2010 CADILLAC DTS engine overheat

Driving on Grades
Notice:Do not tow on steep continuous gradesexceeding 6 miles (9.6 km). Extended, higherthan normal engine and transmission temperaturesmay result and damage the vehicle. Frequentstops are very important to allow the engine andtransmission to cool.
Reduce speed and shift to a lower gearbeforestartingdown a long or steep downgrade. If the transmission isnot shifted down, the brakes might have to be used somuch that they would get hot and no longer work well.
On a long uphill grade, shift down and reduce thevehicle’s speed to around 45 mph (70 km/h) to reducethe possibility of the engine and the transmissionoverheating. If the engine does overheat, seeEngineOverheating on page 6-27.
Parking on Hills
{WARNING:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can be
injured, and both the vehicle and the trailer can be
damaged. When possible, always park the rig on a
flat surface.
If parking the rig on a hill:
1. Press the brake pedal, but do not shift into P (Park)yet. Turn the wheels into the curb if facing downhillor into traffic if facing uphill.
2. Have someone place chocks under thetrailer wheels.
3. When the wheel chocks are in place, release thebrake pedal until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parkingbrake and shift the transmission into P (Park).
5. Release the brake pedal.
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Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
•start the engine,
•shift into a gear, and
•release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and storethe chocks.
Maintenance When Trailer Towing
The vehicle needs service more often when pulling atrailer. SeeScheduled Maintenance on page 7-3for moreinformation. Things that are especially important in traileroperation are automatic transmission fluid, engine oil,belts, cooling system and brake system. It is a good ideato inspect these before and during the trip.
Check periodically to see that all hitch nuts and boltsare tight.
Engine Cooling When Trailer Towing
The cooling system may temporarily overheat duringsevere operating conditions. SeeEngine Overheating onpage 6-27.
Changing a Tire When Trailer Towing
If the vehicle gets a flat tire while towing a trailer,be sure to secure the trailer and disconnect it from thevehicle before changing the tire.
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Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-3Accessories and Modifications . . . . . . . . . . . . . . . . . . . . . . . . . .6-3California Proposition 65 Warning . . . . . . . . . . . . . . . . . . . . .6-4California Perchlorate Materials Requirements . . . . .6-4Doing Your Own Service Work . . . . . . . . . . . . . . . . . . . . . . . . .6-4Adding Equipment to the Outsideof the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-5
Fuel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-5Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-5Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-6California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-6Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-6Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-7Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-8Filling a Portable Fuel Container . . . . . . . . . . . . . . . . . . . . .6-10
Checking Things Under the Hood. . . . . . . . . . . . . . . . . . . .6-10Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-11Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . .6-12Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-13Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-16Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-17Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . .6-19Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-22Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-23Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-27
Overheated Engine ProtectionOperating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-29Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-30Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-31Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-32Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-34Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-36
Headlamp Aiming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-40
Bulb Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-43High Intensity Discharge (HID) Lighting . . . . . . . . . . . .6-43
Windshield Wiper Blade Replacement. . . . . . . . . . . . . .6-44
Tires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-46Tire Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-47Tire Terminology and Definitions . . . . . . . . . . . . . . . . . . . . .6-52Inflation - Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-54High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-56Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . . . . . . .6-57Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . .6-58Tire Inspection and Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . .6-62When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . .6-64Buying New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-64Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . .6-66Uniform Tire Quality Grading . . . . . . . . . . . . . . . . . . . . . . . . . .6-67Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . .6-68Wheel Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-68
Section 6 Service and Appearance Care
6-1

How to Check Automatic
Transmission Fluid
Because this operation can be a little difficult, you maychoose to have this done at the dealer/retailer servicedepartment.
If you do it yourself, be sure to follow all the instructionshere or you could get a false reading on the dipstick.
Notice:Too much or too little fluid can damageyour transmission. Too much can mean that someof the fluid could come out and fall on hot engineparts or exhaust system parts, starting a fire.Too little fluid could cause the transmission tooverheat. Be sure to get an accurate reading if youcheck your transmission fluid.
Wait at least 30 minutes before checking thetransmission fluid level if you have been driving:
•When outside temperatures are above 32°C (90°F).
•At high speed for quite a while.
•In heavy traffic — especially in hot weather.
•While pulling a trailer.
To get the right reading, the fluid should be atnormal operating temperature, which is 82°C to 93°C(180°F to 200°F).
Get the vehicle warmed up by driving about 24 km(15 miles) when outside temperatures are above10°C (50°F). If it is colder than 10°C (50°F), you mayhave to drive longer.
Checking the Fluid Level
Prepare the vehicle as follows:
1. Park the vehicle on a level place. Keep the enginerunning.
2. With the parking brake applied, place the shift leverin P (Park).
3. With your foot on the brake pedal, move the shiftlever through each gear range, pausing for aboutthree seconds in each range. Then, positionthe shift lever in P (Park).
4. Let the engine run at idle for three to five minutes.
Then, without shutting off the engine, follow these steps:
1. Locate the transmission fluid cap which is locatednext to the radiator hose and below the engine aircleaner/filter assembly on the driver side of thevehicle. The cap is marked TRANS FLUID.SeeEngine Compartment Overview on page 6-12for more information on location.
2. After removing the engine air cleaner/filter assemblyto reach the transmission fluid cap, turn the capcounterclockwise to remove. Pull out the dipstickand wipe it with a clean rag or paper towel.
6-20

