GM 2.4 Ecotec Timing Chain Problem Explained
The GM 2.4L Ecotec engine has powered some of GM’s most popular models during the 2010s. From the Chevy Malibu to the Polaris Slingshot, the 2.4 Ecotec can be found in a wide variety of vehicles.
What the 2.4 Ecotec might be most well known for though was its tendency to have timing chain failure. One of the most dreaded issues within an engine, a failed timing chain can lead to irreversible damage down the line if not taken care of immediately.
What is a Timing Chain?
Your engine’s timing chain is what synchronizes the four stages of the engine. The timing chain connects the crankshaft to the camshafts. As the crankshaft spins the timing chain will transfer this rotational enginery to the camshaft or shafts. Some engines have one camshaft while it now has become common for dual camshafts. The engine’s camshaft(s) have lobes that open the internal valves. The timing chain gets its name because it sets “timing” and makes sure events are happening at the same time.
The engine has four stages, intake, pressure, spark, and exhaust. During the intake stage, at the same time, the piston moves downward while air and fuel enter the combustion chamber. The camshaft has to open the intake valves to allow the air to fill the chamber. Next, the piston moves upward. The valves must close so the piston can increase the pressure of the air/fuel mixture inside the cylinder. Once the piston has reached its highest point we have a spark. The spark plug causes a spark to ignite the air/fuel mixture. Finally, we have the exhaust stage. The valves open and lex the exhaust gas exit the cylinder. The timing chain is responsible for the opening and closing of the engine valves at the proper time based on the movement of the piston.
You can imagine how much stress a timing chain faces and the amount of friction generated. Oil is of the utmost importance to the life of a timing chain. The timing chain also has guides and tensioners. The accumulation of these components is referred to as the timing system.
The GM 2.4L Ecotec Engine is known for timing chain issues, but in reality, the culprit of this issue are the tensioners. Just like the tensioner for your serpentine belt, the timing chain has two tensioners that put pressure on the chain to stay connected to the sprocket of the crankshaft and camshaft(s).
If the chain doesn’t maintain connection with the sprockets, it can “jump”. This means the chain becomes disconnected from the sprocket and the sprocket keeps turning. Once the timing chain becomes connected again it is now out of synch because either the crankshaft or the camshaft was able to spin freely while the other did not. Once everything is connected the shafts will be out of phase. This is complicated, but just know the engine’s valves are no longer opening and closing in synch with the piston movement. This means the air and exhaust are not entering and leaving the chamber at the correct time.
How do I Know if my Timing Chain is Bad?
What are the signs of a timing chain issue? You will first notice the engine running rough; typically leading to misfires. The best way to feel this is at idle when the engine is at low RPMs. The end result, the check engine light comes on and you’re not sure what to do next
A timing chain failure can lead to catastrophic issues for your motor. If you feel anything resembling the symptoms, such as misfires, contaminated oil, and trouble starting the engine, you should take your vehicle to a repair facility you trust as soon as possible.
Timing Chain Service at Scott’s U-Save
Let the expert ASE-certified mechanics at Scott’s U-Save in Steger, IL New Lenox, IL, or Schererville, IN diagnose that check engine light. To test for timing chain issues, we will often use a 4-channel scope to map the sequence of the pistons to the valves. What we are doing is checking that timing within the engine matches each other.
When we repair a GM that has a failed timing chain, we will replace the entire timing system. There is a lot of labor required to get into the timing chain because you need to remove the front section of the engine. It’s worth it to pay the extra few hundred in parts to make sure none of them fail in the coming years which would require another $1,000+ repair because you again need to remove the front section of the engine.
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