Not enough attention is being paid to the impact of blocked diesel particulate filters (DPFs) on turbochargers, says Tom Wright, our product manager.

If technicians don’t check for a DPF issue when installing a replacement turbo, it could lead to the untimely failure of the new turbo, Wright warns. All diesel-powered vehicles manufactured since late 2009 feature a DPF, which is designed to capture soot and remove it from the exhaust gas as the vehicle is driven. To keep the DPF working efficiently, regeneration processes are employed to burn off any excess soot.

However, there are many factors that can stop these regeneration processes from working effectively, such as the type of fuel and oil used, driving style, vehicle age and mileage. Vehicles that are regularly driven on short or low-speed journeys often don’t reach the required temperatures to activate the regeneration process.

“Blockages prevent exhaust gasses passing through the exhaust system at the required rate, which can cause increased exhaust gas temperature and back pressure,” Wright says. “This can affect the turbocharger in a number of ways, ranging from oil leaks and performance degradation to component failure.”

Increased back pressure forces the exhaust gas through the piston ring seals and into the turbo core assembly (CHRA), leading to excessive temperatures, within the CHRA. This prevents efficient oil cooling within the CHRA, and can even carbonise the oil, restricting oil feeds and causing wear to the bearing systems particularly on the hot side of the turbo. These high temperatures can also lead to failure of the turbine wheel through high cycle fatigue.

A blocked DPF can force exhaust gas through the smallest of gaps, including the clearances in the bearing housing variable nozzle turbine (VNT) lever arm and turbine housing wastegate mechanisms. If this happens, carbon build up can restrict movement of the levers, affecting performance of the turbo. Oil leaks into the compressor housing may also occur as a consequence of exhaust gas forcing its way into the CHRA from the turbine side and forcing oil through the oil seal on the compressor side.

“It is critical that any DPF issues are identified and rectified prior to installing a replacement turbocharger,” says Wright. “Failure to address the original problem means the replacement turbo will be subjected to the same operating environment as the previous unit, and will ultimately suffer the same failure in a significantly shorter amount of time.”

 

For more information on us, including technical resources or how to find your nearest turbo specialist, please visit: https://www.melett.com/technical/

There is no better time to offer a remanufactured turbocharger to customers as the current economic climate has led to a perfect storm for vehicle owners.

From a customer viewpoint, remanufactured products using high-quality components can be considered the same as a new product, providing a more attractively priced alternative to the original.

Turbocharger remanufacturing is increasing in popularity within the aftermarket, as an original equipment turbo can often be very expensive to replace. Remanufacturing preserves as much of the material in the original product as possible, therefore using less raw materials than in the manufacture of new products.

Remanufacturing involves vehicle parts being rebuilt to a standard equal to, or greater than, the original manufacturer specification. At times, aftermarket design improvements mean that remanufactured parts often outperform the original equipment (OE) originals, as any design defects can be engineered out.

The process ensures that the original design and quality specifications are all met, so technicians and end users can be confident in the quality of the remanufactured vehicle part they receive.

In the past, low-quality components from unreputable suppliers have been used in the remanufacture of turbochargers, which has created preconceptions about the reliability of remanufactured parts. However, this opinion about remanufacturing has changed significantly in recent years.

A professional turbo repairer will carry out pre-production checks of all old units to ensure that only the best quality turbo core is selected for remanufacturing. All parts are inspected for damage and wear. Any worn or damaged parts will be replaced. The core assembly is balanced and only when a unit passes the final balancing tests is it deemed ready for final assembly.

Tom Wright, product manager said: “The entire UK economy is being gripped by the cost-of-living crisis, and the garage and automotive sector is no exception.”

“With service providers and customers concerned about spending, it’s important to consider the benefits in cost offered by remanufactured components, with significant reductions in price when compared to original equipment (OE) products.

“Cost savings aside, we’re reminding the industry that there’s no compromise on safety and part quality. The use of high-quality components in remanufacture ensures a long-term, sustainable approach on vehicle repair and servicing.”

Automotive Parts Remanufacturers Association (APRA) Europe recently reported that¹ remanufacturing saves millions of tons of carbon equivalent emissions, 85 percent of raw materials and 55 percent of energy compared with new production, meaning remanufacturing is sustainable and resource friendly.

“Remanufacturing provides additional benefits on a wider scale, with the environment benefitting from carbon savings and reduced emissions from not having to extract raw materials in the manufacturing process of a new turbocharger,” Wright says.

At Melett, we understand the importance of using the correct materials and are committed to supporting the turbocharger repair market with the highest quality parts and service.

For more information about us, including technical resources or how to find your nearest turbo specialist, click here.

1: APRA Europe, https://apraeurope.org/?method=ical&id=1920

Oil leaks can be caused by several factors, but technicians shouldn’t rush to remove the turbocharger in the event of a leak to diagnose a fault, says Product Manager, Tom Wright.

There can be a variety of reasons why a turbocharger may leak oil with the main factor being incorrect pressure within the compressor and turbine housings. “Before removing the turbo, technicians should check the location of the oil leak as different diagnoses can be given depending on which end the leak is located. Over 90 percent of turbocharger failures are consequential of other issues, so identifying the root cause before replacing a turbo is key.” says Wright.

