The more miles that an engine has covered, the lower will be its reliability. But diesel trucks and cars usually hold better value than their gasoline-powered counterparts, even after covering a few thousand more miles.
Why does that happen, and is it worth paying the premium? This article will answer all related questions.
Should You Buy a Diesel with 200k Miles?
The answer to this question should depend on several factors that play a huge role in determining the reliability of the engine. Not every mileage is equal, different drivers drive their vehicles in different ways. This difference is also apparent when it comes to maintenance and repairs too.
You should be able to assess the condition of the vehicle based on how it looks, drives, sounds and by taking a look at the maintenance records. Based on your judgment, you should decide on the best deal you can find. If you do not trust your judgment, you can always hire a mechanic to do that for you. Sure, it will cost a bit more, but it will not be as expensive as repairing a defective car.
Before you make a decision, you should account for all of your previous observations. Many faults can be easily repaired. You can use that to bring down the asking price of the vehicle. But then there are a few defects that are not worth the cost and effort of repairing. If you find anything of such seriousness, just remind yourself that there are a plethora of other options available and move on.
If all of the conditions align favorably, you should absolutely go for it. It might prove to be one of your best investments as some of the well-maintained examples have the potential to outlive you.
Also read: Do Diesel Cars Need to Be Driven Regularly? [Solved]
Is 200k Miles Too Much for a Diesel?
For big diesel engines used in trucks and SUVs, 200k miles is not a ridiculously high mileage. With proper maintenance, you should be able to drive it for another 200k miles without breaking a sweat.
Diesel engines are often used in big and heavy trucks. And many drivers will not even consider a 200k miles engine as a particularly high mileage example. Anything below 350k miles will not be considered high mileage for such big and powerful engines.
The bigger engines also have robust construction, which allows the use of heavier and bulkier parts for their construction. Enabling it to endure a lot of stress from carrying heavy loads without negatively affecting the components inside the engine.
Also, a diesel engine will last longer than a gasoline engine with the same amount of mileage due to several reasons. Diesel engines have higher compression ratios and higher cylinder pressures, which necessitates the use of bulkier bolts, crankshafts, and crankshafts.
The diesel fuel has some degree of lubrication properties, so the fuel itself acts as a lubricant inside the engine. It lowers the internal stresses between metal components and helps to regulate the temperature of the entire system.
The diesel engines produce a lot of torque low down in the rev range, which means that it operates at a relatively lower RPM during the majority part of their operation. This also contributes significantly to the longevity of the engine.
This might come as a surprise to you if you are new to the world of big diesel trucks. But it makes a lot of sense when you realize that many of the well-maintained cars can last up to 400k and even 500k miles without requiring any major repairs.
The smaller engines might not last that long due to several reasons. Firstly, due to their smaller size, they do not produce as much power, so they are forced to work harder for better performance. And they use smaller components to abide by the weight restrictions.
What are the Risks of Buying a Diesel with 200k?
The main risk of buying a high mileage diesel is the maintenance and repair costs that entail it. Diesel vehicles are notorious for their high maintenance costs. And this is one of the primary reasons that drive away newer owners from buying a diesel-powered car.
The mileage on the odometer may not always paint a clear picture of how much the truck has been used. If the truck has spent most of its time idling away in city traffic, the engine wear might be in reality similar to a 400k mile engine, even though the odometer only shows 200k miles. The same applies if the truck has been used to constantly tow heavy objects.
So if you are buying a diesel-powered vehicle, and you do not have a clear idea of how the vehicle has been used by the previous customers, you risk being sold a worn-out engine even though it has not racked many miles. It will end up costing you a few thousand dollars to do all the necessary repairs to keep it running.
They cause more pollution than gasoline cars, and in this day and age when we are aware of the harmful effects that it can have on our earth, diesel vehicles may not be around for a lot more years. Another risk is the potential regulations that might be enforced by the government in the coming years. The operational period of diesel engines has already been capped in several countries. And many more countries have scrappage policies for diesel vehicles in the pipeline.
