Nov 25, 2019 Turbo Direct, Chris Kambouris, turbocharger life and maintenance
How to care for your turbo and prolong its life
Things the vehicle manufacturers won’t tell you about your turbo by Chris Kambouris, Managing Director, Turbo Direct
Turbochargers are critical components to an engine’s reliable operation, correct emission production, and under bonnet thermal management. The turbocharger, although situated outside the engine, is fed the same oil as the engine from the very same engines oil pump. The oil is fed through an oil feed line, which is the main “artery” feeding the life blood to the turbocharger.
When an engine fails for example - the entire engine is disassembled, and checked for the cause of failure, this failure mechanism is resolved/replaced, and then the engine is reassembled. Most engine rebuilds involve a new oil pump - being the main cause of engine failure, besides wear of the rings, valve seats, valve stem seals etc., this relatively affordable component normally ensures a new life span of the engine.
When a turbocharger fails, because it is situated outside of the engine, it is normally treated as an alternator or starter motor, and removed, replaced or repaired, and re-installed. The vehicle owner normally expects a newly replaced turbocharger to have had its life renewed and expects to see a further 100 000+ kms service from the new component. In reality this is not how it works, the turbocharger is a component that operates at enormous rotational speeds, often in excess of 120 000Rpm, and operates at temperatures above 650degC in normal operating conditions. The latest Euro5/6 engines turbochargers are manufactured with exotic materials and operate above 850DegC
Just because the turbocharger is physically installed outside of the engine, when it fails, it is imperative to treat it as if you were treating an engine rebuild - the most important step to ensuring a renewed service life from a turbocharger that is being replaced is to firstly find the cause of failure, correct this mechanism, and then repair/replace the turbocharger and re-install.
Some of the common questions surrounding turbochargers that we face on a daily basis are:
• How does one know when a turbocharger is about to pack up?
• What sort of life expectancy can I expect from a turbocharger?
• Turbochargers are expensive components, and often pack up without warning, how does one budget for such a failure?
• How do I service and look after my turbocharger?
In short - a turbocharger is an extremely reliable component, it will last as long as your engines life, the manufacturers design turbochargers to exceed 300 000km’s in terms of service in a single lifecycle, however many turbochargers don't see this due to engine maintenance related issues. Lack of maintenance, late maintenance, incomplete maintenance will all shorten the life of your turbocharger, however on the contrary, correct, timeous maintenance will increase the life of your turbocharger. There are 4 main “killers” of turbochargers which are easily able to be addressed and managed, in order to protect and prolong your turbochargers life, these are never mentioned to you by any vehicle manufacturers, or garages. Most mechanics aren't even aware of these tips and tricks.
The following are the 4 “big killers” of turbochargers: -
1. Lack of lubrication
2. Oil contamination (many different types of contamination exist)
3. Foreign object damage (Debris impact)
4. Exceptional operating conditions (Often related to intentional changes or modifications)
Lack of lubrication is simply oil starvation to the turbocharger, this is normally caused by a blocked oil feed line - over time the line that is routed very close to the extremely hot turbine side of the turbocharger, will experience high thermal loads when the engine is shut down after the engine is switched off. While the engine is off, there is no longer oil flow through the turbocharger, and the stagnant oil inside the oil feed line will heat up through heat soak, coming from the 600degC + turbine housing next to it, and the remaining oil inside the thin oil feed line which is made from steel tubing, will burn and coke up inside the line. This is a carbon build up which over time will act just like Cholesterol and start to restrict oil to the turbocharger. Depending on the vehicle - the way round this is through thermal sleeve products which help prevent this, as well as maintenance tips, which relate to replacing this oil feed line at specific mileage/service intervals with a new line. It is not possible to clean these existing lines out.