When looking for causes of oil leaks at the compressor end of the turbocharger, a good place to start would be to inspect the air intake hose for damage, splits, leaks and incorrect fitment. At the turbine end, oil leaks can be caused by warped exhaust flanges, incorrect gaskets, or cracks in the turbine housing – something that is sometimes only visible when the turbo is hot.

If there is a kink, bend, or partial blockage in the oil return pipe, this will cause the oil pressure to build up in the bearing housing, resulting in leaks from both turbine and compressor ends.

It is worth noting that removal of intake or exhaust pipes to inspect the turbocharger for oil leaks will cause leaks to occur. In doing so, you inherently cause a pressure drop which allows oil to leak from the turbocharger.

To prevent oil leaks when fitting a turbocharger, technicians should ensure that the air systems and oil drain systems are clear from any blockages. They should always fit the correct oil gaskets for the turbocharger. They are also advised to not use silicone in an attempt to seal oil inlet and oil outlets. Silicone can become easily dislodged and can restrict or block oil passages as a result.

Technicians working on turbochargers should also check the vehicle’s exhaust system, including the diesel particulate filter and catalytic converter, to make sure no leaks or blockages are present.

Using the correct parts and high-quality equipment is crucial to successful turbocharger maintenance.

Melett is renowned for producing OE quality products to help the turbo aftermarket produce the highest quality repairs. All Melett turbochargers are built, balanced and flow tested in the UK to the strictest quality standards to ensure OE performance during operation.

To help identify common failures in warranty situations and to provide advice on how to prevent future failures occurring, check out our series of educational technical videos.

What is overspeeding and why does it damage turbos?

Overspeeding is a term used when a turbo is operating well above its normal operating limits, and the resultant strain of overspeeding can cause untimely failure of the turbo, as well as the internal combustion engine (ICE) and associated components, Tom Wright, our product manager warns.

One of the main causes of overspeeding is insufficient airflow from the turbocharger to the engine, which could be caused by a torn air pipe, a blocked air intake or a leak between the compressor and the engine. If there are any leaks, cracks or poor seals between the compressor and the engine, the turbo will have to work much harder than it should to deliver the required air levels to the engine.

“When the engine needs more air than the turbocharger can supply, overspeeding occurs. The turbocharger then has to work outside of its usual operating limits which can, in extreme cases, cause blade damage including partial loss of blades, fatigue fractures or a burst compressor wheel,” says Wright.

A common symptom of overspeeding is the presence of the ‘orange peel’ effect on the back face of the compressor wheel. This is created by expansion and contraction.

When the compressor wheel is subjected to overspeeding, it grows in size and this expansion causes cracks between the grain boundaries of the material.

In mild cases, the component will return to its original state like elastic but in most cases these cracks begin to grow and eventually, part of the hub can break away.

Another cause of turbo overspeeding can be remapping the electronic control unit (ECU). As drivers of some performance vehicles look to maximise the fuel efficiency or performance of their cars, some turn to remapping or ‘chipped’ engine work, which involves altering the car’s ECU to deliver a different power map or torque range. This can then take the standard factory fitted turbocharger outside the operating range it was design to work within.

Wright advises when diagnosing a turbocharger fault, technicians should be wary that as a consequence of overspeeding the signs of other failure modes such as insufficient lubrication can be present. This is due to the barrier created by the oil film within the bearing systems failing. In turn, this causes contact between components as overspeeding occurs and the turbo fails.

For more information on overspeeding and the preventative measures you can take, visit our dedicated technical article: Common turbo failure – Overspeeding. You can also check out our series of educational technical videos which help identify common failures in warranty situations and provide advice on how to prevent future failures occurring,

In the winter months, don’t forget to think turbo!

As the trusted aftermarket brand for precision engineered turbochargers and parts, we’re urging technicians to stay on top of turbo maintenance this winter and are offering best practice tips to help customers prolong the life of their turbo as temperatures plummet.

Lubrication is a key element to ensuring a turbocharger is doing its job correctly. Therefore, it is essential to check that a vehicle’s oil is the correct grade. When fitting a replacement turbo, it is important that the oil system has been primed and is in full working order. If this is not the case, it can lead to premature failure.

Many turbo-related issues are simply down to neglect, and with more than a third of drivers expected to skip servicing their vehicle in a poll[1] taken in 2022, we’re advising technicians to not only encourage regular servicing, but also to ensure the vehicle’s oil and oil filter is checked and replaced to protect the turbo from damage caused by contamination.

Another top tip for motorists is to adapt their driving habits during the colder weather, especially if the vehicle has not been run for long periods. Simple changes such as waiting a few minutes before driving at high revs to allow the engine to warm and oil to flow through the turbocharger. This prevents damage to components within the turbocharger. By avoiding revving the engine, unnecessary stress on the turbo is avoided.

For more turbo tips and helpful video resources, please visit www.melett.com/technical

[1] https://www.thisismoney.co.uk/money/cars/article-11511699/Third-drivers-likely-delay-skip-cars-service-save-money.html