{WARNING:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{WARNING:
Heater and radiator hoses, and other engine parts,
can be very hot. Do not touch them. If you do, you
can be burned.
Do not run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
Notice:Using coolant other than DEX-COOL®cancause premature engine, heater core, or radiatorcorrosion. In addition, the engine coolant couldrequire changing sooner, at 50 000 km (30,000 miles)or 24 months, whichever occurs first. Any repairswould not be covered by the vehicle warranty.Always use DEX-COOL®(silicate-free) coolant inthe vehicle.
Engine Coolant
The cooling system in the vehicle is filled withDEX-COOL®engine coolant. This coolant is designedto remain in the vehicle for five years or 150,000 miles(240 000 km), whichever occurs first.
The following explains the cooling system and how tocheck and add coolant when it is low. If there is aproblem with engine overheating, seeEngineOverheating on page 6-27.
6-23

What to Use
{WARNING:
Adding only plain water to the cooling system can
be dangerous. Plain water, or some other liquid
such as alcohol, can boil before the proper coolant
mixture will. The vehicle’s coolant warning system
is set for the proper coolant mixture. With plain
water or the wrong mixture, the engine could get
too hot but you would not get the overheat
warning. The engine could catch fire and you or
others could be burned. Use a 50/50 mixture of
clean, drinkable water and DEX-COOL®coolant.
Use a 50/50 mixture of clean, drinkable water andDEX-COOL®coolant. If using this mixture, nothing elseneeds to be added. This mixture:
•Gives freezing protection down to!34°F (!37°C),
outside temperature.
•Gives boiling protection up to 265°F (129°C),
engine temperature.
•Protects against rust and corrosion.
•Will not damage aluminum parts.
•Helps keep the proper engine temperature.
Notice:If an improper coolant mixture is used, theengine could overheat and be badly damaged.The repair cost would not be covered by the vehiclewarranty. Too much water in the mixture canfreeze and crack the engine, radiator, heater core,and other parts.
Notice:If extra inhibitors and/or additives are usedin the vehicle’s cooling system, the vehicle couldbe damaged. Use only the proper mixture ofthe engine coolant listed in this manual for thecooling system. SeeRecommended Fluids andLubricants on page 7-8for more information.
6-24

Checking Coolant
The vehicle must be on a level surface when checkingthe coolant level.
Check to see if coolant is visible in the coolant recoverytank. If the coolant inside the coolant recovery tank isboiling, do not do anything else until it cools down.If coolant is visible but the coolant level is not ator above the FULL COLD mark, add a 50/50 mixture ofclean, drinkable water and DEX-COOL®coolant atthe coolant recovery tank, but be sure the coolingsystem is cool before this is done. SeeEngine Coolanton page 6-23for more information.
How to Add Coolant to the Surge Tank
{WARNING:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol and
it will burn if the engine parts are hot enough. Do
not spill coolant on a hot engine.
Notice:This vehicle has a specific coolant fillprocedure. Failure to follow this procedure couldcause the engine to overheat and be severelydamaged.
{WARNING:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
6-25

4. With the coolant surge tank cap off, start the engineand let it run until you can feel the upper radiatorhose getting hot. Watch out for the enginecooling fans.
By this time, the coolant level inside the coolantsurge tank may be lower. If the level is lower, addmore of the proper mixture to the coolant surge tankuntil the level reaches the FULL COLD mark onthe side of the coolant surge tank.
5. Replace the cap. Be sure the cap is hand-tight andfully seated.
Notice:If the pressure cap is not tightly installed,coolant loss and possible engine damage mayoccur. Be sure the cap is properly and tightlysecured.
If coolant is needed, add the proper DEX-COOL®
coolant mixture at the coolant recovery tank.
Engine Overheating
The vehicle has several indicators to warn of engineoverheating.
There is an engine temperature warning light and/orgage on the instrument panel cluster. SeeEngineCoolant Temperature Warning Light on page 4-55andEngine Coolant Temperature Gage on page 4-56.
The vehicle may also display a ENGINE OVERHEATEDIDLE ENGINE message or an ENGINE OVERHEATEDSTOP ENGINE message displayed in the DriverInformation Center (DIC). SeeDIC Warnings andMessages on page 4-67for more information. You willalso hear a chime.
4.6L L37 Engine shown, 4.6L LD8 Engine similar
6-27