BMW 3 Series Service Manual (E39)
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IRadiator and Cooling System
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I 4 The cooling cassette incorporates cooling coils for various |
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vehicle systems: |
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1. |
Steering fluid cooler |
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2. |
Transmission oil coolel |
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3. |
AIC condenser |
4 In V-8 cars produced after 911998 (M62 TU engine), the engine radiator is divided into an upper chamber (about 80%) and a lower chamber (about 20%). The ATF heat exchanger is coupled to the lower chamber.
On cold engine start-up, the engine coolant is heated more quicltly than the transmission fluid. Heat from engine coolant is usedto warm up the ATF faster, reducing drag in the transmission and improving fuel mileage.
Once the ATF has reached normal operating temperature, the ATF heat exchanger acts as cooling device.The lower 20% of the radiator stays cooler than the upper chamber, so the ATF is cooled more effectively.
4 M62 TU cooling system ducting at radiator:
1. Coolant distribution housing connection
2. Thermostat connection
3. Water cooled alternator connections
4. Transmission fluid heat exchanger connections
Warnings and cautions
O b s e ~ the following warnings and cautions when worlting on the cooling system.
.WARNING-
At normal operating temperature the cooling system is pressurized. Allow the system to cool as long as possible before opening (a minimum of one hour), then release the cap slowly to allow safe release ofpressure.
a Releasing the coolant systempressure lowers the coolant boilingpoint and the coolant may boil suddenly. Use
1 heavy and wear eye and face protection to guard against scalding.
Use extreme care when draining and disposing of engine coolant. Coolant is poisonous and lethal to humans andpets. Pets are attracted to coolant because of its sweet smell and taste. Seek medical attention immediately if coolant is ingested.
C A U T I O G
Avoid adding cold water to the coolant while the engine is hot or overheated.If it is necessary to add coolant to a hol system, do so only with the engine running and coolanl pump turning.
To avoid excess silicate gel precipitation in the cooling system and loss of cooling capacity, use BMW coolant or equivalent low silicate antifreeze.
aIf oil enters the cooling system, the radiator, expansion tank and heating circuit must be flushed with cleaning agent. BMW recommends removal of the radiator and expansion tank to flush.
When worlcing on the cooling system, cover the alternator to protect it against coolant drips.
Prior to disconnecting the battery, read the battery disconnection cautions given in 001 General Warnings and Cautions.
Begin the diagnosis of cooling system problems with a thorough visual inspection. If no visual faults are found, it is recommend that the engine control module (ECM)fault memory be checked for stored diagnostic trouble codes (DTCs)using BMW scan tool DlSplus or equivalent.
Radiator and Cooling System
Check for cloggedlplugged radiator or coolant passages.
Cooling system pressure test
A cooling system pressure tester is used to test for coolant leaks, including internal ones. Common sources of internal coolant leaks are a faulty cylinder head gasket, a craclted cylinder head, or a cracked engine block.
WARNING-
At normal operatingtemperature the cooling system is pressurized. Allow the system to cool before opening. Release the cap slowly to allow safe release ofpressure.
4 With engine cold, install pressure tester (BMW special tools 17 0 002117 0 005 or equivalent) to expansion tank. Pressurize system to specification listed in Table a. Cooling system test pressures.
Pressure should not drop more than 0.1 bar (1.45 psi) for at least two minutes.
.If pressure drops rapidly and there is no sign of external leakage, cylinder head gasket may be faulty. Performcompression and leak-down tests.
Test expansion tank cap using pressure tester with correct adapter (BMW special tool 17 0 007 or equivalent). Replace faulty cap or cap gasket.
Table a. Cooling system test pressures |
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I Component |
l ~ e spressuret |
0021663 |
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Radiator |
11.5 bar (21.75 psi) |
Radiatorcap |
12 bar (29 psi) |
CAUTION-
Exceedingthe specified test pressure could damage the radiator or other svstem com~onents.
170-11
Radiator and Cooling system/
4 Remove drain plug (arrow) at bottom of radiator.
Coolantispoisonous. It is especiallylethalto pets. Clean up spills immediatelyandrinse the area with wate,: Ifcoolant is
-Place a 3-gallon pail beneath the engine block. Remove engine block coolant drain plug and drain coolant.
<M52 TU 1M54 engine: Bloclc drain plug is located on exhaust side of engine block at cylinder 2 (arrow).
M52 engine: Bloclc drain plug is located on exhaust side of engine bloclc between cylinders 3 and 4.
-Reinstall radiator and engine block drain plugs using new sealing washers.
-Before refilling radiator:
Switch ignition to ON. (Do not start engine).
Set temperature controls to full warm.
Set blower control to low.
