© Goodheart-Willcox Co., Inc.

(12 Topics)  Cooling system diagnosis  Cooling system problems  Water pump service  Thermostat service  Cooling system hose service  Radiator and pressure cap service

© Goodheart-Willcox Co., Inc.  Fan belt service  Engine fan service  Freeze plug service  Coolant service  Flushing a cooling system  Temperature gauge service

© Goodheart-Willcox Co., Inc.  Gather information:  Talk to the owner or service writer to find out as much as possible about the symptoms Cooling System Diagnosis Chart  A Cooling System Diagnosis Chart in the service manual can be very helpful when problems are difficult to locate and correct.

© Goodheart-Willcox Co., Inc. On-Board Diagnostics trouble code  Cooling-related problems may set a diagnostic trouble code on some systems if temperatures seem out of range.  use a scan tool to analyze the system  MIL lamp may be on  data will indicate engine temperature  even failure to bleed a system of air could cause erratic temperature sensing

© Goodheart-Willcox Co., Inc. Cooling System Functions often monitored by the OBD II system:  Coolant Temperature  Engine oil Temperature  Belt Tension  Other related functions

© Goodheart-Willcox Co., Inc. Visual Inspection of Cooling System  Perform a visual inspection for:  coolant leaks  loose or missing fan belts  low coolant level  water pump noises  plugged radiator fins  coolant in the oil (oil looks milky)  combustion leakage into coolant

© Goodheart-Willcox Co., Inc. Common Problems

© Goodheart-Willcox Co., Inc.  Coolant leaks  Overheating  Overcooling

© Goodheart-Willcox Co., Inc. Coolant Leaks  External leaks  most common  show up as wet, discolored areas on parts  Internal leaks  caused by cracked block, head or blown head gasket

© Goodheart-Willcox Co., Inc. Cooling System Problems a combustion leak test will verify this type of problem A blown head gasket can allow combustion gases to enter the coolant, a combustion leak test will verify this type of problem

© Goodheart-Willcox Co., Inc. Cooling System Problems Mineral deposits in water jackets can prevent proper heat transfer

© Goodheart-Willcox Co., Inc. Cooling System Problems cause a milky white substance to form in the valve covers A cracked part or blown gasket can allow coolant to leak into the engine oil and cause a milky white substance to form in the valve covers

© Goodheart-Willcox Co., Inc.

Pressure Testing a Radiator Cap

© Goodheart-Willcox Co., Inc. Inspecting the Radiator and Pressure Cap  Inspect radiator fins for debris and rot  Make sure the shroud is in place TO AVOID SERIOUS BURNS,NEVER REMOVE A RADIATOR CAP WHEN ENGINE IS HOT!  Perform pressure cap test TO AVOID SERIOUS BURNS, NEVER REMOVE A RADIATOR CAP WHEN ENGINE IS HOT!  measures cap opening pressure  checks sealing washer condition

© Goodheart-Willcox Co., Inc. Cooling System Pressure Tester one of the most commonly used and important cooling system testing devices

© Goodheart-Willcox Co., Inc. Cooling System Pressure Test  Low air pressure is forced into the system  causes coolant to pour or drip from any leak  Install pressure tester on filler neck  Pump the tester to pressurize system  Maximum 14 psi, (or cap rating) to avoid serious damage to cooling system

© Goodheart-Willcox Co., Inc. Combustion Leak Test  Should be performed when indications of a blown head gasket, cracked head, or cracked block are suspected.  Checks for the presence of combustion gases in the coolant  Place combustion leak tester on filler neck  Start engine and squeeze tester bulb, pulling air through test fluid  If combustion gases are present in the radiator, fluid changes color (usually from blue to yellow)

© Goodheart-Willcox Co., Inc. Combustion Leak Test Combustion leakage can make the engine overheat

© Goodheart-Willcox Co., Inc. Combustion Leak Test Leak testing with an exhaust gas analyzer. HC reading indicates leakage

© Goodheart-Willcox Co., Inc. Radiator Removal  Place a catch pan under the cool radiator  Open the petcock to drain system  Disconnect hoses and oil cooler lines  Disconnect wires going to sensors and fan motors  Remove any brackets and radiator

© Goodheart-Willcox Co., Inc. Radiator Removal

© Goodheart-Willcox Co., Inc. Radiator Repair  Most repairs are done by a radiator shop  Radiator shops disassemble, clean, repair, reassemble and test radiators  When installing radiator, make sure the rubber mounts are in place

© Goodheart-Willcox Co., Inc. Causes of Overheating  Low coolant level  Rust or scale accumulation in coolant  Stuck thermostat  Retarded ignition  Loose fan belt  Bad water pump or collapsed lower hose  Missing fan shroud or fan problems  Ice in the coolant

© Goodheart-Willcox Co., Inc. Causes of Overcooling  Stuck thermostat (open)  Locked fan clutch  Shorted fan switch Symptoms of Overcooling  Heater does not get hot  Temperature gage remains cold  Poor fuel economy

© Goodheart-Willcox Co., Inc.  A bad pump may leak, fail to circulate coolant, or produce a grinding sound  Causes:  rust in the cooling system  lack of coolant  overtightened belts

© Goodheart-Willcox Co., Inc. Visual Inspection Pump shaft should not wiggle or leak

© Goodheart-Willcox Co., Inc. Visual Inspection Watch for leakage from bleed holes

