Peugeot 405 Haynes (petrol). Manual - part 13

lower end of the specified range, to allow for
wear in use.
30 Where necessary, obtain the required
grades of bearing shell, and repeat the
running clearance checking procedure as
described above.
31 On completion, carefully scrape away all
traces of the Plastigauge material from the
crankshaft and bearing shells. Use your
fingernail, or a wooden or plastic scraper
which is unlikely to score the bearing
surfaces.

XU series engine

32 On early engines, if the later bearing shells
are to be fitted, obtain a set of new upper
bearing shells, and new green or grey (as
applicable) lower bearing shells (see
paragraph 10). On later engines where the
modified bearing shells are already fitted, the
running clearance check can be carried out
using the original bearing shells. However, it is
preferable to use a new set, since the results
obtained will be more conclusive.
33 Clean the backs of the bearing shells, and
the bearing locations in both the cylinder
block/crankcase and the main bearing caps.
34 Press the bearing shells into their
locations, ensuring that the tab on each shell
engages in the notch in the cylinder
block/crankcase or bearing cap. Take care
not to touch any shell’s bearing surface with
your fingers. Note that the upper bearing
shells all have a grooved bearing surface,
whereas the lower shells have a plain bearing
surface  (see illustration). If the original

bearing shells are being used for the check,
ensure that they are refitted in their original
locations.
35 The clearance can be checked in two ways.
36 One method (which will be difficult to
achieve without a range of internal
micrometers or internal/external expanding
calipers) is to refit the main bearing caps to
the cylinder block/crankcase, with bearing
shells in place. With the cap retaining bolts
tightened to the specified torque, measure the
internal diameter of each assembled pair of
bearing shells. If the diameter of each
corresponding crankshaft journal is measured
and then subtracted from the bearing internal
diameter, the result will be the main bearing
running clearance.
37 The second, and more accurate, method
is to use Plastigauge. The method is as
described above in paragraphs 17 to 26,
substituting “main bearing caps” for all
references to the main bearing ladder casting.
38 Note that Peugeot do not specify a main
bearing running clearance for 1905 cc
engines. The figure given in the Specifications
is a guide figure which is typical for this type
of engine. On these engines, therefore, always
refer to your Peugeot dealer for details of the
exact running clearance before condemning
the components concerned.

Final crankshaft refitting

TU aluminium block engines

39 Carefully lift the crankshaft out of the
cylinder block once more.

40 Using a little grease, stick the upper
thrustwashers to each side of the No 2 main
bearing upper location; ensure that the oilway
grooves on each thrustwasher face outwards
(away from the cylinder block) (see
illustration).
41 Place the bearing shells in their locations
as described earlier. If new shells are being
fitted, ensure that all traces of protective
grease are cleaned off using paraffin. Wipe
dry the shells and connecting rods with a lint-
free cloth. Liberally lubricate each bearing
shell in the cylinder block/crankcase with
clean engine oil (see illustration).
42 Refit the Woodruff key, then slide on the
oil pump drive sprocket, and locate the drive
chain on the sprocket (see illustration).
Lower the crankshaft into position so that Nos
2 and 3 cylinder crankpins are at TDC; Nos 1
and 4 cylinder crankpins will be at BDC, ready
for fitting No 1 piston. Check the crankshaft
endfloat as described in Section 13.
43 Thoroughly degrease the mating surfaces
of the cylinder block/crankcase and the main
bearing ladder. Apply a thin bead of suitable
sealant to the cylinder block/crankcase
mating surface of the main bearing ladder
casting, then spread to an even film (see
illustration).
44 Lubricate the lower bearing shells with
clean engine oil, then refit the main bearing
ladder, ensuring that the shells are not
displaced, and that the locating dowels
engage correctly (see illustration).
45 Install the ten 11 mm main bearing ladder

Engine removal and overhaul  2C•19

18.41  Ensure each bearing shell tab

(arrowed) is correctly located, 

and apply clean engine oil

18.44  . . . then lower the main bearing

ladder into position

18.43  Apply a film of suitable sealant to

cylinder block/crankcase mating surface . . .

