How Do You Diagnose A Diesel Engine Problem?

  • Examine the rad’s air flow. In the summer, make sure it isn’t obstructed by bugs, and in the winter, make sure it isn’t stopped by snow and ice.
  • Make sure that all of the axles are moving freely. Make sure there are no dragging brakes or tires.
  • Check the temperature of the air outside. If it’s terribly hot outside and you’re driving, lower the gears.
  • In hot weather, turn off the air conditioning on steep climbs. This will aid in the cooling of the engine.
  • Examine the batteries and the connections to the starter. It’s possible that there’s a shaky connection.
  • Check for contaminants in the gasoline. Fuel filters should be changed. Fuel that is dirty will cause issues.
  • Air filters should be checked and cleaned. If required, replace the item. Filters that are clogged will also starve the motor.

Excessive smoke from the engine is almost always a sign of impending engine trouble. The different smoke colors can assist you in pinpointing the source of the problem.

  • White smoke can indicate a problem with the engine’s timing or compression.
  • Dirty air filters, poor injectors, a turbo problem, or a cylinder head problem can all cause black smoke (insufficient fuel to the cylinder).

What are common problems with diesel engines?

One of the advantages of having a diesel engine pickup, such as a Ford Powerstroke or a Dodge Cummings, is that it requires less maintenance than a gas-powered pickup. However, this does not negate the necessity for routine maintenance and upkeep. Repairs will be required if diesel engines are not serviced on a regular basis.

These are eight of the most common diesel problems:

1. A challenging start. As a diesel owner, you’re aware that when they’re started, they sometimes crank a little. However, if starting your truck becomes extremely difficult – or if it refuses to start at all – you should have it serviced.

2. A lack of authority. A common fuel-related issue in a diesel truck is a lack of power. Dirty fuelfilters, excessive lubrication, fuel injector issues, and a faulty throttlelinkage can all contribute to difficulties starting and accelerating a diesel truck.

3. Fuel that has been tainted. Because diesel fuel is heavier than gasoline, it is more easily polluted. Glycol, soot, and water are the most prevalent pollutants. Any of these impurities could cause major engine difficulties if they get into the fuel system.

4. A lead/acid storage battery that is faulty. A diesel pickup’s starter system relies heavily on the lead/acid storage battery.

5. Exhaust that is black. When the air/fuel ratio is out of equilibrium, black exhaust might result. This usually indicates that there is too much gasoline and not enough air. This problem can be caused by a clogged air filter, a broken injector or injector pump, a malfunctioning turbocharger, or a broken EGR valve.

6. Oxidation of the oil. When a diesel truck sits for too long and isn’t operated on a regular basis, oil oxidation can occur. Oil oxidation happens when air enters the oil and forms bubbles, preventing proper lubrication and potentially causing engine damage. You should change the oil in your diesel truck if it has been sitting for a long time.

7. Weight viscosity is incorrect. Hard starting is frequently caused by an inappropriate weight viscosity of engine lubricant. Diesel lubricants have a far higher viscosity than gasoline, and many people will use the incorrect weight when maintaining their diesel on their own.

8. There is an excessive amount of noise. The sound of a diesel engine is louder than that of a gasoline engine. That is simply a fact. There are times, though, when the noise becomes excessive, signifying a concern. If you hear a strange knocking or other strange noise, it could be a sign of a problem with the fuel injectors. This could wreak havoc on your compression balance, as well as your overall performance.

Call on the professionals at Gem State Diesel to keep your diesel engine in top shape. We specialize in the repair and service of light, medium, and heavy-duty diesel trucks, and have a reputation in the Boise area for providing excellent diesel pickup repair and service. Call 208.957.6106 or use the form below to make an appointment.

What causes diesel engine malfunction?

The most prevalent problem that causes diesel engines to fail is a combination of water and diesel fuel. Water can enter your fuel system in a variety of ways, including:

  • Using diesel fuel that has been contaminated by water at the pump. Inefficiencies in the transportation or storage of the fuel can cause this.

