Are Hummers Reliable? 16 Most-Common Problems (Examples)

You’ve probably heard enough bashing of the Hummer. It is a gas guzzler, sluggish, maintenance freak and all sorts.

Are these claims true? Will you be making a huge financial mistake if you get a Hummer? Let’s find out in this piece.

Are hummers reliable?
Hummers are among the most reliable vehicles ever made. That being said, they do have issues. The early models are getting old and they each had their problems.

Let’s dig into the details!

Why Early Hummers Had Issues

The first Hummers were military vehicles adapted for civilian use. You won’t find their parts lying around your street corner auto repair shop.

And the average mechanic doesn’t have a clue about any of the Hummer’s headaches. You need professionals with special skills to handle their complicated systems.

The best places to appreciate the strength of the Hummer are enthusiasts’ forums where people share the problems and challenges they face with their beloved workhorses.

Even the H2 and the smaller H3 Hummers are not your typical SUV because they have bigger and more powerful engines.

These trucks will go anywhere you want them to go including high altitudes, streams, deserts, and everything in between.

Later models have improved fuel efficiency despite their gas-guzzling reputation. In fact, the Hummer H3 could do 13 mpg city, 18 mpg highway, which is far better than the H1’s 8-10 mpg combined.

A lot of the misconception about the Hummer stems from the bad press from eco-activists. In reality, the vehicle has far better performance characteristics on and off-road compared to trucks in its class.

However, the Hummer is maintenance intensive. Different model years have distinct issues that will require regular attention.

A Hummer is difficult to maintain except you are doing the work yourself.

But not everybody has the skill-sets except maybe for veterans who served with the truck or highly skilled civilians.

Below, we look at the common problems that can reduce the reliability of your Hummer.

Look into our article which reads about Hummers & Depreciation: Here’s What To Expect

5 Typical Problems With The Hummer H1

The 2006 Alpha H1 is the most reliable H1 Hummer. Everything about the vehicle is excellent including the heavy-duty Duramax 6.6-liter Turbodiesel, exceptional AC-Heating, improved traction, reinforced suspension, more fuel capacity, and impeccable creature comforts.

However, earlier versions were not as lucky.

So long as you take good care of the truck, it will serve your reliably even with over 100k on the odometer.

Here are some issues with the H1.

1) Wear and Tear

The first H1s, i.e., the 92-93 models suffered serious wear and tear because of their poor heat insulation.

The heat created a lot of problems for the cylinders and made the interior uncomfortable since it lacked air conditioning.

However, they were easy to maintain because they had no digital controls.

2) HVAC Issues

In the 1994 model, the new HVAC system installed to correct the heating issue of earlier models was not up to the job.

The heater core was susceptible to failure but AM General replaced faulty systems. Another issue with the 94 model was that its NA diesel engine was underpowered.

This made the Hummer to struggle at high altitudes as the engine runs out of power even while on the road.

Faulty heater cores used in the 94 Hummer can cost up to $3,000 to replace, so you want to make sure you are not paying for replacements.

3) Traction Issues

If you are buying a 99 H1 model, check the traction system. While the model had new heating and cooling systems and exceptional performance, it used an electronic traction system called TT4.

The TT4 wasn’t a match for the trusty Torsen II in earlier editions and lacked the legendary traction of its predecessor.

This made it ideal for on-road use but not the best on the trails.

4) Parts Availability

The 2006 Alpha is superior to all other H1s. But it is also more expensive and parts are difficult to find.

So while you may not have many issues with the vehicle, getting it to serve you in excellent condition for a long time might be expensive.

5) Cracked Engine Block

If you plan to buy H1s from the 96-2000 stock, you might have heard they are susceptible to a cracked engine block.

During manufacturing, there was a flaw in the number eight cylinder casting of the turbo diesels at GM’s plant.

Fortunately, AM General replaced faulty engines under warranty. But not all the affected vehicles may encounter the problem during the warranty period.

You want to check that the model you are buying does not have this problem. And if it is, go for one that has got a replacement engine.

6 Common Problems With The Hummer H2

The Hummer H2s don’t seem to have any major issues. Most people are happy with them.

With regular care, these beauties are reliable and will always get you to the destination.

However, here are a few things to look out for:

1) Windshield Wiper Circuit Board Short

A common problem with the H2 is the shorting of the windshield wiper circuit board. This happens when moisture gets into the board and can cause the windshield wiper to come on when it’s raining.