18.42  Refitting the oil pump drive chain

and sprocket - TU aluminium block engine

18.40  Refitting a crankshaft thrustwasher

- TU series aluminium block engine

18.34  On XU engines, all the lower shells

have a plain bearing surface. Ensure tab

(arrowed) is correctly located in the cap

2C

retaining bolts, and tighten them all by hand
only. Working progressively outwards from
the centre bolts, tighten the ten bolts, by a
turn at a time, to the specified Stage 1 torque
wrench setting. Once all the bolts have been
tightened to the Stage 1 setting, angle-tighten
the bolts through the specified Stage 2 angle
using a socket and extension bar. It is
recommended that an angle-measuring
gauge is used during this stage of the
tightening, to ensure accuracy (see
illustrations). If a gauge is not available, use a
dab of white paint to make alignment marks
between the bolt head and casting prior to
tightening; the marks can then be used to
check that the bolt has been rotated
sufficiently during tightening.
46 Refit all the 6 mm bolts securing the main
bearing ladder to the base of the cylinder
block, and tighten them to the specified
torque. Check that the crankshaft rotates
freely.
47 Refit the piston/connecting rod
assemblies to the crankshaft as described in
Section 18.
48 Ensuring that the drive chain is correctly
located on the sprocket, refit the oil pump and
sump as described in Part A of this Chapter.
49 Fit two new crankshaft oil seals as
described in Part A.
50 Refit the flywheel as described in Part A of
this Chapter.
51 Where removed, refit the cylinder head as
described in Part A. Also refit the crankshaft
sprocket and timing belt as described in 
Part A.

TU series cast-iron block engine

52 Carefully lift the crankshaft out of the
cylinder block once more.
53 Using a little grease, stick the upper
thrustwashers to each side of No 2 main
bearing upper location. Ensure the oilway
grooves on each thrustwasher face outwards
(away from the cylinder block) (see illustration).
54 Place the bearing shells in their locations
as described earlier (see illustration). If new
shells are being fitted, ensure that all traces of
protective grease are cleaned off using
paraffin. Wipe dry the shells and connecting
rods with a lint-free cloth. Liberally lubricate
each bearing shell in the cylinder block/
crankcase and cap with clean engine oil.
55 Lower the crankshaft into position so that
Nos 2 and 3 cylinder crankpins are at TDC;
Nos 1 and 4 cylinder crankpins will be at BDC,
ready for fitting No 1 piston. Check the
crankshaft endfloat, referring to Section 14.
56 Lubricate the lower bearing shells in the
main bearing caps with clean engine oil. Make
sure that the locating lugs on the shells
engage with the corresponding recesses in
the caps.
57 Fit the main bearing caps to their correct
locations, ensuring that they are fitted the
correct way round (the bearing shell lug
recesses in the block and caps must be on
the same side). Insert the bolts loosely.
58 Tighten the main bearing cap bolts to the
specified Stage 1 torque wrench setting.
Once all the bolts have been tightened to the
Stage 1 setting, angle-tighten the bolts
through the specified Stage 2 angle, using a
socket and extension bar. It is recommended

that an angle-measuring gauge is used during
this stage of the tightening, to ensure
accuracy. If a gauge is not available, use a
dab of white paint to make alignment marks
between the bolt head and casting prior to
tightening; the marks can then be used to
check that the bolt has been rotated
sufficiently during tightening.
59 Check that the crankshaft rotates freely.
60 Refit the piston/connecting rod
assemblies to the crankshaft as described in
Section 19.
61 Refit the Woodruff key to the crankshaft
groove, and slide on the oil pump drive
sprocket. Locate the drive chain on the
sprocket.
62 Ensure that the mating surfaces of front
oil seal housing and cylinder block are clean
and dry. Note the correct fitted depth of the
front oil seal then, using a large flat-bladed
screwdriver, lever the seal out of the housing.
63 Apply a smear of suitable sealant to the oil
seal housing mating surface, and make sure
that the locating dowels are in position. Slide
the housing over the end of the crankshaft,
and into position on the cylinder block.
Tighten the housing retaining bolts securely.
64 Repeat the operations in paragraphs 62
and 63, and fit the rear oil seal housing.
65 Fit a new front and rear crankshaft oil seal
as described in Part A of this Chapter.
66 Ensuring that the chain is correctly
located on the drive sprocket, refit the oil
pump and sump as described in Part A of this
Chapter.
67 Refit the flywheel (Part A of this Chapter).
68 Where removed, refit the cylinder head
and install the crankshaft sprocket and timing
belt - see the relevant Sections of Part A.

