number is 12608580, which has a bump on the head bolt. The revised tensioner solves the problems associated with the initial design and prevents excess slack from building up in the timing chain. The installation process is pretty easy for the tensioner too, and the part itself is inexpensive. I’ll leave another install guide below.

2.4L Ecotec Timing Chain Replacement Cost

Preventing timing assembly issues is obviously the better approach than repairing it after the fact. If you’re looking at the symptoms listed above and your car isn’t displaying any of them, you should check your timing chain to see if it has developed any slack, and if it hasn’t, simply replace the original timing chain guide bolt and timing chain tensioner with the revised parts. Most of the Ecotec owners who do that before they encounter timing chain issues never encounter any in the first place.

However, if either the timing chain guide bolt or timing chain tensioner has been damaged, the cost and work required to fix them can be substantial. If the timing chain guide bolt was sheered off in the cylinder head, the head needs to be taken to a machine shop to have the bolt drilled out and a thread insert tapped to accept a new bolt. That can cost in the ballpark of $1,000 alone. However, if that did happen, chances are that the timing chain itself is so stretched that it needs to be replaced, which can cost another $1,000-$1,500 in parts and labor.

The timing chain tensioner is another part of the equation here as well, as it is likely the part that failed in the first place, causing the cascading issues. At most certified GM repair centers, they will likely charge somewhere between $500 and $800 to replace the timing chain tensioner.

If you are handy with a wrench, you can replace the entire timing chain assembly for between $100-$200 if you already have the necessary tools handy. If you are interested in taking on the job yourself, I’ll leave an instructional video below.

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