In this piece, we look at the different models of the Hummer and the engines they use. At the end of this piece, you will have all the information regarding the fuel needs of every Hummer model.
Table of Contents
Do Hummers Run on Diesel?
All Hummer H1 models except for some 1995 and 1996 models are powered by diesel engines. H2 and H3 models typically run on regular 87 92 octane gas.
Hummer H1s produced before 1996 used naturally aspirated diesel engines while later versions came with the more powerful turbo-diesel which increased torque at low speeds and mileage.
The production of Hummers is discontinued but their gas-guzzling reputation never goes away. Diesel engines are more efficient than gas-powered types. Enthusiastic Hummer lovers still ask whether the truck uses diesel.
List Of Hummers And Fuel-Types
|Model, Year||Type of Engine|
|Hummer H1, 1992-1993||Diesel|
|Hummer H1, 1994||Naturally Aspirated (NA) Diesel|
|Hummer H1, 1995||NA Diesel, Gas|
|Hummer H1, 1996||NA Diesel, Turbo Diesel, Gas|
|Hummer H1, 1997||NA Diesel, Turbo Diesel|
|Hummer H1, 1998||NA Diesel, Turbo Diesel|
|Hummer H1, 1999||Turbo Diesel|
|Hummer H1, 2000-2003||Turbo Diesel|
|Hummer H1, 2004||Optimized Turbo Diesel|
|Hummer H1, 2006||Duramax Turbo Diesel|
|Hummer H2 & H3||Gas|
The Hummer, starting from the H1 to the H2 and H3 models were civilian variants of the military HUMVEE.
AM General created the Humvee for the US Armed Forces. The vehicle’s success during Operation Desert Storm endeared it to the public.
Because of the demand for a civilian version of the venerable Humvee, AM General created the Hummer H1 in 1992.
One of the greatest advocates of a civilian Humvee was the former Governor of California Arnold Schwarzenegger. He was the first person to own the Hummer.
Production ran from 1992 when the H1 debuted to 2010.
In 1999, General Motors bought the rights to produce the popular vehicles under the Hummer brand. However, AM general continued to produce the GM-designed H2 while the H3 was produced at GM facilities.
First, let’s take a look at the Hummer H1.
The Hummer H1 And Fuel Types
The H1 models of 92 and 93 were powered with a 6.2-liter diesel engine with a 3-speed transmission.
These vehicles came with a 25-gallon fuel tank, small for a truck that gives only about 5 miles per gallon.
A lot of users complained about the diesel in these Hummers as underpowered, and the 3-speed transmission makes them poor for on-road use.
However, they are excellent for off-road use, and less complicated to maintain because of their manual controls.
The 1994 iteration of the Hummer received an upgraded diesel engine and transmission.
These vehicles featured a naturally aspirated 6.5 diesel engine paired with a 4-speed transmission from GM.
The 4-speed transmission delivered increased torque at low rpm, improving fuel efficiency and reducing noise and engine wear.
However, these engines struggle at high altitudes and still lack the bite of more powerful turbo diesels found in trucks their size.
In 1995, AM General introduced a gas-powered model alongside its diesel Hummers because of customer demand.
The 350 Chevy V8 gas-powered engine shared the diesel’s poor road performance.
It guzzled fuel at 7-11 mpg and the tank held only 23 gallons to create room for the fuel pump and vapor.
This made the gas variant of the 95 Hummers short-legged. And it didn’t have any noticeable advantages over its diesel cousin on and off the road.
The only plus in the 1995 and later models was the improved interior and exterior design.
After receiving customer feedback on the short mileage of the 95 gas-powered Hummers, AM General included an extras fuel tank on all the 96 vehicles.
The two fuel tanks could take 42 gallons, increasing mileage.
The 1996 models ushered in the turbo diesel, boosting the performance of this type in off-road and road conditions.
Meanwhile, AMG was still producing naturally aspirated diesel-powered trucks alongside the turbo.
Sadly, the company stopped the production of gas-powered engines in 1996.
A design flaw in the GM turbo diesel used in the 1996-2000 Hummer models increased the risk of the engine block cracking.
In 1997, AM General had fine-tuned the turbo diesel engine. The engine delivered more power, made less noise thanks to improved sound insulation and was cooler.
Vehicles produced in the second half of 97 also received numerous upgrades to the cooling and heating system for improved performance.