XU series engines

69 Carry out the operations described above
in paragraphs 52 to 56.
70 Fit main bearing caps Nos 2 to 5 to their
correct locations, ensuring that they are fitted
the correct way round (the bearing shell tab
recesses in the block and caps must be on
the same side). Insert the bolts/nuts,
tightening them only loosely at this stage.
71 Apply a small amount of sealant to No 1
main bearing cap face mating on the cylinder
block, around the sealing strip holes (see
illustration).

2C•20 Engine removal and overhaul

18.45a  Tighten ten 11 mm main bearing

bolts to the stage 1 torque setting . . .

18.53  Fitting a thrustwasher to 

No 2 main bearing upper location

18.71  Applying sealant to the cylinder

block No 1 main bearing cap mating face

18.54  Ensure tab (arrowed) is located in

the cap when fitting the bearing shells

18.45b  . . . then angle-tighten them
through the specified stage 2 angle

72 Locate the tab of each sealing strip over
the pins on the base of No 1 bearing cap, and
press the strips into the bearing cap grooves.
It is now necessary to obtain two thin metal
strips, of 0.25 mm thickness or less, in order
to prevent the strips moving when the cap is
being fitted. Peugeot garages use the tool
shown, which acts as a clamp. Metal strips
(such as old feeler blades) can be used,
provided all burrs which may damage the
sealing strips are first removed (see
illustrations).
73 Where applicable, oil both sides of the
metal strips, and hold them on the sealing
strips. Fit the No 1 main bearing cap, insert
the bolts loosely, then carefully pull out the
metal strips in a horizontal direction, using a
pair of pliers (see illustrations).
74 Tighten all the main bearing cap
bolts/nuts evenly to the specified torque.
Using a sharp knife, trim off the ends of the
No 1 bearing cap sealing strips, so that they
protrude above the cylinder block/crankcase
mating surface by approximately 1 mm (see
illustrations).
75 On 1580 cc, 1761 cc and 1905 cc
engines, refit the centre main bearing side
retaining bolts and sealing washers (one at the
front of the block, and one at the rear) and
tighten them both to the specified torque.
76 Fit a new crankshaft rear oil seal as
described in Part B of this Chapter.
77 Refit the piston/connecting rod
assemblies to the crankshaft as described in
Section 19.

78 Refit the Woodruff key, then slide on the
oil pump drive sprocket and spacer (where
fitted), and locate the drive chain on the
sprocket.
79 Ensure that the mating surfaces of the
front oil seal carrier and cylinder block are
clean and dry. Note the correct fitted depth of
the oil seal then, using a large flat-bladed
screwdriver, lever the old seal out of the
housing.
80 Apply a smear of suitable sealant to the oil
seal carrier mating surface. Ensure that the
locating dowels are in position, then slide the
carrier over the end of the crankshaft and into
position on the cylinder block. Tighten the
carrier retaining bolts to the specified torque.
81 Fit a new crankshaft front oil seal as
described in Part B of this Chapter.
82 Ensuring that the drive chain is correctly
located on the sprocket, refit the oil pump and
sump -refer to Part B or C of this Chapter.
83 Where removed, refit the rear timing cover
and cylinder head as described in Part B.

19 Piston/connecting rod

assembly - refitting and big-
end bearing clearance check

4

Selection of bearing shells

1 On most engines, there are two sizes of
big-end bearing shell produced by Peugeot; a
standard size for use with the standard
crankshaft, and an oversize for use once the
crankshaft journals have been reground.

2 Consult your Peugeot dealer for the latest
information on parts availability. To be safe,
always quote the diameter of the crankshaft
big-end crankpins when ordering bearing
shells.
3 Prior to refitting the piston/connecting rod
assemblies, the big-end bearing running
clearance should be checked as follows.

Big-end bearing 
running clearance check

4 Clean the backs of the bearing shells, and
the bearing locations in both the connecting
rod and bearing cap.
5 Press the bearing shells into their locations,
ensuring that the tab on each shell engages in
the notch in the connecting rod and cap. Take
care not to touch any shell’s bearing surface
with your fingers (see illustration). If the

Engine removal and overhaul  2C•21

18.73a  Fitting No 1 main bearing cap,

using metal strips to retain the side seals

18.74b  . . . then trim the sealing strips, so

that they protrude above the cylinder block

mating surface by approximately 1 mm

18.74a  With all bearing caps correctly

installed, tighten their retaining nuts and

bolts to the specified torque . . .

