Text Size

Unscrupulous Turbo "Repairers"

This insight script serves to provide the public with the skewed, absolutely false and misleading turbocharger failure reports that are being written by the so called “turbocharger specialists” in the market today. Below is a report written by a local company in the centurion area claiming to be a turbocharger expert, the scary part of this is that this company is registered with RMI  -

This document below is the actual report provided to a customer who took his vehicle to this uncscrupulous "turbo repairer" and after it failed when the "repairer" used chinese parts, this is the resulting report written by that "repairer". You will see comments in RED, these are our comments in responce to the incorrect, reported information in black. 

SUSPECTED CAUSE OF TURBOCHARGER FAILURE:

1.) Background

i) A faulty turbocharger was replaced with a new one the said vehicle in October 2011.

ii) Customer complained about an oil-leak from the engine-area during January 2012.

iii) Repairer advised customer to bring the vehicle back to its Mechanical workshop as soon as possible. Customer found it difficult to bring vehicle back during the week, and preferred to bring vehicle on a Saturday. Since Repairer’ Mechanical workshop is mostly non-operational on Saturdays, an arrangement was made for customer to bring the said vehicle on a particular Saturday. Customer did not bring vehicle on appointed time.

2.) Evaluation

i) The said vehicle was finally inspected by Repairer on 8 August 2012, when the Repairer Mechanic explained to Customer that the vehicle has engine blow-by. Excessive oil-deposits inside the breather-pipe was pointed out to Customer.

ii) Turbocharger shows fatigue failure and blade damage of compressor wheel and blade damage on turbine wheel.

iii) Metal-on-metal contact (between journal-bearing and turbine-shaft) caused the turbine shaft to break.

iv) “Orange peel” effect on back face of compressor wheel is a clear sign of over-speeding.

3.) Conclusion

i) Turbocharger shows clear signs of cyclic over-speeding.

ii) Severe engine-blow-by was detected a week prior to turbocharger failure.

iii) Engine blow-by (typically caused by worn piston-rings), causes oil to seep into combustion-chamber.

iv) Engine blow-by also causes oil from the sump to push via the oil ports and escape via the breather-pipe, into the air-intake pipe, through the turbocharger, into the inter-cooler and when the inter-cooler has filled up enough, all this oil gets pushed (via the boost-path) directly into the combustion chamber.

v) Finally, when there is enough oil inside the combustion chamber, the oil/diesel mixture ignites, causing the engine to “run away”, causing turbocharger over-speed and destruction of the turbocharger. This might also cause engine-damage.

repairfail1

repairfail2

repairfail3

1.) Background i) A faulty turbocharger was replaced with a new one in October 2011.

ii) Customer complained about an oil leak from the engine area during January 2012. After checking with the vehicle owner, the oil leak was reported to have occurred on top of the turbocharger.  It was identified as having been from the oil feed line entering the turbocharger which was never installed correctly.

iii) Repairer advised customer to bring the vehicle back to its Mechanical workshop as soon as possible. Customer found it difficult to bring vehicle back during the week, and preferred to bring vehicle on a Saturday. Since Repairer’ Mechanical workshop is mostly non-operational on Saturdays, an arrangement was made for customer to bring the said vehicle on a particular Saturday. Customer did not bring vehicle on appointed time.

2.) Evaluation i) The said vehicle was finally inspected by Repairer on 8 August 2012.  The Repairer’s Mechanic explained to Customer that the vehicle had evidence of engine ‘blow-by’. Excessive oil-deposits inside the breather-pipe were pointed out to Customer. Oil deposits may have no relation to engine blow by, in fact a brand new turbo diesel engine during operation may have oil deposits inside the breather pipe – as the breather pipes are OIL breathers, and potentially carry oil vapor from inside the engine. The correct procedure to ascertain whether an engine has blow-by, would be to perform a leak down test and a compression test of which none were carried out.

ii) “Turbocharger shows fatigue failure and blade damage of compressor wheel and blade damage on turbine wheel”. Let’s address each comment individually with information and facts supporting each statement.