Contamination with water can cause major engine damage and inefficient performance. When your diesel is mixed with water, it is unable to provide the maximum power. Rust can form in your fuel system if water is present for an extended period of time. It can also lead to microbial development and blockage of fuel injectors and filters.

Rust dislodges microscopic metal particles as it eats away at the interior elements of your fuel system. As the fuel runs through your engine, these particles become suspended in it. Rust particles have abrasive properties that might harm your engine’s most delicate components. They can also degrade the integrity of your seals, valves, and filters, compromising their performance.

How do you know if your diesel engine is blown?

Blue smoke isn’t a nice thing. Here is a link to a complete article detailing all of the potential issues. Your engine is burning oil in some way if you see blue smoke. This is not always due to worn components, but it is a common occurrence in older engines.

If you’ve determined that the issue isn’t with the gasoline system, it’s likely that an engine component is malfunctioning. As the engine ages, you’ll notice more and more blue smoke. Over time, the clearances on the cylinder walls simply cannot be maintained, and oil accumulates on the walls of the cylinder. When the piston returns to its original position, oil is left in the chamber, where it is burned together with the fuel.

Once again, a compression check will reveal the source of the problem. It’s possible that a complete in-frame rebuild is required if it’s quite old. That oil has been traveling through those rings for a long time, as you can see below.

What diesel engine has the least problems?

The 7.3L Powerstroke is still widely regarded as one of the most dependable diesel engines ever produced. With 500 pound-feet of torque and 235 horsepower, it offers enough power for most purposes. With an air-to-air intercooler, oil-based fuelling, and long-lasting internal hard parts, it was built to last. When properly maintained, the Super Duty from 1999 to 2003 may travel much beyond 500,000 miles. If you’re looking for a secondhand 7.3L Powerstroke, you can get a fair deal on one with 150,000 to 250,000 kilometers.

What is the most common cause of engine failure?

Low amounts of engine oil are most likely the most common cause of engine failure. Even if you replace the oil regularly, you should check the oil levels on a regular basis to ensure there isn’t a leak or that your car isn’t burning too much oil. Engine oil starvation can be caused by a defective oil pump, excessive mileage wear and tear, or gunky oil by not changing the oil and/or filter at the required intervals. Maintain your car’s engine on a regular basis to keep it in good working order.

How do you know if your diesel needs to be rebuilt?

There are a variety of reasons why you might need to rebuild your diesel engine. The following are some signs that you might have a problem that needs to be looked at.

Power Loss

Loss of power may suggest a problem with your camshaft, but it could also indicate a more serious problem with your engine. Fuel issues, particularly severe fuel contamination, excess buildup, injector issues, a defective turbo, or air entering the system can all cause this.

Poor Fuel Economy

If your camshaft is having problems, such as lobe wear, you may notice a drop in mileage. There’s a risk that bad driving behaviors, such as carrying too much weight or accelerating quickly, are causing a decline in fuel economy. It could also indicate that your diesel engine needs to be rebuilt. It’s possible that your gasoline is polluted, that you have a problem with your filter or injectors, or that you have a leak in your system.

Check out our 5 Simple Methods to Improve Fuel Economy if you’re seeking for ways to save money at the pump.

Excessive Oil Consumption

If your engine is using more oil than usual, you should identify the problem before it leads to a serious system breakdown. Dirty oil, too much oil in the crankcase, excessive engine vacuum, too little end clearance of piston rings, worn or damaged piston rings, oil pressure too high, lugging engine, or restricted air intake could all be contributing factors.

The piston rings become compressed in the ring groove as a result of carbon packing caused by malfunctioning EGR systems, and are no longer able to hold combustion gasses on the top side or manage the oil on the bottom side. If oil is burning or leaking, it can cause other problems and result in a more expensive repair if not addressed immediately.

We offer further information regarding high oil consumption if your rig is guzzling oil.