18.73b  Removing a metal strip from No 1

main bearing cap using a pair of pliers

18.72b  Using the Peugeot special tool to

fit No 1 main bearing cap

18.72a  Fitting a sealing strip to 

No 1 main bearing cap

2C

19.5  Fitting a bearing shell to a connecting

rod - ensure tab (arrowed) engages with

the recess in the connecting rod

original bearing shells are being used for the
check, ensure that they are refitted in their
original locations. The clearance can be
checked in either of two ways.
6 One method is to refit the big-end bearing
cap to the connecting rod, ensuring that they
are fitted the correct way around (see
paragraph 20), with the bearing shells in
place. With the cap retaining nuts correctly
tightened, use an internal micrometer or
vernier caliper to measure the internal
diameter of each assembled pair of bearing
shells. If the diameter of each corresponding
crankshaft journal is measured and then
subtracted from the bearing internal diameter,
the result will be the big-end bearing running
clearance.
7 The second, and more accurate, method is
to use Plastigauge (see Section 18).
8 Ensure that the bearing shells are correctly
fitted. Place a strand of Plastigauge on each
(cleaned) crankpin journal.
9 Refit the (clean) piston/connecting rod
assemblies to the crankshaft, and refit the
big-end bearing caps, using the marks made
or noted on removal to ensure that they are
fitted the correct way around.
10 Tighten the bearing cap nuts as described
below in paragraph 21 or 22 (as applicable).
Take care not to disturb the Plastigauge or
rotate the connecting rod during the
tightening sequence.
11 Dismantle the assemblies without rotating
the connecting rods. Use the scale printed on
the Plastigauge envelope to obtain the big-
end bearing running clearance.
12 If the clearance is significantly different
from that expected, the bearing shells may be
the wrong size (or excessively worn, if the
original shells are being re-used). Make sure
that no dirt or oil was trapped between the
bearing shells and the caps or block when the
clearance was measured. If the Plastigauge
was wider at one end than at the other, the
crankshaft journal may be tapered.
13 Note that Peugeot do not specify a
recommended big-end bearing running
clearance. The figure given in the Specifica-
tions is a guide figure, which is typical for this

type of engine. Before condemning the
components concerned, refer to your Peugeot
dealer or engine reconditioning specialist for
further information on the specified running
clearance. Their advice on the best course of
action to be taken can then also be obtained.
14 On completion, carefully scrape away all
traces of the Plastigauge material from the
crankshaft and bearing shells. Use your
fingernail, or some other object which is
unlikely to score the bearing surfaces.

Final piston/connecting rod
refitting

15 Note that the following procedure
assumes that the cylinder liners (where fitted)
are in position in the cylinder block/crankcase
as described in Section 12, and that the
crankshaft and main bearing ladder/caps are
in place (see Section 18).
16 Ensure that the bearing shells are
correctly fitted as described earlier. If new
shells are being fitted, ensure that all traces of
the protective grease are cleaned off using
paraffin. Wipe dry the shells and connecting
rods with a lint-free cloth.
17 Lubricate the cylinder bores, the pistons,
and piston rings, then lay out each
piston/connecting rod assembly in its
respective position.
18 Start with assembly No 1. Make sure that
the piston rings are still spaced as described
in Section 17, then clamp them in position
with a piston ring compressor.
19 Insert the piston/connecting rod assembly
into the top of cylinder/liner No 1. On petrol
engines, ensure that the arrow on the piston
crown is pointing towards the timing belt end
of the engine and on Diesel engines ensure
that the cloverleaf-shaped cut-out on the
piston crown is towards the front (oil filter
side) of the cylinder block. Using a block of
wood or hammer handle against the piston
crown, tap the assembly into the cylinder/liner
until the piston crown is flush with the top of
the cylinder/liner (see illustration).
20 Ensure that the bearing shell is still
correctly installed. Liberally lubricate the
crankpin and both bearing shells. Taking care
not to mark the cylinder/liner bores, pull the

