2008 Mercury Grand Marquis inflation pressure

12.Treadwear, Traction and Temperature Grades
•Treadwear:The treadwear grade is a comparative rating based on the
wear rate of the tire when tested under controlled conditions on a
specified government test course. For example, a tire graded 150
would wear one and one-half (1
12) times as well on the government
course as a tire graded 100.
•Traction:The traction grades, from highest to lowest are AA, A, B,
and C. The grades represent the tire’s ability to stop on wet pavement
as measured under controlled conditions on specified government test
surfaces of asphalt and concrete. A tire marked C may have poor
traction performance.
•Temperature:The temperature grades are A (the highest), B and C,
representing the tire’s resistance to the generation of heat and its
ability to dissipate heat when tested under controlled conditions on a
specified indoor laboratory test wheel.
13.Maximum Permissible Inflation Pressure:Indicates the tire
manufacturers’ maximum permissible pressure and/or the pressure at
which the maximum load can be carried by the tire. This pressure is
normally higher than the manufacturer’s recommended cold inflation
pressure which can be found on the Safety Compliance Certification
Label or Tire Label which is located on the B-Pillar or the edge of the
driver’s door. The cold inflation pressure should never be set lower than
the recommended pressure on the vehicle label.
The tire suppliers may have additional markings, notes or warnings such
as standard load, radial tubeless, etc.
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
155

Additional information contained on the tire sidewall for “LT” type
tires
“LT” type tires have some additional
information beyond those of “P”
type tires; these differences are
described below:
1.LT:Indicates a tire, designated by
the Tire and Rim Association
(T&RA), that is intended for service
on light trucks.
2.Load Range/Load Inflation
Limits:Indicates the tire’s
load-carrying capabilities and its
inflation limits.
3.Maximum Load Dual lb. (kg)
at psi (kPa) cold:Indicates the
maximum load and tire pressure
when the tire is used as a dual; defined as four tires on the rear axle (a
total of six or more tires on the vehicle).
4.Maximum Load Single lb. (kg) at psi (kPa) cold:Indicates the
maximum load and tire pressure when the tire is used as a single;
defined as two tires (total) on the rear axle.
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
156

Information on “T” type tires
“T” type tires have some additional
information beyond those of “P”
type tires; these differences are
described below:
T145/80D16 is an example of a tire
size.
Note:The temporary tire size for
your vehicle may be different from
this example.
1.T:Indicates a type of tire,
designated by the Tire and Rim
Association (T&RA), that is
intended for temporary service on
cars, SUVs, minivans and light
trucks.
2.145:Indicates the nominal width
of the tire in millimeters from
sidewall edge to sidewall edge. In general, the larger the number, the
wider the tire.
3.80:Indicates the aspect ratio which gives the tire’s ratio of height to
width. Numbers of 70 or lower indicate a short sidewall.
4.D:Indicates a “diagonal” type tire.
R:Indicates a “radial” type tire.
5.16:Indicates the wheel or rim diameter in inches. If you change your
wheel size, you will have to purchase new tires to match the new wheel
diameter.
Location of the tire label
You will find a Tire Label containing tire inflation pressure by tire size
and other important information located on the B-Pillar or the edge of
the driver’s door. Refer to the payload description and graphic in the
Vehicle loading — with and without a trailersection.
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
157

TIRE PRESSURE MONITORING SYSTEM (TPMS)
Each tire, including the spare (if
provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on the
vehicle placard or tire inflation pressure label. (If your vehicle has tires
of a different size than the size indicated on the vehicle placard or tire
inflation pressure label, you should determine the proper tire inflation
pressure for those tires.)
As an added safety feature, your vehicle has been equipped with a tire
pressure monitoring system (TPMS) that illuminates a low tire pressure
telltale when one or more of your tires is significantly under-inflated.
Accordingly, when the low tire pressure telltale illuminates, you should
stop and check your tires as soon as possible, and inflate them to the
proper pressure. Driving on a significantly under-inflated tire causes the
tire to overheat and can lead to tire failure. Under-inflation also reduces
fuel efficiency and tire tread life, and may affect the vehicle’s handling
and stopping ability.
Please note that the TPMS is not a substitute for proper tire
maintenance, and it is the driver’s responsibility to maintain correct tire
pressure, even if under-inflation has not reached the level to trigger
illumination of the TPMS low tire pressure telltale.
Your vehicle has also been equipped with a TPMS malfunction indicator
to indicate when the system is not operating properly. The TPMS
malfunction indicator is combined with the low tire pressure telltale.
When the system detects a malfunction, the telltale will flash for
approximately one minute and then remain continuously illuminated.
This sequence will continue upon subsequent vehicle start-ups as long as
the malfunction exists.
When the malfunction indicator is illuminated, the system may not be
able to detect or signal low tire pressure as intended. TPMS malfunctions
may occur for a variety of reasons, including the installation of
replacement or alternate tires or wheels on the vehicle that prevent the
TPMS from functioning properly. Always check the TPMS malfunction
telltale after replacing one or more tires or wheels on your vehicle to
ensure that the replacement or alternate tires and wheels allow the
TPMS to continue to function properly.
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
158

