GMC 6.2 Engine (L87): Problems, Longevity, And Specs

There have been different GMC 6.2 small block engines over the years. Its current iteration with the L87 model designation is widely used to power a range of pickup trucks and SUVs under the GM umbrella of companies.

The present version of the GMC 6.2 L87 engine is the upgraded version of the L86 with the same displacement but with better compression figures and higher outputs. Some problems in the previous version have been addressed but new ones have also sprouted along the way.

In this article, we will review the issues commonly found in the engine, its longevity, and specs to help you familiarize yourself with it if you are a new owner or still planning to buy a vehicle equipped with it.

Key features and my opinion about the engine

• Production years:2014-now
• Average lifespan of L87:250,000-280,000 miles
• Fuel supply type:direct injection
• Power range:420 hp
• Fuel efficiency:bad
• Engine block material:aluminum
• Engine reliability score:high
• The most common problems:lifter failure, spontaneous stalling, carbon buildup on intake valves, oil consumption.

General Problems with the GMC 6.2 Engine

According to various reports and reviews about the GMC 6.2 L87 engine, it is prone to the following issues:

1. Engine Stalling When Turning

One problem that the GMC 6.2 engine is known for is its chance to shut off when the driver attempts to make a hard turn on the left or right. Some who have experienced it say that it mostly happens upon returning the steering wheel into a straight position after a wide left.

People who are familiar with this issue blame it on corrosion on the ground connection of vehicles equipped with the engine. They say that this condition prevents the adequate flow of voltage to complete the circuit between the turn signal and the fuel pump relay component.

As a result, the fuel pump is turned off by the fuel pump relay because it can't receive a suitable return channel. The corroded connection transmits just enough electricity to enable the fuel pump relay to work after the driver stops utilizing the left turn signal, and during this time, the risk of engine stalling gets relatively high.

The best way around this issue is to replace the corroded part, which is normally the bolt or nut, with one that is treated to deliver better conductivity and provide better resistance to rust. It is also possible to clean the corroded parts using a wire brush and coat them with dielectric grease for extra protection if the contamination is only minor.

2. Breakage of the Wrist Pin Holding the Pistons

The wrist pin is a cylindrical shaft that connects the piston to the connecting rod. The wrist pin is important because it transfers the force of the piston moving up and down to the connecting rod, which in turn moves the crankshaft. If the wrist pin breaks, the worst that could happen is the engine stalling.

If the wrist pin holding the pistons of the GMC 6.2 engine is starting to break, there are a few potential symptoms that could occur. The engine may begin to run roughly and have decreased power. There may also be oil leaking from the engine or knocking noises during its operation.

The likely causes of this issue include wear and tear on the engine, improper installation of the piston, or damage to the connecting rod. The solutions to this problem may include replacing the damaged parts, recalibrating the piston, or repairing any damage to the connecting rod.

In situations where the problem has led to irreparable damage or breakage, the parts that commonly need to be replaced as a result of this include the piston, connecting rod, and bearings.

3. Crank Damage

It turns out that the GMC 6.2 engine also has a big risk of suffering from crank damage. This is due to its tendency to produce excessive heat when operating.

The crankshaft is a metal rod that is connected to the engine. It is responsible for converting the linear motion of the pistons into rotational motion, which is what powers the car. If the crankshaft is damaged, it will not be able to properly convert the motion of the pistons, which will cause the car to run poorly or not at all.

The possible causes of this problem include a faulty thermostat, radiator leaks, or a cooling system that is not functioning properly. The possible solutions include replacing the thermostat, repairing the radiator leak, or flushing the cooling system.

If the damage to the crankshaft is severe, it may need to be replaced as well.

4. Fault in the Hydraulic Valve Lifters

The hydraulic valve lifters are responsible for maintaining the proper clearance between the valve stem and the rocker arm. The lifters also keep the valves seated during combustion.

The GMC 6.2 engine is known to have issues with its hydraulic lifters. The main symptom of this problem is a ticking noise coming from the engine. This noise is caused by the lifters not getting enough oil, which causes them to tick as they rub against the valves.

The probable causes of this problem include an oil leak, a dirty oil filter, or low oil levels in the engine. The fixes for this problem include replacing the oil filter, topping off the oil levels, or repairing any leaks. In some cases, the hydraulic lifters may be damaged beyond repair and will need to be replaced. This can be a costly repair, but it is necessary in order to keep the engine running properly.

5. ECU Troubles

The GMC 6.2 engine is susceptible to a variety of ECU problems, too, which can manifest in many ways. Common symptoms include the engine stalling or running rough, unexpected changes in engine speed, the check engine light coming on, and varying fault codes.

There are a number of possible causes for these problems, including issues with the wiring, sensors, or ECU itself. In some cases, simply cleaning or replacing the damaged or corroded wire can solve the issue. Replacing a faulty sensor may also be necessary if they have been fouled. If the ECU is damaged beyond repair, it will need to be replaced.

In some cases, irreparable damage to the ECU may occur. This can result in parts of the engine becoming locked up, potentially causing extensive damage. Replacing the ECU in this situation is the only solution. However, if the software of the ECU is the only thing triggering the error, flashing or resetting may be the key to your troubles.

GMC 6.2 Engine Longevity

The durability of the GMC 6.2 engine together with its transmission has been verified to last over 250,000 miles based on the actual tests. The power unit can survive an average of 10 to 20 or even more.

However, it should be noted that the numbers come with the condition that proper maintenance and service intervals are followed. Likewise, it comes with the assumption that problems at their initial stages are addressed without further delay.

Key Specs of the GMC 6.2 L87 Engine

The latest GMC 6.2 engine, otherwise known for its L87 designation, was first introduced in the 2019 Chevrolet Silverado 1500 pickup truck, and it's still used by the present models of the Cadillac Escalade full-size luxury SUV, Chevrolet Silverado 1500 pickup truck, Chevrolet Suburban large family SUV, Chevrolet Tahoe full-size SUV, GMC Sierra 1500 light-duty pickup truck, GMC Yukon full-size passenger SUV, and GMC Yukon XL full-size passenger SUV.

The L87 is a V8 unit that utilizes an overhead valve (OHV) and push-rod design. The naturally-aspirated engine belongs to the EcoTec3 family of GM engines. Its utilization of cast aluminum for the block and head provides it the benefit of being lightweight from the standpoint of usage, which results in better fuel efficiency while ensuring its durability.

The GMC 6.2 offers a displacement of 376 cu. in., a bore of 4.065 inches, and a stroke of 3.622 inches. It has a high compression ratio of 11.5:1, which means that it has better thermal efficiency than before because it promotes more mechanical energy from a given amount of air-fuel combination in the system.

The power unit possesses a redline of 6,000 rpm. In its existing applications in vehicles, it is configured to deliver from 313 hp at 5,600 rpm and 624 lb-ft of torque at 4,100 rpm.

Conclusion

Overall, the GMC 6.2 (L87) is a reliable engine, that's why it has been chosen to power up the large vehicles of Cadillac, Chevy, and GMC. At its best and with regular professional servicing, it can last over 250,000 miles or decades of use before requiring a rebuild or replacement.

The numbers can be lessened significantly though if the problems usually associated with the engine are not addressed in a timely manner. Among the most common problems found in the power unit include stalling when turning, breakage of the wrist pin holding the pistons, crank damage, hydraulic lifter valve fault, and several ECU-related error codes.

Therefore, if you are experiencing any of these symptoms enumerated here, it is important to have your vehicle checked by a qualified mechanic as soon as possible. Ignoring the problem can lead to further damage, and may even render the engine unusable.