piston/connecting rod assembly down the
bore and onto the crankpin. Refit the big-end
bearing cap, tightening its retaining nuts
finger-tight at first. Note that the faces with
the identification marks must match (which
means that the bearing shell locating tabs
abut each other). 
21 On TU series engines, tighten the bearing
cap retaining nuts evenly and progressively to
the specified torque setting.
22 On XU series engines, tighten the bearing
cap retaining nuts evenly and progressively to
the stage 1 torque setting. Fully slacken both
nuts, then tighten them to the stage 2 torque
setting. Once both nuts have been tightened
to the stage 2 setting, angle-tighten them
through the specified stage 3 angle, using a
socket and extension bar. It is recommended
that an angle-measuring gauge is used during
this stage of the tightening, to ensure
accuracy (see illustrations). If a gauge is not
available, use a dab of white paint to make
alignment marks between the nut and bearing
cap prior to tightening; the marks can then be
used to check that the nut has been rotated
sufficiently during tightening.
23 On all engines, once the bearing cap
retaining nuts have been correctly tightened,
rotate the crankshaft. Check that it turns
freely; some stiffness is to be expected if new
components have been fitted, but there
should be no signs of binding or tight spots.
24 Refit the remaining three piston/
connecting rod assemblies in the same way.
25 Refit the cylinder head and oil pump as
described in Part A or B of this Chapter (as
applicable).

20 Engine - 

initial start-up after overhaul

1 With the engine refitted in the vehicle,
double-check the engine oil and coolant
levels. Make a final check that everything has
been reconnected, and that there are no tools
or rags left in the engine compartment.
2 Remove the spark plugs. On models with a
distributor, disable the ignition system by

2C•22 Engine removal and overhaul

19.19  Tap the piston into the bore using a

hammer handle

19.22b  . . . then through the angle

specified for stage 3

19.22a  On XU series engines, tighten the

big-end bearing cap nuts to the stage 1

specified torque, then fully slacken them

and tighten them to the stage 2 torque . . .

disconnecting the ignition HT coil lead from
the distributor cap, and earthing it on the
cylinder block. Use a jumper lead or similar
wire to make a good connection. On models
with a static (distributorless) ignition system,
disable the ignition system by disconnecting
the LT wiring connector from the ignition HT
coil, referring to Chapter 5B for information.
3 Turn the engine on the starter until the oil
pressure warning light goes out. Refit the
spark plugs, and reconnect the spark plug
(HT) leads, referring to Chapter 1 for further
information. Reconnect any HT leads or wiring
which was disconnected in paragraph 2.
4 Start the engine, noting that this may take a

little longer than usual, due to the fuel system
components having been disturbed.
5 While the engine is idling, check for fuel,
water and oil leaks. Don’t be alarmed if there
are some odd smells and smoke from parts
getting hot and burning off oil deposits. On
16-valve engines, some valvegear noise may
be heard at first; this should disappear as the
oil circulates fully around the engine, and
normal pressure is restored in the hydraulic
tappet mechanism.
6 Assuming all is well, keep the engine idling
until hot water is felt circulating through the
top hose, then switch off the engine.
7 Check the ignition timing and the idle 

speed settings, then switch the engine off.
8 After a few minutes, recheck the oil and
coolant levels as described in Chapter 1, and
top-up as necessary.
9 If they were tightened as described, there is
no need to re-tighten the cylinder head bolts
once the engine has first run after reassembly.
10 If new pistons, rings or crankshaft
bearings have been fitted, the engine must be
treated as new, and run-in for the first 
500 miles (800 km). Do not operate the engine
at full-throttle, or allow it to labour at low
engine speeds in any gear. It is recommended
that the oil and filter be changed at the end of
this period.

Engine removal and overhaul  2C•23

2C

3

Thermostat

Opening temperatures:

Starts to open:

1360 cc engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

88°C

1580 cc engines:

All except B2A (XU52C) and BDY (XU5M) engines . . . . . . . . . . .

88°C

B2A (XU52C) and BDY (XU5M) engines  . . . . . . . . . . . . . . . . . . .

82°C

1761 cc engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

88°C

1905 cc engines:

All except D2H (XU92C), D5A (XU92C) and 
D6D (XU9J2) engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

88°C

D2H (XU92C), D5A (XU92C) and D6D (XU9J2) engines  . . . . . . .

82°C

1998 cc engines:

RFX (XU10J2C) and RFY (XU10J4) engines  . . . . . . . . . . . . . . . .

89°C

RGZ (XU10J4) engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

88°C

Fully open:

1360 cc engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

100°C

1580 cc engines

All except B2A (XU52C), B3B (XU51C) and 
BDY (XU5M engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

100°C

B2A (XU52C) engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

93°C

B3B (XU51C) engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

102°C

BDY (XU5M) engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

94°C

1761 cc engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

100°C

1905 cc engines:

All except D2H (XU92C), D5A (XU92C) and 
D6D (XU9J2) engines  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

100°C

D2H (XU92C) and D5A (XU92C) engines  . . . . . . . . . . . . . . . . . .