Also read: Do Car Salesmen Get Discounts? (Explained)
What are the Advantages of a Diesel with 200k? (if You Choose the Right One)
Diesel powertrains are highly fuel-efficient. Instead of spark plugs having to ignite the fuel, diesel engines rely on the heat from the compression to burn the fuel. Since the compression ratio is higher, the fuel burns slower and more completely. The fuel efficiency will be approximately 30% better than the gasoline engine of comparable size.
Diesel engines are built to withstand adverse conditions. People rely on diesel-powered trucks to transport goods in the bone-chilling winters of the arctic and also in the barren deserts of Africa. Manufacturers understand these requirements and build the cars with utmost craftsmanship and heavy, durable components that can survive such conditions.
Diesel engines produce a lot of energy, which means that they will be able to provide a lot of torque even from the very lower end of the rev range. This makes diesel-powered vehicles perfect for towing applications. They can also carry heavy objects up steep inclines with relative ease. Gasoline engines that have to be revved out to produce more power will struggle in such conditions.
The versatility of diesel-powered vehicles is virtually unmatched. Most new diesel engines are refined enough that you will not be able to differentiate them from a gasoline engine. But offroad, where gasoline engines struggle, diesel engines will glide through. As a result, diesel vehicles tend to hold their value much better than their gasoline counterparts.
Also read: Do Hybrids Last Longer than Gas and Diesel Cars?
What to Look for When Buying a Diesel with 200k?
Even before taking the car for a test drive, do your research. Search for the common problems that plague that vehicle, if any. Try to find out what parts are likely to fail after it covers a certain amount of mileage.
And check whether that part has been replaced in the vehicle that you would like to check out. If it has been replaced, that is one less thing to worry about. If it has not been replaced yet, you can use it to bring down the price by quite a margin.
During the test drive keep your ears out for any abnormal sound emanating from the engine or transmission. Run it through all the gears, lock the differentials and also engage the four-wheel drive to make sure that all of it works.
If you have made sure that the engine and transmission run smoothly without any vibrations out of ordinary, go to the rear of the vehicle and check the emissions. If the car emits black smoke or other particulates during a cold start or when it is revved up, it is a potential engine repair. And you may not be able to pass the necessary tests without doing it. Get under the vehicle with a flashlight to look for any oil leaks from the engine or transmission.
Finally, you are taking a significant risk by buying a high-mileage diesel vehicle. So ask the previous owners for service and maintenance records. But do not let it be a deal-breaker if they are not able to produce the documents.
Also read: Why are Diesel Oil Changes so Expensive? (Explained)
What are the Most and Least Reliable Diesel Engines with 200k Miles?
Most reliable diesel engines
- 6.7-liter Cummins V8
It has been in production since 2007. It is used in heavy-duty trucks such as Ram 2500.
- 6.7-liter Powerstroke V8
It has been in production since 2011. It is used in the Ford F-250 and the F-350.
- 6.6-liter Duramax L5P V8
It has been in production since 2017. It is used in the GMC Sierra and Chevrolet Silverado.
Least reliable diesel engines
- 2003-2007 Ford Super Duty 6.0-liter V8
- 1982-1992 Chevrolet 6.2-liter V8
- 1978-1981 Chevrolet 5.7-liter V8
How Should You Take Care of a Diesel with 200k?
Big diesel trucks are often used off-road and in muddy conditions. As a result, dirt will get collected on the components, which will cause its corrosion over a while. A little bit of rust that was left unattended can expand over time and render the whole vehicle undrivable. So you must clean the components regularly.
Replace all the filters at regular intervals. This includes the air, oil, and fuel filters. The gradual build-up of grime in the filters can cause the engine to suffocate or burn impurities which will harm the engine.
Keep an eye on your fluid levels. The engine and transmission fluids should be changed at regular intervals. The coolant level should be maintained at the optimum level at all times.