Reasons for Turbo Failureby Don Kress
Turbocharged engines can be fun to drive, particularly if the turbo is fitted onto a car which wasn't originally equipped with a turbocharged engine. The downside is that turbochargers require meticulous care and almost constant maintenance, particularly in high-boost engine applications. If caught early, the more common problems associated with turbochargers -- before catastrophic failure of the turbo impeller -- are fixable, and the turbocharger can generally be saved. Driven too long without maintenance, however, the turbocharger housing can actually break apart, necessitating the replacement of the entire turbocharger.
Overheating/ Bearing Damage
Turbochargers are prone to overheating, and not just under high-performance driving conditions. Because the turbo utilizes exhaust air to drive the impeller and pack air into the intake track, it has the potential to run at least as hot as the engine itself, and sometimes hotter due to the extreme pressure exerted on the turbocharger housing. An overworked turbocharger will tend to overheat its own bearings, which in turn will increase the friction against the turbo housing. This is an especially large problem in non-intercooled engines in which the coolant and oil are not regularly changed. Because the turbocharger depends on the engine oil to cool it, overheated engine oil due to poorly performing engine coolant can quickly "burn out" the turbo's bearings, eventually freezing the impeller by welding it to the turbocharger housing.
Pressure Loss/ Line or Hose Burst
A particularly easy problem to fix, but one that could leave your turbocharged car limping along the side of the road is the problem of a pressure loss due to a burst line or hose. In many cases, this problem is due to installer error. During the installation process, it can be fairly easy to forget to properly tighten down the compression fittings that hold the turbocharger outlet hose to the vehicle throttle body. This loss of pressure is fixed by reinstalling and properly securing the compression fitting onto the vehicle throttle body.
Obstructed Air Intake
An obstructed air intake can be a significant problem in that it may be some time before the vehicle operator will notice a malfunction. First, a minor pressure loss will be noticed, followed by increased turbocharger noise as it works without the right amount of backpressure from the engine. To fix this issue, remove the air filter from the vehicle and replace it with a new filter, then check the air inlet routing through the core support of the vehicle to ensure that there is no blockage of air flow into the vehicle's air box.
Obstructed Oil Drain Line
In some cases, an obstructed oil drain line may cause overheating in a turbocharger. This happens if the oil is not allowed to circulate through and out of the turbocharger to get cooled off. The turbocharger then overheats, and may possibly seize as described above. The best fix for a clogged oil line is to change the engine oil and remove the oil drain line routed from the turbocharger to the engine oil pan, checking it for steady flow and a lack of blockage. Regular oil changes are the best preventive maintenance for this type of turbocharger damage.
- "Maximum Boost: Designing, Testing, and Installing Turbocharger Systems"; Corky Bell; 1997
- "Street Turbocharging"; Mark Warner; 2006
- "Turbo: Real-World High-Performance Turbocharger Systems"; Jay Miller; 2008
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