Does Your Truck Have a Blown Diesel Turbo? Here’s How to Know

Does your diesel truck have a turbocharger? If so, it’s possible for it to fail (aka “blow”). You may have had a colleague with this problem. Or if you operate a fleet of diesel trucks, it may have occurred in the past.

Here’s what you need to know about diesel turbo malfunction. When you know what causes it, you can work to prevent this problem in your vehicle. Plus, recognizing the signs of a blown diesel turbo will help you get the truck to your mechanic quickly to minimize engine damage and more expensive repairs.

Image by Jan Barkmann from Pixabay

What Is a Blown Diesel Turbo?

The function of the turbocharger

Before we get into turbo failure, it’s important to understand the role of the turbocharger in relation to the engine first.

The turbo takes exhaust gas and recycles it through a turbine wheel. The air becomes compressed and more dense, supercharging the combustion reaction. More fuel can be burned, which increases the vehicle’s power. Fuel efficiency is often boosted as well.

Because diesel engines rely on compressed air (vs. spark plugs) for combustion, a turbocharger can increase engine power even more than with a gasoline-powered vehicle.

What happens when a turbo blows on a diesel?

A blown turbo is essentially a turbo that stops working. While this component is typically quite reliable, it is possible to fail.

What causes diesel turbo failure?

A blown turbo in a diesel truck is frequently due to a lubrication issue. Oil from the engine is used to lubricate the shaft around which the turbo spins. When the turbo becomes starved for oil, it experiences excessive friction. The parts of the turbo — especially the main shaft — can become worn and/or stuck very quickly, causing the turbocharger to fail completely.

How does the turbo lose its oil supply?

  • Leaks
  • Clogged feed lines
  • Poor maintenance

The above scenario is very common with some of the older and high-mileage diesel trucks we see here in Nanaimo, BC.

There are other issues that can cause a diesel turbo to fail, though, with newer and more complex trucks. Those include:

  • Broken electric motor actuator or solenoid
  • Worn unison rings on the turbo interior
  • Excessive buildup inside the exhaust

Blown Turbo Symptoms in Diesel Trucks

How do you know if you have a blown turbo in your diesel truck? A sudden or constantly worsening loss of power is one red flag. You may find it impossible to maintain high speeds, or the response is noticeably sluggish when accelerating.

Another calling card of a blown turbo is a significant drop in fuel economy. Sometimes these signs come on gradually over time, meaning the turbo is on its way to breaking down. But it’s possible for them to appear out of the blue as well.

A blown turbo will also typically be accompanied by whirring, whining, shrieking, or whistling noises. Blue or grey smoke may emanate from the exhaust too. Nearly always, the “check engine” light will illuminate on your dashboard instrument panel.

Does your diesel truck have a boost gauge that shows the effect of your turbo? It should show lower pressure if the turbocharger blows. (Decreased pressure without any of the other signs described above, however, is more likely to be due to another problem.)

Can You Drive a Diesel Truck with a Blown Turbo?

You can drive short distances if your diesel turbo blows, but it’s not advisable to keep driving the vehicle for long like this. That’s because it can cause engine damage. In fact, the turbo blade (impeller) could get pulled into your intercooler or catalytic converter — a situation you definitely want to avoid.

It’s worth noting here that if, instead of a diesel truck, you drive a Mercedes-Benz Sprinter van with an optional turbo, it should go into Limp Mode if the turbo fails. This is a protective mechanism that keeps you from driving at high speeds until the problem is remedied.

Your best course of action is to head to your diesel mechanic as soon as possible. There, the shop will determine if the turbo itself is blown or if it’s another issue.

If the turbo is indeed blown, it will need to be replaced. The upside to this expense is you can upgrade your turbocharger and get the benefit of the very latest technology in the newest models. And you’ll know the turbo is new, so it should last for a long time.

Of course, regular maintenance to prevent a repeat turbo failure is vital. Your mechanic should be able to identify why the turbo blew in the first place, so you can prevent a recurrence. Routine maintenance not only keeps parts going longer but also lets your mechanic catch small problems before they turn into larger, more expensive ones.