overheating PORSCHE 911 GT3 2004 5.G Owners Manual

•Brakewarning lightUSA
~ Brakewarning lightCanada

If the warning lightsinthe instrument panelandon-
board computer goonwhile driving, thebrake flu-
id level maybetoo low, or(ifthe brake pedaltrav-
el has increased) oneofthe two brake circuits
may have failed.
A greater braking pressure willberequired, stop-
ping distances willbelonger andthebraking be-
havior willchange, particularly incurves.
With correctly adjustedbrakes,andacorrectly
working brakesystem, thepedal travel tothe
point ofbrake actuation shouldbe1-3/16 in.to
1-9/16 in.or30 to40 mm.
Whenever thebrake pedaltravel exceeds thisdis-
tance, havethebrake system checked.

42
Controls, Instruments
Brake
pedal

A
Warning!
Risk ofan accident.
Any obstruction ofthe brake pedalcould
increase thestopping distance.

~ Always checkthemovement ofthe brake ped-
al before driving andmake surethatitis not
obstructed byafloor matorany other object.
~ Secure thefloor mattoprevent itfrom sliding
into positions thatcould interfere withthesafe
operation ofyour vehicle.
Your Porsche dealerwillbeglad tooffer you
floor mats ofthe correct sizeincluding asecur-
ing possibility.

Note

In case oneofthe two brake circuits fails,in-
creased pedaltravel isrequired tobring your
vehicle toafull stop.
A

Warning!
To avoid overheating andpremature wearof
the brakes:

~ Before descending asteep grade, reduce
speed andshift thetransmission intoalower
gear ordriving position tocontrol speed.
~ Donot "ride thebrakes" byresting yourfooton
the pedal whennotintending toapply brake
pressure.
~ Donot hold thepedal downtoolong ortoo
often.
This could cause thebrakes toget hotand not
function properly.

HowEmission ControlWorks

When anautomobile engineisrunning, ituses en-
ergy generated throughthecombustion ofamix-
ture ofair and fuel. Depending onwhether acar is
driven fastorslowly orwhether theengine iscold
or hot, some ofthe fuel (hydrocarbons) maynot
be burned completely, butmay bedischarged into
the engine crankcase orexhaust system.Additon-
al hydrocarbons mayenter theatmosphere
through evaporation offuel from thefuel tank.
These hydrocarbons
(He),
when released intothe
air, contribute toundesirable pollution.
In addition, carbonmonoxide (CO)andoxides of
nitrogen (NOx)contribute toengine emissions.
They, too,areformed duringthecombustion pro-
cess anddischarged intotheexhaust system.
To reduce thesepollutants, yourPorsche is
equipped withaprecisely calibrated fuelinjection
system toassure afinely balanced air/fuelmixture
under alloperating conditions.
Oxygen
sensor

The oxygen sensor, installed inthe exhaust pipe
continuously sensestheoxygen content ofthe
exhaust andsignals theinformation toan electron-
ic control unit.Thecontrol unitcorrects theair/
fuel ratio, sothe engine always receives anaccu-
rately metered air/fuelmixture.

Crankcase ventilation

Through crankcase ventilation, undesirable emis-
sions fromtheengine crankcase arenotpermit-
ted toreach theoutside atmosphere. Theseemis-
sions arerecirculated fromthecrankcase tothe
air intake system. Fromheretheemissions mix
with theintake airand arelater burned inthe en-
gine.

Catalytic converters

The catalytic converters areefficient "clean-up"
devices builtintotheexhaust systemofthe vehi-
cle. The catalytic converters burntheundesirable
pollutants inthe exhaust gasbefore itis released
into theatmosphere.

The exclusive useofunleaded fueliscritical-
ly important forthe lifeofthe catalytic con-
verters. Therefore, onlyunleaded fuelmust
be used. The
catalytic converters willbedamaged by:

- push ortow starting thevehicle
- misfiring ofthe engine
- turning offthe ignition whilethevehicle ismov-
ing or
- driving untilthefuel tank iscompletely empty
- byother unusual operating conditions.

t>
Donot continue tooperate yourvehicle under
these conditions, sincerawfuelmight reach
the catalytic converters. Thiscould result in
overheating ofthe converters. Federallawpro-
hibits useofleaded fuelinthis car.
Maintenance, CarCare
125