A replacement will solve the problem but you can get it fixed at no cost because it is a factory defect.

2) Door Lock Switch Short

Again, this is a common issue and you can easily replace it.

3) Off-roading Issues

If you use your H2 for a lot of off-roading, it will experience a lot of issues far more than road queens.

The hubs will receive some serious bashing and require regular care. You also have to deal with tie rods going bad, creaking ball joints, and failing Idler & Pitman arms.

The transmission cooler will heat more often.

In fact, you may have to check your H2 every time you come back to the civilized world if you are a heavy off-roader.

4) Mirror Not Folding

Many H2 owners complain about the mirror not folding.

This is common to the 2003-2005 model years but GM fixed them under warranty.

Again, this is not a big problem but can be annoying when you need to park in a public space.

5) Failed Speedometer and Tachometer

Another common issue with H2s is the speedometer and tachometer failing without warning. While this does not affect the performance of the vehicle, it’s impossible to tell your speed.

6) Oil Pump Failure

Some users complain about their oil pump losing pressure suddenly. If the warranty does not cover you, this problem can cost you $1,500.

5 Common Problems With The Hummer H3

Of all the Hummers produced, the Hummer H3 is one of the most beloved and the most hated.

In fact, the 2006 H3 was so problematic for many owners, and most of the problems were from factory defects.

Here are some major issues with the H3:

1) Engine Runs Rough

The biggest issue with this vehicle seems to be its rough running engine.

When the vehicle gets past the 50k mile, you notice that the engine runs rough, even while idling.

And the worst part is the dealership may not find the solution at once.

Some people resolved the issue by replacing the head gaskets. Others had to replace the cylinder heads and leaking engine valves.

For some users, the problem kept cropping up even after changing the spark plugs, valves, head gaskets, and the radiator.

Check out our article that talks about Are Hummers 4×4?

Be careful when buying Hummer H3s, especially the problematic 2006 edition.

If it’s past 50k or out of warranty, there seems to be a legion of problems that afflict the H3. Sadly, a fix can cost upwards of $3,000.

2) Blown Head Gasket

Many H3 owners, particularly the model year 2006 discovered that the Head Gasket blows off when the vehicle crosses the 100k mile.

GM knew of the weakened head gasket but didn’t recall the affected vehicles.

The result was that many users encountered blown head gaskets after the vehicle was past the warranty period.

This meant they had to fork out over $2,000 for a replacement.

3) Check Engine Light

Owners have also complained of the Check Engine Light coming on by itself and refusing to go off.

When this happens, the engine runs rough and no amount of diagnostics will work.

 It seems the solution to the problem is to change the cylinder heads and valves, a repair that will set you back by almost $3,000.

The worst part is that GM knew of this problem all along.

Rather than recall the problematic vehicles, it treated them on a case-by-case basis.

Some owners were out of warranty when the problem occurred and had to foot the bill.

4) Cylinder Head Failure

Another big issue with the Hummer H3 was its weakened cylinder heads and valve seats. Again, GM knew of this problem but didn’t alert users.

It was only when people started experiencing the same issue en mass they discovered it was a manufacturing defect.

Even if you have low mileage, the engine can misfire and fry the cylinder heads.

If you are out of warranty, get ready to spend about $2,900 for the replacement.

Many people are not happy with the faulty heads, but there’s nothing they can do.

5) Leaking Valves

Users of the Hummer H3 also complain a lot about faulty and leaking valves.

You can experience the problem as early as 40,000 miles which should be under warranty.

As many owners have discovered, leaky valves are a continuous problem with some models of the H3. You will eventually need to pay for future valve or cylinder head replacements.

General Issues

If you use your Hummer on the pavement, you won’t have any problems except your model has factory defects.

For off-roading, you may have to change the tires and the oil more frequently.

The brakes and suspension will also take a heavy beating.

Final Words

Regardless of the model or year of Hummer you own or plan to buy, the vehicle is maintenance intensive.

The Hummer has exceptional capabilities but also requires constant care. Before buying one, it’s advisable to see the maintenance records to ensure that the vehicle is in good shape.

You will get excellent service and reliability from a Hummer if you don’t slack on maintenance. But don’t forget it’s an expensive vehicle to own.

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