Auto Service Professional

OCT 2018

Magazine for the auto service professional

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50 A S P O c t o b e r 2 018 T u r b o S e r v i c e T i p s the upper-most water level in the cooling system in order to provide thermal siphoning and flow of coolant through the turbocharger's bearing housing. Diagnosing If the engine has experienced any issues, such as low oil pressure, low oil volume, sludge buildup, excessive crankcase blow-by, piston ring failure, scored main or rod bearings, mechanical failures that have resulted in metal particles dispersed into the engine, etc., it is highly likely that the turbocharger has been affected. If engine issues have been discovered, do not ignore the turbo- charger. Don't treat the turbo as a "separate accessory." Any issue dealing with lubrication (lack of oil or contamination) directly affects the condition of the turbo. Safety note: If performing an on-vehicle in- spection of the turbocharger, never place your fingers near the turbo compressor inlet if the en- gine is running. Never place anything into or close to the com- pressor with the engine running. e blades of the compressor will act like a wood chipper and will try to eat anything in its path resulting in either severe injury and/or destruction of the compressor blades. With the engine off, remove the compressor's air inlet and inspect the compressor for blade damage. Any deformation, chipping or blade edge erosion is cause for compressor replace- ment. Rotate the sha by hand and feel for any sen- sation of binding or drag. Push the sha to one side (applying lateral pressure) and rotate. Any difference in rotating feel (easy to rotate with no lateral pressure but drags when pushed to one side) is a sign that the turbo needs to be rebuilt or replaced. Axial play in the sha should be in the range of 0.001 – 0.004 in., which would require a dial indicator for checking. However, if you can noticeable feel axial play (in/out) by hand, the thrust bearing is worn, again requiring rebuild or replacement. Also — and this cannot be over-emphasized — when replacing a turbocharger, never allow a dry start. Always make sure that the turbocharg- er is pre-oiled prior to starting the engine. A dry Here's an example of a damaged compressor wheel. Something entered the airstream and quickly chewed up the blades. COURTESY OF HONEYWELL A turbocharger features incredibly tight tolerances. Excess shaft/bearing wear or damage to compressor or turbine fins can result in catastrophic failure. Proper maintenance is critical. COURTESY BORGWARNER Here's a worn turbine shaft, likely caused by insufficient oil delivery or oil condition. COURTESY OF HONEYWELL

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