Diesel vs petrol engines is a debate that’s been raging for a century. While the two types of engines have similarities, the way they use fuel means they’re suited to very different purposes.
Diesel engines are often found in heavy-duty commercial equipment where they’re expected to run continuously. To ensure they stand up to those harsh conditions, diesel engines are built tough, and that means their lifespan is hard to beat.
Do diesel engines last longer than petrol? In this article, we’re going to find out!
Do Diesel Engines Last Longer?
Diesel engines typically last longer than petrol engines. Diesels use heavy-duty internal components that operate at relatively low Revolutions Per Minute (RPM). While diesels have a high cylinder compression ratio, they’re built tough to withstand the additional pressure.
Here’s how diesel engines and petrol engines compare:
Diesel Engines | Petrol Engines | |
|---|---|---|
Typical Compression Ratio | 20:1 | 12:1 |
Maximum RPM | 3000 - 5000 RPM | 6000 - 8000 RPM |
Typical Lifespan | 500,000 - 1,000,000 km | 200,000 - 300,000 km |
Extend the life of your diesel
If it’s time for a diesel repair service or any other maintenance, get in touch with KS Mobile Diesel!
We’re a team of mobile diesel mechanics based in Caboolture. We service all types of diesel vehicles, including trucks, buses, 4WDs, mining equipment, earthmoving equipment and more.
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How Much Longer Do Diesel Engines Last?
It’s common for diesel engines to last longer than petrol engines, with some models living for 1,000,000 kilometres or more. By contrast, the petrol engines found in passenger cars typically only last for 200,000 kilometres.
Why Do Diesel Engines Last Longer?
Diesel engines last longer because they use a slightly different combustion cycle to petrol engines.
In diesel engines, the pistons are only used to compress air. Compression causes the air to heat up. Once it’s at maximum pressure, atomised diesel fuel is injected into the cylinder and immediately ignites. This drives the piston downwards and generates rotational power.
Compare this to petrol engines, where the pistons are used to compress a mixture of petrol and air. This limits the maximum amount of compression that can be achieved before the petrol autoignites. It’s important to avoid autoignition within an engine, because it reduces the output and fuel efficiency.
Diesel engines contain toughened components that can withstand the amount of power generated under the high-compression environment. This causes them to last significantly longer than petrol engines.
Factors Affecting the Lifespan of Diesel Engines
There are several factors that extend the average lifespan of a diesel engine:
Tips to Prolong the Life of Your Diesel Engine
Like any other engine, diesels need maintenance, and normal use can wear down critical components. If you want to prolong the life of your diesel engine, we have a few simple tips:
The best way to extend the life of a diesel engine is to regularly change the oil and check the fuel. Degrading engine oil and contaminated fuel are two of the biggest killers of diesel engines, so staying on top of those issues can help you avoid the worst!