-Using a coolant mixture of 50% antifreeze and 50% distilled water, fill expansion tank slowly. Continue until coolant
emerges from bleed screw. Cooling system capacity is listed in Table c. Cooling system capacity (6-cylinder models).
NOTE-
Be sure radiator bleedscrew is loose when filling cooling system.
Tap water may cause corrosion of radiator, engine and coolant hoses.
Coolant can be reusedprovided it is clean and less than two years old. Do not reuse coolant when replacing damaged engine parts.
-Bleed cooling system. See Cooling system, bleeding
Table c. Cooling system capacity (6-cylinder models)
Engine |
Capacity |
M52, M52TU, M54 |
10.5 liters (11.1 US qls) |
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IRadiator and Cooling System
Tightening torques |
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Block drain plug to block |
25 Nm (18 ft-ib) |
Radiator drain plug to radiator |
2-3 Nm (18-27 in-lb) |
Coolant, draining and filling (V-8 models)
WARNING-
Allow the cooling system to cool before opening or draining the cooling system.
- Raise front of car and support safely. |
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WARNING- |
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Make sure the car is stable and well supported at all times. |
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Use a professional automotivelift orjack stands designed for |
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the purpose. A floorjack is not adequate support |
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-Remove splash shield from under engine.
Loosen radiator bleed screw at top radiator fining (arrow).
Remove cap from radiator expansion tank. With ignition switch in ON position, set temperature controls to full warm.
Place 5-gallon pail underneath radiator.
4Remove drain plug (arrow) on bottom of radiator and allow coolant to drain.
NOTE-
For radiators without drain plug, remove lower hose to drain radiator.
WARNING-
Coolant is poisonous. It is especially lethal to pets. Clean up spills immediately and rinse the area with water. If coolant is ingested, immediately seek medical attention.
170-13
Radiator and Cooling ~ v s t e m l
<V-8 engine bloclc drain plugs (one shown at arrow) are located on each side of engine block (exhaust manifold removed for photo).
-Place 5-gallon pail underneath engine block coolant drain plugs.
-Remove engine bloclc coolant drain plugs and drain coolant.
-Reinstall radiator and engine block drain plugs using new sealing washers.
-Before refilling radiator:
Switch ignition to ON. (Do not start engine)
-Set temperature controls to full warm. Set blower control to low.
-Using a coolant mixture of 50% antifreeze and 50% distilled water, fill expansion tank slowly. Continue until coolant emerges from bleed screw. Cooling system capacity is listed in Tabled. Cooling system capacity (V-8models).
NOTE-
Be sure radiator bleedscrew is loose when filling cooling system.
Tap water may cause corrosion of radiator, engine and coolant hoses.
Coolant can often be reusedprovided it is clean and less than two years old. Do not reuse coolant when replacing damaged engine parts.
-Bleed cooling system. See Cooling system, bleeding Tabled. Cooling system capacity (V-8 models)
M62, M62 TU |
12.0 liters (12.7 US qts) |
Tighteningtorques |
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Block drain plug |
25 Nm (18 ft-lb) |
Radiator drain plug |
2 - 3 Nm (18 - 27 in-lb) |
Radiator and Cooling System
Cooling system, bleeding
Trapped air in the cooling system can prevent proper coolant circulation and overheating. Wheneverthe coolant is drained and filled, bleed the cooling system to remove trapped air.
4 Loosen bleed screw (arrow) on radiator expansion tank.
-Set temperature controls in passenger compartment to full warm, set blower to low setting and turn ignition to ON position (do not start engine).
CAUTIOIG
On late modelcars with latentheatpump, do not turn ignition to ONposition.
-Slowly add coolanUdistilled water mixture to expansion tank until it spills from bleed screw. When coolant spilling from bleed screws is free of air bubbles, tighten screw and replace cap on expansion tank.
-Run engine until it reaches operating temperature, After engine has cooled, recheck coolant level.
Top up so that coolant level indicator is at MAX.
-If trapped air cannot be bled manually, pressure-bleed system using cooling system pressure tester.
CAUTlON--
Always use genuine BMW coolant or its equivalent to avoid the formation of harmful, cloggingdeposits in the coolingsystem.
Tightening torque
Radiator bleed screw to radiator |
2.5 Nm (22 in-lb) |
Mechanical (viscous clutch) cooling fan, removing and installing
The procedure given here describes the removal of the mechanical fan and fan shroud. It is possible to remove the fan without the shroud.
<Working at top of fan shroud:
Remove expansion tank bleed screw (arrow) and expansion tank locking tabs.
Push top of expansion tank toward engine and lift to free from lower mounts.
-Remove two expansion rivets in upper corners of fan shroud. Unclip expansion tank bleed hose located under shroud.