Reasons for Turbocharger Failure
There are three major reasons for turbocharger failure:
- faulty lubrication,
- excessive condensation,
- and a lack of regularly scheduled maintenance.
Lubrication Failure –
Proper cooling and lubrication are vital to turbocharger operation.
Turbochargers are driven by hot exhaust gases
exiting the combustion chamber and, therefore,
are subject to extreme temperatures. In a Burst
& Containment Document authored by Honeywell , their Garrett Engineering group
provides an operating description of its smallest
turbo product. The article states that the
turbocharger’s impellers operate up to 200,000
rpm and the exhaust gas temperature can reach a
max of 1800°F, causing the turbine housing to
glow red under certain driving conditions.
Circulating engine oil through the turbocharger
to remove heat and provide lubrication to
internal components ensures functional
operation. A lack of lubrication from degraded
engine oil or insufficient delivery from an
obstructed oil line can cause increased friction
and temperatures. In extreme cases of poor
lubrication and high operating temperatures,
moving components can become seized, locking
up the turbocharger and disabling operation of
the vehicle. Excessive Condensation –
Many high performance turbochargers are known for their
variable geometry turbines (VGT or VNT).
These units have controlled vanes, which help
increase or decrease impeller speed within the
turbine’s housing. Seized or sticking vanes
cause performance failures on this type of turbo.
Rust formations on the vanes, created by
excessive condensation build-up when a vehicle
is idle for extended periods of time, is the cause
of failure. Condensation can enter the tail pipe
or an exhaust manifold gasket leak. Typically,
this occurs from irregular or sporadic driving.
Regular on-the-road vehicle use will help burn
condensation and prevent rusting.
Lack of Maintenance –
Turbocharged engines require thorough care with stable, regularly
scheduled maintenance cycles for lubrication
systems, air filters, seals and gaskets. As
previously noted, catastrophic failure can occur
when engine oil changes become infrequent and
fail to meet recommended scheduling intervals.
Air filter maintenance is vital to eliminate
foreign object damage (FOD) to the charged air
impeller. Research shows that under normal
driving conditions, most medium-duty diesel
vehicles have an average operation life of 10
years or 100,000 kilometers on their exhaust systems.
At 100,000 kilometers, inspecting and cleaning the
intercooler system and removing any cause of
FOD is highly recommended. After excessive
miles, turbochargers sometimes experience
pressure loss caused by worn seals (leakage)
and/or worn impeller (leakage). Seals will easily
damage under extensive pressure cycles,
especially sealing rings for rotating parts.
Foreign object damage to impeller, as well as
chipped or bent vanes on impellers, will reduce
required energy efficiency to increase
combustion pressure (power).