© Goodheart-Willcox Co., Inc. Removing a Water Pump  Unbolt brackets and components  air-conditioning compressor  power steering pump  alternator  Remove pump  Scrape off old gasket or sealer material  Do not gouge the sealing surfaces

© Goodheart-Willcox Co., Inc. Installing a Water Pump  Fit pump onto the engine  Start all bolts by hand  Torque all fasteners to specifications  Use sealer where specified  Install the other components

© Goodheart-Willcox Co., Inc. Installing a Water Pump A. Gasket held in place by sealer B. Sealer only

© Goodheart-Willcox Co., Inc. Water Pump This pump uses an O-ring seal instead of sealer or gasket

© Goodheart-Willcox Co., Inc. Installation Tightening water pump bolts

© Goodheart-Willcox Co., Inc. Water Pump Components

© Goodheart-Willcox Co., Inc.  A stuck thermostat can cause engine overheating or overcooling  Stuck open–overcooling  loss of efficiency, power, mileage  high emissions  Stuck closed–overheating  engine damage

© Goodheart-Willcox Co., Inc. Thermostat Testing  Watch the coolant through the opening in the radiator neck  Cold engine, coolant should not flow  Hot engine, coolant should begin to circulate past the opening  Use a digital thermometer to monitor the temperature of the thermostat housing

© Goodheart-Willcox Co., Inc. Thermostat and Housing

© Goodheart-Willcox Co., Inc. Thermostat Replacement

© Goodheart-Willcox Co., Inc. Thermostat and Housing Special O-ring seal should be replaced anytime the thermostat is removed

© Goodheart-Willcox Co., Inc. Bleeding the Cooling System  A bleed valve is sometimes provided  Cars with low hood lines require a bleed screw to empty air pockets  Trapped air can cause overheating or damage from hot spots (buildup of heat)

© Goodheart-Willcox Co., Inc. Bleeding the Cooling System  Fill the system  Start and warm the engine  Crack open the bleed screw until all air is purged from the system  Never remove a cooling system bleed screw or any clamp on a hot, pressurized system

© Goodheart-Willcox Co., Inc. Bleeding the Cooling System

© Goodheart-Willcox Co., Inc. Hoses deteriorate and become soft and mushy or hard and brittle

© Goodheart-Willcox Co., Inc. Common Hose Problems

© Goodheart-Willcox Co., Inc. Hose Replacement A. Loosen clamp, twist and pull hose off B. Clean fitting C. Install new hose and clamp, check for leaks

© Goodheart-Willcox Co., Inc.  A loose fan belt will slip and squeal  may cause overheating  Inspect the condition and tension  Use a belt tension gauge to adjust belts

© Goodheart-Willcox Co., Inc.  A faulty fan can cause overheating, overcooling, vibration and water pump damage  Check for bent blades, cracks or fluid leakage

© Goodheart-Willcox Co., Inc. Testing a Fan Clutch  Start the engine  When cold, fan should slip  When warm, clutch should engage  you should hear the rush of air

© Goodheart-Willcox Co., Inc. Testing an Electric Fan A. Check for power to the fan, engine hot B. Switch open when cold, closed when hot

© Goodheart-Willcox Co., Inc. Leaking freeze plugs cause coolant loss and overheating Occasional replacement may be necessary because of corrosion

© Goodheart-Willcox Co., Inc. Freeze Plug Replacement A. Drive drift through plug, pry out B. Clean and coat hole with sealer, install

© Goodheart-Willcox Co., Inc. Coolant should be checked and changed at regular intervals  Breaks down and becomes acidic  Rust preventative properties are lost

© Goodheart-Willcox Co., Inc. Changing Coolant

© Goodheart-Willcox Co., Inc. Checking Coolant Level Coolant should be even with correct marking on reservoir

© Goodheart-Willcox Co., Inc. Checking Coolant Level Coolant should be 1” below the top of the tank

© Goodheart-Willcox Co., Inc. Testing Coolant Strength  Measures the concentration of antifreeze compared to water  Determines freeze protection  Tools used:  cooling system hydrometer  refractometer

© Goodheart-Willcox Co., Inc. Hydrometer When filled, pointer will float to indicate freeze protection

© Goodheart-Willcox Co., Inc. Refractometer

© Goodheart-Willcox Co., Inc.  Cleans rust and scale from the system  May involve running a cleaning chemical through the system  Methods:  fast flushing  reverse flushing  chemical flushing

© Goodheart-Willcox Co., Inc. Fast Flushing

© Goodheart-Willcox Co., Inc. Reverse Flushing

© Goodheart-Willcox Co., Inc. Chemical Flushing  Used when scale buildup is causing overheating  Chemical cleaner is added to the coolant  Engine is operated for a specific amount of time  System is flushed with water

© Goodheart-Willcox Co., Inc. Gauge problems may include the gauge reading too hot, too cold, or not moving at all

© Goodheart-Willcox Co., Inc. Gauge or Indicator Light Test  Disconnect wire from temperature sending unit  Turn key on, ground wire  If gauge sweeps or light glows as wire is grounded, sender may require replacement  Check service manual before this test

© Goodheart-Willcox Co., Inc. Gauge or Indicator Light Test

© Goodheart-Willcox Co., Inc. Gauge Tester  Used if the gauge is suspected of being faulty or out of calibration  Special device with a variable resistor, replaces the temperature sending unit in the temperature gauge circuit  Set tester to a specified resistance  Gauge should read as specified