1998 Hummer models used diesel engines including the turbo and naturally aspirated types. The 98 model was quieter thanks to improved sound insulation.
It boasted more balanced axle ratio and overall improvement in the vehicle design.
In 1999, the turbo diesel became the only engine type used in Hummers as AM General stopped using the naturally aspirated diesel.
It also saw the introduction of the electronic traction system (TT4), improved sound insulation, and exceptional on-road capabilities.
However, customer feedback showed that the electronic controls were underwhelming compared to the older Torsen 1 differential that gave the Hummer its spectacular traction.
AM General corrected flaws in the traction and other issues in later models.
The Hummer trucks produced in 2000 through 2002 shared most of the characteristics of the 1999 model.
These trucks featured turbo diesel engines, improved traction, exceptional on-road performance, and more creature comforts.
During this period, General Motors acquired the Hummer brand.
The 2003 Hummer H1 was also a turbo-diesel but with improved off-road characteristics.
This was achieved through the installation of an Eaton electrical rear locker for best-in-class traction.
The turbo diesel has now matured and delivers an exceptional range and torque even in the most daunting terrain.
In 2004, the Hummer shipped with the Optimizer turbo diesel which bumped output by 10 horsepower.
The 2004 model also introduced the computer engine controls in line with new EPA smog standards.
Thanks to enhanced sound insulation, this model was exceptionally quiet, which enhanced driving comfort.
GM did not produce a Hummer H1 model in 2005.
2006 Alpha H1
The 2006 Hummer is called the Alpha. It comes with a bigger and more powerful Duramax Diesel engine and an Allison transmission, necessitation a redesigned drive train and new steering system.
The tanks had to be redesigned to meet DOT requirements, increasing the fuel capacity to 51 gallons. While the Alpha is bigger and more powerful, it’s also more expensive and difficult to maintain.
This is because it was the last Hummer H1 model to be produced and the only one of its kind.
You may only service the vehicle at the factory because spares are hard to get.
H2s and H3 Hummers And Gas Types
All Hummer H2s and H3 came with gas engines.
There were different engines for specific model years. But the bigger H2s sported larger and more capable motors.
Should You Buy a Gas or Diesel-Powered Hummer?
There is a big difference between a gas-powered engine and a diesel engine.
And there is an even greater difference in the performance of a naturally aspirated diesel and a turbocharged diesel engine. Let’s look at the pros and cons of the different Hummer variants.
Plenty of gas-powered Hummers featured the Chevy 350 small block engine. This engine is the most ubiquitous engine ever built and has the largest number of add ones of any automotive system.
Gas engines are easier to maintain even if you suffered a serious blowout in the most obscure part of the country.
And they are also cheaper, so you can find a replacement at a rock bottom price in case of a catastrophic failure.
Gas engines start easily even in the harshest winter month.
They run quieter and can be better insulated compared to the diesel engine.
Gas engines work seamlessly at altitudes thanks to their exceptional fuel injection system so you won’t have to contend with huge plumes of smoke.
The gas truck delivers more compression engine braking, allowing it better control during steep descents.
The gas-powered Hummers run out of power when climbing steep hills. They also underperform when towing trucks at high altitude.
Plus, these Hummers have a limited water fording capability because their high voltage ignition system is not sealed.
The gas engine transfers more heat into the cabin. It requires more power when going over obstacles because the engine achieves peak torque at higher rpm compared to diesel.
Diesel Powered Hummers
The NA diesel-powered Hummers H1s have similar performance characteristics with the gas models. They can’t achieve high speeds on the road and off-road.
NA diesels were also harder to start in cold weather because the fuel can become gel-like. Plus, they give off a lot of smoke in high altitudes.
The Turbodiesel Hummers are the all-around winners in terms of performance.
These models crank out more torque at low rpm. They also have enhanced mileage and fuel efficiency.
These trucks have no problem at high altitudes, can hit over 90 mph and above on the highways and deliver exceptional performance in off-road situations.
The turbo-diesel also have improved cooling which increases torque, higher transmission for longer range and much better heat and sound insulation.
The early Hummer H1 is a predominantly diesel affair but the H2 and H3 delivered better road performance.
If you want better mileage, powerful performance and improved control on and off the road, the clear winner is the turbo diesel models.
But you will have to forgo the luxury of the H2 and H3 to drive a turbo-diesel Hummer.
So if you are considering buying a Hummer, we hope this article will help you make the right decision.