93°C

D6D (XU9J2) engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

94°C

1998 cc engines

RFX (XU10J2C) and RFY (XU10J4) engines  . . . . . . . . . . . . . . . .

101°C

RGZ (XU10J4) engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

100°C

Torque wrench settings

Nm

lbf ft

Coolant pump housing bolts (aluminium block engine):

Smaller bolts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

22

Larger bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65

48

Coolant pump securing bolts (iron block engine) . . . . . . . . . . . . . . . . . .

15

11

Chapter 3
Cooling, heating and ventilation systems

Air conditioning system - general information and precautions  . . . . .10
Air conditioning system components - removal and refitting . . . . . . .11
Antifreeze mixture  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Coolant pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . .7
Coolant level check  . . . . . . . . . . . . . . . . . . . . . . .See “Weekly checks”
Cooling system electrical switches and sensors - 

testing, removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Cooling system - draining  . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Cooling system - filling  . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1

Cooling system - flushing  . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Cooling system hoses - disconnection and renewal  . . . . . . . . . . . . . .2
Electric cooling fan(s) - testing, removal and refitting  . . . . . . . . . . . . .5
General information and precautions  . . . . . . . . . . . . . . . . . . . . . . . . . .1
Heating and ventilation system - general information  . . . . . . . . . . . . .8
Heater/ventilation components - removal and refitting  . . . . . . . . . . . .9
Pollen filter renewal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Radiator - removal, inspection and refitting  . . . . . . . . . . . . . . . . . . . . .3
Thermostat - removal, testing and refitting  . . . . . . . . . . . . . . . . . . . . .4

3•1

Easy, suitable for
novice with little
experience

Fairly easy, suitable
for beginner with
some experience

Fairly difficult,
suitable for competent
DIY mechanic

Difficult, suitable for
experienced  DIY
mechanic

Very difficult,
suitable for expert
DIY or  professional

Degrees of difficulty

Specifications

Contents

1

General information and
precautions

General information

The cooling system is of pressurised type,

comprising a coolant pump driven by the
timing belt, an aluminium crossflow radiator
with integral expansion tank, electric cooling
fan(s), a thermostat, heater matrix, and all
associated hoses and switches.

The system functions as follows. Cold

coolant in the bottom of the radiator passes
through the bottom hose to the coolant pump,
where it is pumped around the cylinder block
and head passages, and through the oil
cooler(s) (where fitted). After cooling the
cylinder bores, combustion surfaces and
valve seats, the coolant reaches the
underside of the thermostat, which is initially
closed. The coolant passes through the
heater, and is returned via the cylinder block
to the coolant pump.

When the engine is cold, the coolant

circulates only through the cylinder block,
cylinder head, and heater. When the coolant
reaches a predetermined temperature, the
thermostat opens, and the coolant passes
through the top hose to the radiator. As the
coolant circulates through the radiator, it is
cooled by the inrush of air when the car is in
forward motion. The airflow is supplemented
by the action of the electric cooling fan(s)
when necessary. Upon reaching the bottom of
the radiator, the coolant has now cooled, and
the cycle is repeated.

When the engine is at normal operating

temperature, the coolant expands, and some
of it is displaced into the expansion tank,
incorporated in the side of the radiator.
Coolant collects in the tank, and is returned to
the radiator when the system cools.

On models with automatic transmission, a

proportion of the coolant is recirculated from
the bottom of the radiator through the
transmission fluid cooler mounted on the
transmission. On models fitted with an engine
oil cooler,  the coolant is also passed through
the oil cooler.

The electric cooling fan(s) mounted in front

of the radiator are controlled by a
thermostatic switch. At a predetermined
coolant temperature, the switch/sensor
actuates the fan.

Precautions

2

Cooling system hoses -
disconnection and renewal

2

Note: Refer to the warnings given in Section 1
of this Chapter before proceeding. Hoses
should only be disconnected once the engine
has cooled sufficiently to avoid scalding.
1 If the checks described in Chapter 1 reveal
a faulty hose, it must be renewed as follows.
2 First drain the cooling system (see 
Chapter 1). If the coolant is not due for
renewal, it may be re-used, providing it is
collected in a clean container.
3 To disconnect a hose, proceed as follows,
according to the type of hose connection.

