2010 Lexus GS350 cooling

444
4-3. Do-it-yourself maintenance
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
CAUTION
The engine compartment contains many mechanisms and fluids that may move sud-
denly, become hot, or become electrically energized. To avoid death or serious injury,
observe the following precautions.
■When working on the engine compartment
●Keep hands, clothing, and tools away from the moving fan and engine drive belt.
●Be careful not to touch the engine, radiator, exhaust manifold, etc. right after driv-
ing as they may be hot. Oil and other fluids may also be hot.
●Do not leave anything that may burn easily, such as paper or rags, in the engine
compartment.
●Do not smoke, cause sparks or expose an open flame to fuel or the 12 volt battery.
Fuel and 12 volt battery fumes are flammable.
●Be extremely cautious when working on the 12 volt battery. It contains poisonous
and corrosive sulfuric acid.
■When working near the electric cooling fan or radiator grille
Be sure the “ENGINE START STOP” switch is OFF.
With the “ENGINE START STOP” switch in IGNITION ON mode, the electric
cooling fan may automatically start to run if the air conditioning is on and/or the
coolant temperature is high. (P. 4 5 7 )
■Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc. from getting
in the eyes.
NOTICE
■If you remove the air cleaner filter
Driving with the air cleaner filter removed may cause excessive engine wear due to
dirt in the air. Also a backfire could cause a fire in the engine compartment.

448
4-3. Do-it-yourself maintenance
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
Engine compartment
GS460
Engine oil level dipstick
(P. 4 5 1 )
Engine oil filler cap
(P. 4 5 2 )
Brake fluid reservoir
(P. 4 5 7 )
Fuse box (P. 4 8 4 )
Washer fluid tank (P. 4 6 2 )Engine coolant reservoir
(P. 455)
Electric cooling fans
Condenser (P. 4 5 7 )
Radiator (P. 4 5 7 )
Fuse box (P. 4 8 4 )
12 volt battery (P. 4 5 9 )

449
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
GS350
Engine oil level dipstick
(P. 4 5 1 )
Engine oil filler cap
(P. 4 5 2 )
Brake fluid reservoir
(P. 4 5 7 )
Fuse box (P. 4 8 4 )
Washer fluid tank (P. 4 6 2 )Engine coolant reservoir
(P. 455)
Electric cooling fans
Condenser (P. 4 5 7 )
Radiator (P. 4 5 7 )
Fuse box (P. 4 8 4 )
12 volt battery (P. 4 5 9 )

455
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
Engine coolant
The coolant level is satisfactory if it is between the “FULL” and “LOW”
lines on the reservoir when the engine is cold.
Reservoir cap
“FULL”
“LOW”
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line.
■If the coolant level drops within a short time after replenishing
Visually check the radiator, hoses, reservoir cap, radiator cap, drain cock and water
pump. 
If you cannot find a leak, have your Lexus dealer pressure test the cap and check for
leaks in the cooling system.
■Coolant selection
Only use “Toyota Super Long Life Coolant” or similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.: “Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50%
deionized water. (Enabled: -31F [-35C])
Canada: “Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45%
deionized water. (Enabled: -44F [-42C])
For more details about coolant, contact your Lexus dealer.

456
4-3. Do-it-yourself maintenance
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
CAUTION
■When the engine is hot
Do not remove the radiator and reservoir cap.
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing burns or other injuries.
NOTICE
■When adding the coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of water
and antifreeze must be used to provide proper lubrication, corrosion protection
and cooling. Be sure to read the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.

491
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
FuseAmpereCircuit
18VGRS40VGRS
19MAIN30H-LP R LWR and H-LP L LWR
20STARTER30Starting system
21LH J/B-B30FL DOOR, RL DOOR and RAD
NO.3
22VVT40Electronic engine control system
23EPS80EPS
24ALT180
RH J/B-AM, LH J/B-AM, E/G-AM,
RR JB, HEATER, DEFOG, FAN1,
FAN2, ABS2, ABS MOTOR, 
ABS MAIN1, and ABS MAIN2
25RH J/B-AM80
AM1, OBD, STOP SW, TI & TE, 
PWR OUTLET, FR P/SEAT RH, 
STR LOCK, ECU-IG RH, RH-IG, 
ACC, CIG, SECURITY, 
FR S/HTR RH and AIR SUS
26FA N 380Electric cooling fans
27LH J/B-AM80
S/ROOF, P/SEAT, TV, FL S-HTR,
ECU-IG L, WIP, H-LP LVL, LH-IG,
FUEL OPN, A/C, PANEL, LH-B and
TRK OPN
28ABS230ABS
29DEFFOG50Rear window defogger, noise filter
30CDS40CDS

492
4-3. Do-it-yourself maintenance
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
FuseAmpereCircuit
31FA N 140Electric cooling fans
32HEATER50Air conditioning system
33FA N 240Electric cooling fans
34E/G-AM60H-LP CLN, FR CTRL ALT, A/C
COMP and STB-AM
35RR J/B80
STOP LP R, STOP LP L, RR-B, 
RR TAIL, RR FOG, RR-IG1, PSB, 
and RR S/SHADE

495
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
FuseAmpereCircuit
24RR J/B80
STOP LP R, STOP LP L, RR-B, 
RR TAIL, RR FOG, RR-IG1, PSB, 
and RR S/SHADE
25GLW PLG150Starting system
26RH J/B-AM80
AM1, OBD, STOP SW, TI & TE, 
PWR OUTLET, FR P/SEAT RH, 
STR LOCK, ECU-IG RH, RH-IG, 
ACC, CIG, SECURITY, 
FR S/HTR RH and AIR SUS
27ABS230ABS
28DEFFOG50Rear window defogger, noise filter
29CDS40CDS
30FA N 140Electric cooling fans
31HEATER50Air conditioning system
32GLW PLG250Starting system
33E/G-AM60H-LP CLN, FR CTRL ALT, A/C
COMP and STB-AM
34LH J/B-AM80
S/ROOF, P/SEAT, TV, FL S-HTR,
ECU-IG L, WIP, H-LP LVL, LH-IG,
FUEL OPN, A/C, PANEL, LH-B and
TRK OPN
35FA N 260Electric cooling fans