Oil contamination relates to not just “dirty oil” but instead variations of contaminants, which include water, fuel, debris and TDS (total dissolved solids) aka fine particle debris. Water and fuel contamination will break the oils film strength down and will compromise the oils ability to lubricate the bearing components. In layman terms this means that the oils film is no longer strong enough to prevent metal to metal contact between the bearings and the internal turbocharger parts. This will allow gradual and progressive cause wear to the bearing components, which depends on operation, severity and application it might last from 10km’s in distance to 6 months’ worth of use before the turbocharger eventually generates enough clearance in the bearing system to allow the rotating blades (wheels) to make contact with the end housings - this will result in a catastrophic failure, and often results in massive smoke generated behind the vehicle as oil leaks out the turbocharger and is burned in the turbine housing. Debris in the form of large and fine particle contamination, will simply score, and abnormally wear the bearing components inside the turbocharger and the result will be the same as the above example, making contact with end housings.
Foreign object damage (FOD) is easily visible and more often experienced on the compressor, aluminum, or the cold side of the turbocharger as opposed to the turbine side, however the turbine does experience FOD. This is simply explained as foreign debris being ingested through the air intake tract and contacting the high-speed aluminum compressor wheel. A worn, old air filter is usually the cause of the damage, or an installation, mishap where a mechanic has left a nut or bolt inside of the intake pipes, which then gets drawn into the rotating blades at startup, this will cause this failure. Previous catastrophic turbocharger failures where the previous turbocharger has burst, leaving debris inside the intake tract will also cause this problem. On the turbine side of the turbocharger FOD occurs with a similar installation mishap where once more a bolt, nut or socket falls into the manifold (without the mechanic knowing) at startup the part or debris is sucked into the turbine blades. Other causes of this relate to a broken valve seat, or valve guide, or a burned piston - which is forced in its melted form out the exhaust and into the turbocharger’s turbine stage making contact with the turbine wheel blades.
Exceptional operating conditions are usually where the turbocharger operates outside of the manufacturers specifications, where the turbo is forced to do so through a burst charge pipe (intercooler air pipe) or hose, or often related to intentional changes or “upgrades” to the vehicle like chip tuning, plug in chips etc. - these changes force the turbocharger to operate at much higher speeds and temperatures, in order to increase the boost and or power of the engine - this is done through adding fuel and boost in most cases, which drastically shorten the life of the turbochargers bearing systems. “Hot shut down” is a term that is used when a turbocharged vehicle is driven hard and shut down immediately after stopping at your destination - this allows the higher thermal loads under the bonnet to soak into the bearing system and oil feed line, drastically shortening the life of the turbocharger.
Maintenance tips:
1. Service your vehicle on time every time
2. Use only genuine parts including oil filters, air filters and the correct grade of oil (check the owner’s manual for this, there is a very specific reason for this.)
3. Allow the engine to idle for a short while to stabilize temperatures before shutting off the engine or drive the last few km’s of your journey slowly, and “off boost” to allow air flow to start to cool down the engine and turbo before you arrive at your destination.
4. Start up and warm up is equally important let the engine idle for a while to reach normal running temperature or drive a few km’s off the boost.
5. Replace the oil fee line at specific intervals depending on the vehicle make and application - VW diesels, around 90-100k kms, most French cars at around 65-80k kms, German marques (BMW, Merc, Audi etc.) at around 100-120k kms as a preventative measure.
6. When replacing a turbocharger always replace the oil feed line, oil, oil filter, air filter.
7. Regularly check the operation of the PCV valve and DPF as well as the EGR valve in your car, as these have a direct effect on the reliable operation of the turbocharger.
8. If your engine has a worn engine (blow by past the rings) your turbocharger will give you problems.
9. Make sure the engines breathers are not blocked, blocked breathers will cause a turbocharger to “leak oil” and smoke.
TurboDirect S.A are South Africa’s largest performance product importer and manufacturer. With branches in Southern Africa, Madagascar, and Mauritius making them the largest international turbocharger company in Southern Africa
Representing brands like Garrett by Honeywell, Borg Warner, MSD, ARP, NOS, ACE Clutches, DEPO electronic gauges, Simpson Race Products, their own in-house range of intercoolers, AEM Fuel Pumps and other electronic products, In-house manufactured and CNC machined Billet compressor wheels, and hand-built custom-made Hybrid turbochargers using both Garrett and TurboDirect components.
For more information call Tel. 011 392 5195 or e-mail Christ on info@turbodirect.co.zaOr visit the website www.turbodirect.co.za. Trade enquiries welcomed.
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