 

  1. 1.Fatigue failure:- This comment is absolute hog-wash – a fatigue failure can only be observed from a fracture surface i.e fracturedThe compressor wheel has not failed, nor has it burst, nor has it fractured in any way or form, which would allow for a visual evaluation and/or the use of scanning electron microscopy to verify such a statement.  If there was evidence of a fatigue failure, striations would be present and the resulting fracture morphology would confirm the regime under which the fatigue crack(s) had propagated (high/low cycle). It would then and only then be possible to conclude the resulting nature of the failure mechanism responsible for the demise of the specific item being evaluated (which in most instances is completely un-related to the initial mechanism responsible for the destruction of the turbocharger in question).  This centurion based ‘turbocharger specialist’ clearly has no idea what they are talking about, and has irresponsibly used technical jargon (common to fault finding literature supplied to outlets) to mislead the public!
  2. 2.The compressor wheel blade damage is clearly visible given the burrs and the direction in which they are orientated relative to the plastic deformation associated with the failure mechanism. The compressor wheel in this turbocharger rotates in a clockwise direction – the rest is visible by the pictures provided above.
  1. The turbine wheel has also sustained damage – this is also clear to see in the pictures above – however please note which part of the turbine wheel is damaged.  Of greater importance is the reaction markings on the turbine shaft itself, and the position thereof.  The most severe being the area closest to the turbine head (discussed hereafter). The turbine wheel blades indeed have made contact with something in the turbine housing assembly – however it cannot be verified as to what exactly, from photographic representation alone (Energy Dispersive X-ray (EDX) analysis during Scanning Electron Microscopy is generally utilized in such instances).

iii) Metal-on-metal contact (between journal-bearing and turbine-shaft) caused the turbine shaft to break.

  1. 1.Material-to-Material contact is visible according to the above pictures, however this is in no way the cause of the turbine shaft failure at the shoulder. In general for a turbine shaft failure to occur at either the head or neck area region, the resulting mechanism would have been preceded by a ‘lubrication failure’ (i.e. lack of lubrication and/or contamination thereof) or some other catastrophicThe material transfer present on the turbine wheel’s load bearing regions (running faces) are witness to a seizure mechanism in the absence of suitable lubrication (volume and/or condition thereof).  The bearing materials in this turbocharger are made from a grade of bronze, and the turbine shaft a hardened alloy steel. The absence of suitable lubrication at the high rotational speeds (excess of 100 000rpm) would facilitate the onset of a seizure mechanism, where-buy the resulting thermal loads cause the two materials the metallurgically bond (friction weld), however the continued rotational forces and high thermal stresses cause the weaker of the two materials to fracture under-load and hence the resulting transfer of material associated with seizure. The most common and/or catastrophic cause of material transfer under bearing applications is a total lack of lubrication.  There are however numerous causes of seizure which are not pertinent to this specific failure. To set the record straight – the material transfer and/or sezure is directly associated with a lack of lubrication, and had subsequently facilitated the failure of the shaft (hence one mechanism leading into the next). There are many causes for the lack of lubrication, which I will provide to you in the conclusion of this report. 

 

iv) “Orange peel” effect on back face of the compressor wheel is a clear sign of over-speeding.

  1. 1.This is the most humorous and yet false statement of all of the above, I must laugh the writer of this report - for writing this comment, as not only is it irrelevant to this failure, but also the condition that the compressor wheel is in, is not able to allow you to even see orange peel. Metallurgical equipment which TurboDirect are the only turbocharger company in Africa to own, is able to verify suchphenomenon, and in addition thereto such equipment is required to verify whether or not the metallurgical structure of the compressor wheel has been altered or not. Orange peel is a term used to describe the surface appearance of a component (most distinguishable in aluminum components) which has been subjected to excessive operating conditions (strain), in this instance being the centrifugal forces associated with the high rotational stresses.  To identify the reported orange-peel effect one would require an un-tarnished or damaged surface within the region of inherently high stress concentration. Inspection of the wheel revealed no such damage given the shielding effect of the secondary damage sustained to the wheel as evidence by the severely scrubbed and scored face. It would also mean that the ECU on the vehicle would have been modified in a way that the boost was increased beyond a specific level in order to allow the rotating assembly to exceed the compressor wheels ability to withstand the centrifugal forces and hence the resulting over-stress, this would have been present in the rotating assembly aswell. The fact that the turbocharger lasted as long as it did, is also testament to the fact that there was no over speeding as this would have caused the turbocharger to have failed within minutes of its installation, compounded specifically by the lubrication problem in the vehicle.

