Honda Bmw 5 Service Manual

170-5 
Radiator and Cooling System 
Fan switch  calibration (M52, M62 engine) 
coniprairoi OUt rlgnal 
Auto. ciimilte ~ontioi inpuls via CAN bus 
Electric fan activation: 
Low  speed 
91°C (196°F) 
High  speed 104 C (21 9 F) 
< In models  manufactured after  911998 (M52 TU engine,  M54 
engine. 
M62 TU engine),  the electric cooling  fan is controlled 
by  the  engine  control  module  (ECM) via  the output final 
stage. 
The  output final  stage is mounted on the  fan housing, next  to 
the  fan motor....

.. - - 
I Radiator and Cooling System 
I I 4 The cooling cassette incorporates cooling coils  for various 
vehicle systems: 
1. Steering fluid cooler 
2.  Transmission  oil 
coolel 
3. AIC condenser 
4 In V-8 cars produced  after 911998 (M62 TU engine), the en- 
gine  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...

Warnings and cautions 
Obse~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 system  pressure lowers the cool- 
ant boilingpoint  and the coolant may boil suddenly.  Use 
1 heavy  and wear  eye and  face...

170-8 
I Radiator and Cooling System 
Common cooling system faults can be  grouped into one  of 4 
categories: 
Cooling system 
lealts 
Poor  coolant  circulation 
Radiator  cooling fan faults 
Electrical/electronic faults 
Cooling  system inspection 
- Check that coolant  pump drive belt tensioner  is  functioning 
properly and  that belt tension  is correct.  Belt tensioner  sys- 
tems  for the  different  models are shown  in 
020 Maintenance. 
- Check condition  of coolant  pump drive  belt. 
-...

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 cyl- 
inder  head,  or a cracked engine block. 
WARNING- 
At  normal  operating  temperature  the cooling system is pres- 
surized.  Allow the system  to cool  before  opening.  Release 
the  cap...

170-1 0 
I Radiator and Cooling System 
Combustion chamber leak test 
- If you suspect  that combustion  chamber  pressure  is leaking 
into  the cooling  system  past the cylinder  head gasket, use  an 
exhaust  gas analyzer  to test  the vapors  rising from  the cool- 
ant  at the  expansion  tank. 
CAUTIO& 
Use an extension tube above the reservoir neclc to main- 
tain  distance between  the top  of the coolant  and the gas 
analyzer 
nozzle. The  gas  analyzer  is easily damaged  if it  is 
allowed...

170-1 1 
Radiator and Cooling system/ 
4 Remove drain plug  (arrow) at bottom  of radiator. 
Coolant  is poisonous.  It is  especially  lethal to pets. Clean  up 
spills immediately  and rinse  the area  with 
wate,: If coolant  is 
- Place a 3-gallon  pail beneath the  engine block.  Remove en- 
gine block  coolant drain plug and drain coolant. 
< M52 TU 1 M54  engine:  Bloclc drain plug is located  on exhaust 
side  of engine  block at cylinder 
2 (arrow). 
M52  engine: 
Bloclc drain plug  is located...

170-1 2 
I Radiator and Cooling System 
Tightening torques 
Block  drain plug to 
block 25 Nm (1 8 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. 
I WARNING- 1 
Make sure the car  is stable  and well supported  at all  times. 
Use a professional automotive lift 
orjack stands designed  for 
I the...

170-1 3 
Radiator and Cooling ~vsteml 
< V-8 engine bloclc drain plugs (one shown at  arrow) are locat- 
ed 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...

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 posi- 
tion  (do not start engine). 
CAUTIOIG 
On late  model  cars with...