Chevy 6.6 Gas Problems: A Comprehensive Guide For All Chevy Truck Owners

What are the most common Chevy 6.6 gas problems? Due to the design of this engine, when the truck is cold, it can cause serious problems for consumers. Still, there are some issues with the Chevy 6.6 gas engine, including knocking noise, poor six-speed transmission, and more.

Some people will say that the engine isn’t at par with the options being provided by Ford and Dodge. Conversely, some owners say that it’s good. Here, we will elaborately discuss these problems and their reasons.

Chevy 6.6 Gas Problems

Chevy launched the Chevy 6.6 gas engine after the Duramax engines ran on identical vehicles. This gas engine came with a six-speed automatic transmission. Usually, gas engines are recognized for better acceleration compared to diesel engines.

The Chevy 6.6 gas problems constitute a significant drawback for any vehicle. The problem is that the truck is too heavy, and it does not have enough power to be as quick as other trucks in its class.

You would hope that this would also be the case with the Chevy 6.6 gas engine.

Common ProblemsProbable Reasons
Knocking NoiseValve spring or bad lifters
Reduction in HP & torqueDownshifting
LessTowing CapacityEngine power
Sluggish SpeedNot enough engine power

Below you will find out the Chevrolet 6.6 gas problems in detail.

Knocking Noise

One of the most common chevy 6.6 gas issues is that it has a knocking noise. It is challenging to locate where this noise exactly comes from, but you can only hear it in the park, and neutral. This problem generally starts after oil changes.

It can happen after the first oil change or the second oil change of your vehicle. Some people reported that they had driven 2400 miles and then done their first oil change; the knocking noise started.

Also, some people reported that after driving 6,500 miles and having the second oil change, they have started to hear the knocking sound.

This problem can also happen because of bad lifters and valve springs. A fuel line with a check valve in a Chevy 6.6 gas engine can cause this problem.

Deficiency Of Horsepower & Torque

Another major problem you can find in 2021 chevy 6.6 gas problems is the deficiency of horsepower, torque, and towing weight.

Compared to the Duramax 6.6 turbo-diesel engine, the Chevy 6.6 gas engine has less horsepower, torque, and towing weight.

Based on a 2022 Chevy Silverado HD, the Duramax 6.6 turbo-diesel engine has 445 HP, 910 Lbs.-Ft. of torque, and the highest towing capacity is 36,000 lbs.

Diesel and big block engines make maximum torque at lower revolutions per minute. It is the reason that they are preferred for towing as they have the grunt down low without every downshifting such as the small blocks engines prefer to do.

Towing Capacity

The Chevy 6.6 is a great truck that can haul and tow like the best of them. But with all the horsepower under the hood, you might find your towing needs growing faster than your towing capacity. That’s why Chevy put in their trailer towing option.

Also Read: Chevy Silverado Gear Shifter Not Working- Causes & Solutions

On the other hand, the Chevy 6.6 gas engine on a 2022 Chevy Silverado HD has 401 HP, 464 Lbs.-Ft. of torque, and the highest towing capacity is 17,370 lbs. It can be speculated that the Chevy 6.6 gas engine functions just like any other small block engine.

The Chevy 6.6 towing capacity is 5,000 pounds. That’s more than enough to pull a boat or trailer with your Chevy car. According to GM, it’s also the same weight that a small Chevy can tow.

Sluggish Speed

The 6.6L doesn’t seem to propel as a gasoline engine should. Also, this has also led to multiple unfavorable criticisms since the Superior surge protection, and performance engine operates better on average in this area.

Depending on what you eventually want from your vehicle, that is potentially concerning. On one side of this debate, you have people using it as a routine car, and on the other, you have others using it as a commercial vehicle. Speed is a concern in the everyday vehicle categories.

Poor Transmission Speed

The other issue is that the Chevy 6.6 gas engine doesn’t have the correct transmission to bring the finest out of it in the six-speed option.

Many people debate that the ten-speed transmission will be better than the 6.6/6 speed combo. Besides, some people argue that the ten-speed transmission is very busy as it upshifts and downshifts, making a unique set of issues.

A Helpful Tutorial You May Need!

Frequently Asked Questions (FAQs)

Is the Chevy 6.6 gas engine good?

Yes, the Chevy 6.6 gas engine is good. This engine is more than sufficient for most uses. With a towing weight of up to 17,370 lbs, maximum weekend warriors can take their yachts to the river or tow their toy haulers with sand carts in the back out to the sandbanks. This gas engine is also cheaper than diesel engines as you require to pay nearly $10k more for a diesel engine.

How is the new Chevy 6.6 gas engine?

The new Chevy 6.6 gas engine is rated at 401 horsepower and 464 lb-ft of torque, an 11% rise in horsepower and a 22% rise in peak torque compared to the previous 6.0L gas engine. This engine also has up to 18% more towing capacity than the last engine gas.

Is the 6.6 gas an LS engine?

No, the 6.6 gas is not an LS engine. It is an LT engine. The 6.6 gas engine debuted in the 2020 Chevrolet Silverado HD and 2020 GMC Sierra HD. This engine is built on a cast-iron block LT engine, capable of producing 2,000 HP in a forced induction application.


The Chevy 6.6 is a great motor for the price, but it does have some problems that owners have to deal with from time to time. Many people love this engine even after migrating from Ford or Dodge, while others have a contrasting perspective because of the new chevy 6.6 gas problems.

While most of these problems are minor inconveniences and easy fixes, some could cause major damage if they’re not addressed immediately. We have elaborately discussed all the chevy 6.6L engine gas problems and their reasons that can help you to solve these problems.

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Ronald Berit

Our chief editor, working 24/7 to ensure the precise and only quality data regarding different trucks.He is mastered with the ins and outs of cargo to off-road trucks of Dodge, Ford, Chevy, Toyota, GMC and more. This truck geek graduatedwitha Bachelor of automobile engineeringdegree and practiced through his own automotive parts repair center.

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