 

3.) Conclusion i) Turbocharger shows clear signs of cyclic over-speeding. Not possible and irrelevant – the failure is a lubrication failure alone.

ii) Severe engine-blow-by was detected a week prior to turbocharger failure. False – no tests were carried out to verify this, nor will engine ‘blow-by’ result in a lack of lubrication to the turbocharger without prior warning from the engine’s operating systems (given the number of sensors regulating the oil supply).

iii) Engine blow-by (typically caused by worn piston-rings), causes oil to seep into combustion-chamber. This comment is false – engine blow by will pressurize the sump as the pressure inside the cylinder is much higher than the pressure in the lower part of the engine, this will in-turn prevent the turbocharger from draining its oil back into the engine’s sump, causing the vehicle to smoke excessively – this was never the case nor were any of the symptoms associated thereto.

iv) Engine blow-by also causes oil from the sump to push via the oil ports and escape via the breather-pipe, into the air-intake pipe, through the turbocharger, into the inter-cooler and when the inter-cooler has filled up enough, all this oil gets pushed (via the boost-path) directly into the combustion chamber. Absolute rubbish – if the pressurized sump prevented oil from passing through the oil ports and galleries, the engine would have failed as no oil would have reached the crankshaft, main bearings, big end bearing etc (in addition thereto numerous sensors and systems would have detected such an occurrence within the engine) If there was oil forced by any means through the intercooler into the engine, there would have been excessive smoking as the oil is burned in the engine – this was never the case!  The engine management system would have detected the presence of the unfavorable combustion gasses resulting from the lubrication being forced into the combustion cycle.  One of the detection systems is required to protect the catalytical convertor and prevent the destruction thereof (the basic function and details of the inner operating systems of a modern combustion engine would required several days to convey into laymen’s terms and we will not bore you with such information at this point).  It does however concern us that many suppliers and service providers in our market have no knowledge of such systems, and make ridiculous comments about vehicle they know little or nothing about – YET they call themselves experts and specialists!! BEWARE OF THESE UNSCRUPULOUS COMPANIES!!!

v) Finally, when there is enough oil inside the combustion chamber, the oil/diesel mixture ignites, causing the engine to “run away”, causing turbocharger over-speed and destruction of the turbocharger. This might also cause engine-damage. False once again – an engine run away will not cause any turbocharger failure, as the VNT mechanism on this specific turbocharger is controlled by the ECU and the sensors referenced by the ECU are threefold in this case, EGT (exhaust gas temperature), engine temperature, MAP (manifold pressure) – if anyone of these run away, the VNT mechanism will either open or close to achieve minimum flow, saving the turbocharger. Secondly – the customer confirms that the engine never ran away, the car was driving until the failure. On a lighter side, if this was possible we would be the first to harness the amazing combustion enhancing benefits of ‘blow-by’ for our performance vehicles.  Oh and if you have any old oil lying around please send it to us, apparently it runs better than diesel!!

Correct conclusion:-

 The demise of the above turbocharger was clearly due to lack of lubrication, however this was a two stage failure – in the absence of lubrication, the materials will transfer once the thermal ceiling is reached – the seizure of the rotating assembly at rotating speeds with allow the compressor to carry its momentum and transfer this energy through the shaft breaking it at its weakest point – the shoulder – this is the second stage. The oil feed line was never replaced, nor was the sump removed or the oil pump replaced/checked for operating oil pressures according to correct procedures for the said turbocharger/engine application. There is a specific procedure in which to follow depending on the vehicles mileage to verify the oil pressure, and lubrication flow characteristics of the engine – if followed, the turbocharger would have been operational today.

 Recomendations:- 

BEFORE replacing the turbocharger with a brand new genuine part FIRST DETERMINE THE INITIAL FAILURE AND REPAIR THIS FAULT – replace the oil inlet line (do not attempt to clean) replace oil pump according to accredited procedures, check oil pressures according to accredited procedures, carry out sump service and prime check according to accredited procedure including other accredited checks in order to verify and confirm a correct and reliable installation. For further information, contact TurboDirect S.A for these procedures. 

Comments:-

 The writer of this report clearly has had absolutely no official training on turbochargers, or how they operate or fail. TurboDirect are the appointed Honeywell technical face for Garrett, and such are fully trained on all Garrett by Honeywell turbochargers and related products. The basics, most of which have been touched on above in this report are covered in our Level 1 Basic introduction to turbochargers – the above company is unscrupulous and has not even attended a basic level 1 training seminar – yet calls himself an expert and clearly employs untrained technical personnel to carry out work on your vehicle.  If the owner of the company writing the reports has such a lack of knowledge, who trains his employees?

 

 In the above report – 5 failure causes were mentioned – ‘ 

  1. 1.1.Metal on metal contact
  2. 2.2.Cyclic over-speed
  3. 3.3.Fatigue failure
  4. 4.4.Orange peel
  5. 5.5.Engine blow by

 None of these ‘failures’ in this case are relevant or correct – the information is useless and false – this misleading report is why the turbocharger repair industry has such a poor name.

 Contact TurboDirect for a list of reputable turbocharger specialists – accredited by TurboDirect with the relevant training!