Engine banging can signify a major problem with your engine, therefore it’s important not to dismiss it. Compression issues, malfunctioning fuel injectors, timing issues, failing bearings, and a failed wrist pin bushing or wrist pin are all possible reasons of engine banging.

Compression Issues

A lack of compression is one of the most obvious signs that your engine has a problem that has to be addressed. Leaking/broken valves, leaking/broken piston rings, blown head gasket, camshaft troubles, broken timing belt, or a hole in the piston or cylinder are all signs of compression problems.


Excessive smoke coming from your exhaust, especially blue or black smoke, can indicate a major problem with your engine. This could suggest a variety of issues, including malfunctioning injectors, injector pumps, air filters, EGR, turbos, carbon build-up, inefficient or incomplete combustion, worn valve guides or seals, or wear in power assembly.

How do I know if my piston rings are bad diesel?

The piston rings in your car’s engine are in charge of regulating engine oil consumption and controlling oil pressure. Engine rings that are worn or cracked can cause a slew of issues, necessitating engine repair. Here are some of the warning indicators that your vehicle’s piston rings are fried.

Common Symptoms of Damaged Piston Rings

The symptoms and signals of problems with your car engine’s piston rings are often the same as those of other vehicle problems with low compression. While the following symptoms aren’t necessarily linked to damaged piston rings, they are a solid indication that you should inspect them for wear and replace them if necessary. The following is a list of the most prevalent signs and symptoms of faulty piston rings:

If you suspect your vehicle has faulty piston rings or is exhibiting any of the symptoms listed above, you should have a compression test performed on the engine. A compression test entails removing one of your engine’s spark plugs and attempting to start it with a compression gauge attached to the cylinder where the plug was removed. You can buy a compression gauge and perform the test yourself, or you can have the vehicle diagnosed by a trained mechanic.

What is the most unreliable diesel engine?

The 6.0L Powerstroke is a well-known engine. Because of the engine’s poor performance, Ford and Powerstroke’s parent company, Navistar, were involved in a lengthy court dispute. Ford said Navistar produced a faulty engine. Ford has ignored unsatisfactory test results for the 6.0L Powerstroke, which could have prevented post-production issues, according to evidence.

As the Powerstroke suffered catastrophic failures, expensive engine replacement warranty claims flooded in. The cab of the vehicle had to be removed for the majority of these repairs. Because to this engine, many owners have lost faith in the brand. A series of recalls affecting this notoriously problematic truck are listed by Consumer Reports.

Which diesel engine lasts longest?

Because diesel pickup trucks have more durable engines that can sustain greater compression ratios, they often obtain better economy than gas trucks. Powerstroke, Cummins, and Duramax diesel vehicles often last well beyond 100,000 miles, even when used frequently for towing and hauling. As a result, diesel pickups with 200,000 or even 300,000 kilometers sometimes attract high resale values on the secondhand truck market. Drivers shopping for a used diesel pickup understand that a truck’s life isn’t over just because it has a lot of miles on it.

With modern trucks surviving longer than ever before, it’s not uncommon to come across gas trucks with 200,000-mile lifespans. Diesel trucks, on the other hand, can exceed that limit. Diesel pickup trucks may easily last 500,000 miles or more. It isn’t simply their engines that are more durable. Because diesel engines are heavier than gas engines, diesel vehicle hulls are designed and constructed to be more durable.

Not all high-mileage diesel trucks are created equal, much like other cars. For example, a diesel truck that has been used extensively for towing and transporting large loads for 100,000 miles may require serious repairs, whereas a diesel pickup that has been rarely used and has 200,000 miles on the clock may still have years of trouble-free life ahead of it. However, it’s also crucial to know that the life expectancy of a diesel vehicle is determined by a variety of other elements outside the odometer reading, such as:

For example, a 200,000-mile diesel pickup with only one or two owners and strong maintenance records is likely to be a better investment than a 100,000-mile vehicle with four owners and few records.

The general condition and appearance of the truck are also significant. A truck with a well-kept exterior and interior is likely to have had its mechanical components well-kept as well.

