Are you planning to purchase a used Chevy Colorado with the 2.9L engine and want to learn more about the GM 2.9L engine problems? We’re sorry to tell you, but that might not be the best idea, and we’ve done our research on why is that.
Proper research is essential when it comes to purchasing a used vehicle. You just don’t want to end up with an unreliable vehicle that will cost you an arm and a leg to fix the issues that it has. And this is why we are here to pinpoint these issues for you.
First, we are going to cover the basic specs of the 2.9L engine, then we are going to elaborate more on the GM 2.9L engine problems and also the applications of this engine. So, let’s dive into the topic.
Basic GM 2.9L Engine Specs
Before we dive into the specs of the 2.9L engine, it is worth noting that this engine is part of the GM Atlas family of engines.
The Atlas family program began in 1995 and these engines were developed for the next generation of mid-size GM trucks and SUVs.
These engines were assembled in Flint, Michigan, as well as in Tonawanda, New York. More specifically, the inline-4 engines like the 2.9L, were assembled in New York.
There were a few varieties of these engines. Namely, inline-4, inline-5, and inline-6.
The engine that we are interested in is the 2.9L. The 2.9L engine is known under the codename LLV, or as Vortec 2900 and was produced between 2009 and 2012.
These are the simple specs of this engine:
- Configuration: inline-4
- Displacement: 178.3 cu (2,921 cc)
- Cylinder bore: 95.5 mm
- Cylinder stroke: 102 mm
- Cylinder head: DOHC
- Redline: 6,300 rpm
- Power Output: 185 hp (138 kW)
- Torque Output: 190 lb-ft (258 N-m)
Common GM 2.9L Engine Problems
Common GM 2.9L engine problems include:
- The Throttle Body Requires Cleaning
- Upstream O2 Sensor Failures
- MAP Sensor Failures
- Spark Plug & Coil Failures
- Engine Valve Failures
- Timing Chain Problems
- Exhaust Manifold Cracks
- Serpentine Belt Tensioner Failures
We briefly listed the common GM 2.9L engine problems, now let’s further elaborate on these problems in-depth and see when and how they appear, as well as the symptoms these problems produce.
Throttle Body Problems
Issues with the throttle body of the 2.9L engine were noted. The throttle body is a special component that is located in front of the intake.
This component feeds the engine with air in order for it to work properly. Unfortunately, these throttle bodies were reported to fail.
Most notably because of carbon deposits. The carbon deposits stick to the throttle body and they will eventually foul the component.
There is a possibility that you remove the throttle body and clean it with carb cleaner. This is possible if there are small deposits.
But if the throttle body is completely covered with carbon, the only way around this problem will be to replace it with a new unit.
Symptoms associated with this problem will be the check engine light, engine misfires, lack of power, and problems with the engine idle.
Upstream O2 Sensor Failures
Upstream O2 sensor failures are also common on these 2.9L engines. So, what is an upstream O2 sensor?
The upstream O2 sensor is also known as the air-to-fuel ratio sensor. This sensor helps adjust the air-to-fuel ratio on your truck. This is essential if you want the truck to work normally and not have issues.
It is worth noting that there are two O2 sensors, one is the upstream and one is the downstream.
The upstream as we noted helps adjust the A/F ratio while the second O2 sensor is downstream, this sensor is mounted after the catalytic converter.
When the upstream sensor fails, you will have a check engine light, poor fuel economy, rotten egg smell, hesitation, black smoke from the exhaust, and limp mode.
The solution to this is to replace the component with a new one and the problem will go away.
MAP Sensor Failures
Problems with the MAP sensor on the GM 2.9L engine were also noted. But what is a MAP sensor in the first place?
A MAP sensor is a manifold absolute pressure sensor. This sensor is installed on the intake manifold and has the simple task to monitor the pressure inside of the intake.
By doing so, this MAP sensor helps regulate the air-to-fuel ratio and helps the engine work correctly.
This sensor, just like the MAF, is crucial when it comes to the engine. What happens on the Chevy Colorado is that there are more than a few of these failures on these specific sensors.
Sometimes the sensor fails and sometimes the harness goes bad. So, the sensor harness has to be rewired or replaced.
Luckily, replacing it is not difficult or expensive. Symptoms of this sensor are poor fuel economy, check engine light and rough engine work.
Spark Plug & Coil Failures
Spark plug and coil failures were also noted on this engine. This happens and is a completely normal thing since these are disposable components with service life.
Once you reach 60,000 miles or so. There is a high possibility that you will have to replace these components in your car.
Whenever these components fail, you will notice the check engine light, engine misfires, rough engine idle, low engine power, and inability to start the engine.
Engine Valve Failures
Another very common problem with this engine is an issue with the engine valves. The valves on some of the cylinders can leak.
When a valve leaks, it leaks compression. So, if there is a leak, you often experience engine misfires on a specific cylinder.
This is mainly caused by bad valves or bad valve stem seals. The solution to this problem is to refurbish the cylinder head and replace the faulty valves.
A lot of owners are struggling with this problem in their Colorado or Canyon. This is why you should do a compression test before you make a purchase.
We recommend this because any type of work that is required includes the removal of the cylinder head and doing a major overhaul. This will cost you at least $1,500. But in most cases it is even more expensive since labor is very pricey nowadays.
Timing Chain Problems
The timing chain can be an issue on these engines. The timing chain is a crucial component that is located behind the timing cover.
Over long use and abuse, this chain will tend to stretch and when it stretches enough, you will start to experience some rattling noises.
If you ignore these noises, you will start to experience engine damage. The chain can jump and the engine valves and pistons will collide, creating massive destruction inside of the cylinder.
If this happens, you will highly likely have to replace the whole engine with a new one. So, don’t ignore the symptoms like the rattling noises coming from behind the timing cover.
Exhaust Manifold Cracks
Another very common problem on these GM engines is the exhaust manifold. The exhaust manifold can crack, or the bolts that are holding the manifold can crack.
This is a common problem when it comes to trucks because trucks are used for work. So, they heat up quite a lot more compared to car exhaust manifolds and go through a lot of heat cycles.
The solution to this problem, if you have cracks on the manifold, is to replace the component with a used one that does not have cracks. Or possibly get a new one, which can be a more expensive option.
Serpentine Belt Tensioner Failures
Serpentine belt tensioner failures were also noted on this engine. So, what is a serpentine belt?
A serpentine belt is a belt that drives the accessories of your engine. This belt is known under many names. Such as alternator belt, accessory belt, or drive belt.
Nevertheless, the tensioner that keeps the tension on this belt tends to fail and this develops a knocking sound. The solution is to replace the tensioner.
Which Models Have The GM 2.9L Engine?
Now let’s take a look at which models include the 2.9L engine. This engine was included in GMC and Chevy trucks but also in one Isuzu model. Which was basically a rebranded Chevy Colorado.
- 2007 – 2012 Chevy Colorado
- 2007 – 2012 GMC Canyon
- 2007 – 2009 Isuzu i-290
What Are The Common Problems With GM 2.9L Engine?
Common problems with this engine include problems with the valves. The valves tend to fail on these and cause misfires, low compression, and other annoying symptoms. The timing chain also tends to go out and start to rattle. In addition to this, the serpentine belt tensioner is another common failure point. Besides that, there are no other serious problems.
Is The GM 2.9L Engine Reliable?
Yes, the 2.9L GM engine is pretty reliable, it should easily last for at least 200,000 miles. But it is worth noting that valves on these engines can fail and cause leaks. This will result in a loss in compression and unexplainable engine check engine light and misfires.