Low Tire Pressure
Warning LightPossible cause Customer Action Required
Solid Warning Light Tire(s)
under-inflated1. Check your tire pressure to
ensure tires are properly
inflated; refer toInflating
your tiresin this chapter.
2. After inflating your tires to
the manufacturer’s
recommended inflation
pressure as shown on the Tire
Label (located on the edge of
driver’s door or the B-Pillar),
the vehicle must be driven for
at least two minutes over
20 mph (32 km/h) before the
light will turn OFF.
Spare tire in use Your temporary spare tire is in
use. (This includes the optional
full-sized matching wheel and
tire). Repair the damaged road
wheel/tire and reinstall it on
the vehicle to restore system
functionality. For a description
on how the system functions,
refer toWhen your temporary
spare tire is installedin this
section.
TPMS
malfunctionIf your tires are properly
inflated and your spare tire is
not in use and the light
remains ON, have the system
inspected by your authorized
dealer.
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
161

Low Tire Pressure
Warning LightPossible cause Customer Action Required
Flashing Warning
LightSpare tire in use Your temporary spare tire is in
use. (This includes the optional
full-sized matching wheel and
tire). Repair the damaged road
wheel and re-mount it on the
vehicle to restore system
functionality. For a description
of how the system functions
under these conditions, refer to
When your temporary spare
tire is installedin this section.
TPMS
malfunctionIf your tires are properly
inflated and your spare tire is
not in use and the TPMS
warning light still flashes, have
the system inspected by your
authorized dealer.
When inflating your tires
When putting air into your tires (such as at a gas station or in your
garage), the Tire Pressure Monitoring System may not respond
immediately to the air added to your tires.
It may take up to two minutes of driving over 20 mph (32 km/h) for the
light to turn OFF after you have filled your tires to the recommended
inflation pressure.
How temperature affects your tire pressure
The Tire Pressure Monitoring System (TPMS) monitors tire pressure in
each pneumatic tire. While driving in a normal manner, a typical
passenger tire inflation pressure may increase approximately 2 to 4 psi
(14 to 28 kPa) from a cold start situation. If the vehicle is stationary
over night with the outside temperature significantly lower than the
daytime temperature, the tire pressure may decrease approximately 3 psi
(20.7 kPa) for a drop of 30° F (16.6°C) in ambient temperature. This
lower pressure value may be detected by the TPMS as being significantly
lower than the recommended inflation pressure and activate the TPMS
warning for low tire pressure. If the low tire pressure warning light is
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
162

ON, visually check each tire to verify that no tire is flat. (If one or more
tires are flat, repair as necessary.) Check air pressure in the road tires. If
any tire is under-inflated, carefully drive the vehicle to the nearest
location where air can be added to the tires. Inflate all the tires to the
recommended inflation pressure.
SNOW TIRES AND CHAINS
Snow tires must be the same size and grade as the tires you
currently have on your vehicle.
The tires on your vehicle have all weather treads to provide traction in
rain and snow. However, in some climates, you may need to use snow
tires and chains. If you need to use chains, it is recommended that steel
wheels (of the same size and specifications) be used, as chains may chip
aluminum wheels.
Follow these guidelines when using snow tires and chains:
•Either cable type chains or SAE class S chains can be used.
•Install chains securely, verifying that the chains do not touch any
wiring, brake lines or fuel lines.
•Drive cautiously. If you hear the chains rub or bang against your
vehicle, stop and re-tighten the chains. If this does not work, remove
the chains to prevent damage to your vehicle.
•If possible, avoid fully loading your vehicle.
•Remove the tire chains when they are no longer needed. Do not use
tire chains on dry roads.
•The suspension insulation and bumpers will help prevent vehicle
damage. Do not remove these components from your vehicle when
using snow tires and chains.
VEHICLE LOADING – WITH AND WITHOUT A TRAILER
This section will guide you in the proper loading of your vehicle and/or
trailer, to keep your loaded vehicle weight within its design rating
capability, with or without a trailer. Properly loading your vehicle will
provide maximum return of vehicle design performance. Before loading
your vehicle, familiarize yourself with the following terms for determining
your vehicle’s weight ratings, with or without a trailer, from the vehicle’s
Tire Label or Safety Compliance Certification Label:
Base Curb Weight– is the weight of the vehicle including a full tank of
fuel and all standard equipment. It does not include passengers, cargo, or
optional equipment.
2008 Grand Marquis(grn)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
163