Duramax is a brand of diesel engine found in GMC and Chevy vehicles manufactured by General Motors. What constitutes excessive mileage for these engines is a matter of debate. Some owners consider 100,000 miles to be excessive mileage for Chevy diesel trucks, while others believe that anything less than 350,000 should be considered high mileage. A poorly maintained engine might swiftly deteriorate before reaching 100,000 miles, whereas a well-kept Duramax pickup truck should last 400,000 to 500,000 miles.

Cummins engines can be found in Dodge diesel trucks and Ram diesel trucks. Cummins diesel engines, like the Duramax, are designed to last a long time. On a Cummins diesel, 350,000 to 500,000 kilometers is normally considered high mileage. Of course, this is dependent on how well the engine is maintained.

Although maintaining the engine is crucial, some diesel pickup drivers believe it is even more important to keep the truck alive around the engine because the truck itself is less likely to last more than 500,000 miles, even if the diesel engine is well-maintained.

The Powerstroke engine, like the Duramax and Cummins engines, is found in Ford trucks and can last up to 500,000 kilometers. However, similar with the Duramax and Cummins engines, a Powerstroke engine with 350,000 to 500,000 miles on the clock is considered high mileage. The key to gaining the most miles is to keep the truck and engine in good shape. Ford vehicles are the most popular truck brand in the United States, and they’re regarded for their overall dependability.

Purchasing a diesel pickup truck with at least 250,000 kilometers could be a good deal. Diesel pickups are more expensive than their gasoline counterparts when new, so buying one used might save you a lot of money. When purchasing a used diesel truck, keep the following in mind:

Oil leaks are common in high-mileage engines, but they aren’t always cause for concern. It’s not uncommon to have small leaks around gaskets and seals. A little oil seepage around the front and rear main seals, for example, isn’t all that concerning and is even expected. Oil that is more densely coated around a seal or gasket, on the other hand, may raise suspicion. It depends on how much oil is smeared across the surface. To put it another way, while having no oil leak is definitely better, a tiny oil leak on a high-mileage diesel engine shouldn’t necessarily be a deal breaker.

When purchasing an older diesel truck with a mechanical injection system, it’s a good idea to start a diesel fuel additive routine. Long-term running without supplemental lubrication of one of these older diesel engines can result in early injection pump failure. A fuel additive, on the other hand, can improve modern diesel engines. Additives can help any diesel engine, whether it’s a high-mileage or not, get better gas mileage.

Distinct trucks and engines, like any other vehicle, have different challenges. Buying an engine model that appears to have the fewest difficulties may be irrelevant if the truck it’s in has issues. It’s also crucial to look into the individual truck’s troubles, in addition to the engine’s concerns. Maintenance records can be extremely useful in this situation.

For example, the water pump on a particular truck may fail every 100,000 miles or so. Even if a truck has 300,000 miles on it, if the water pump hasn’t been updated in 150,000 miles, you could be looking at expensive repairs.

On a high-mileage diesel truck, it’s never too late to switch to synthetic engine and gear oil. The following are some of the advantages of synthetic oil:

Heat, repetitive mechanical pressures, and chemical breakdown from fuel dilution are the major enemies of oil stability. All of these forces are more prone to higher-mileage engines. Synthetic oil can help a high-mileage diesel engine last longer and run more efficiently.

Synthetic oils, in the end, minimize friction better than traditional lubricants. Friction can increase as diesel parts wear out in high-mileage engines. More friction equals more heat, which accelerates the deterioration of oil and diesel truck parts.

To summarize, there is no single number that defines what constitutes high mileage for a diesel pickup truck; however, anything beyond 500,000 is commonly considered excessive mileage. However, remember that there are many more factors to consider when purchasing a used diesel pickup than mileage. A well-maintained, high-mileage Powerstroke, Cummins, or Duramax diesel pickup truck is almost always a better option than a poorly-maintained, heavily-used diesel pickup truck with lower mileage.