Conventional hose connections -
general instructions

4 On conventional connections, the clips
used to secure the hoses in position may be
either standard worm-drive clips or
disposable crimped types. The crimped type
of clip is not designed to be re-used and
should be replaced with a worm drive type on
reassembly.
5 To disconnect a hose, use a screwdriver to
slacken or release the clips, then move them
along the hose, clear of the relevant
inlet/outlet. Carefully work the hose free. The
hoses can be removed with relative ease
when new - on an older car, they may have
stuck.
6 If a hose proves to be difficult to remove, try
to release it by rotating its ends before
attempting to free it. Gently prise the end of

the hose with a blunt instrument (such as a
flat-bladed screwdriver), but do not apply too
much force, and take care not to damage the
pipe stubs or hoses. Note in particular that the
radiator inlet stub is fragile; do not use
excessive force when attempting to remove
the hose. If all else fails, cut the hose with a
sharp knife, then slit it so that it can be peeled
off in two pieces. Although this may prove
expensive if the hose is otherwise
undamaged, it is preferable to buying a new
radiator. Check first, however, that a new
hose is readily available.
7 When fitting a hose, first slide the clips onto
the hose, then work the hose into position. If
crimped-type clips were originally fitted, use
standard worm-drive clips when refitting the
hose. If the hose is stiff, use a little soapy
water as a lubricant, or soften the hose by
soaking it in hot water. Do not use oil or
grease, which may attack the rubber.
8 Work the hose into position, checking that it
is correctly routed, then slide each clip back
along the hose until it passes over the flared
end of the relevant inlet/outlet, before
tightening the clip securely.
9 Refill the cooling system with reference to
Chapter 1.
10 Check thoroughly for leaks as soon as
possible after disturbing any part of the
cooling system.

Radiator hose(s) - 
bayonet-type connection

Note: A new O-ring should be used when
reconnecting the hose.

Removal

11 On later models, the radiator hoses are
connected to the radiator using a plastic
bayonet-type connection. To disconnect this
type of connector, proceed as follows.
12 Twist the end of the hose (with the
connector) anti-clockwise until the clips on
the connector are clear of the retaining lugs
on the radiator stub, then pull the end of the
hose from the radiator. Recover the O-ring
from the end of the hose connector (see
illustrations).

Refitting

13 Fit a new O-ring to the hose connector,
then reconnect the hose using a reversal of

3•2 Cooling, heating and ventilation systems

2.12a  Twist the connector until 

the clips (A) are clear of the lugs (B)

Warning: Do not attempt to
remove the expansion tank filler
cap, or to disturb any part of the
cooling system, while the

engine is hot, as there is a high risk of
scalding. If the expansion tank filler cap
must be removed before the engine and
radiator have fully cooled (even though
this is not recommended), the pressure in
the cooling system must first be relieved.

Cover the cap with a thick layer of cloth,
to avoid scalding, and slowly unscrew the
filler cap until a hissing sound is heard.
When the hissing has stopped, indicating
that the pressure has reduced, slowly
unscrew the filler cap until it can be
removed; if more hissing sounds are
heard, wait until they have stopped before
unscrewing the cap completely. At all
times, keep well away from the filler cap
opening, and protect your hands.

Do not allow antifreeze to come into

contact with your skin, or with the painted
surfaces of the vehicle. Rinse off spills
immediately, with plenty of water. Never
leave antifreeze lying around in an open
container, or in a puddle in the driveway
or on the garage floor. Children and pets
are attracted by its sweet smell, but
antifreeze can be fatal if ingested.

If the engine is hot, the electric cooling

fan may start rotating even if the engine is
not running. Be careful to keep your
hands, hair, and any loose clothing well
clear when working in the engine
compartment.

Refer to Section 10 for precautions to

be observed when working on models
equipped with air conditioning.

the removal procedure. Twist the end of the
hose fully clockwise to ensure that the
retaining clips are engaged with the lugs on
the radiator stub.

3

Radiator - removal, inspection
and refitting

3

Removal

1 Disconnect the battery negative lead.
2 Where applicable, disconnect the wiring
from the coolant level sensor, mounted in the
right-hand side of the radiator.
3 Similarly, where applicable disconnect the
wiring from the cooling fan switch, mounted
left-hand side of the radiator.
4 Drain the cooling system as described in
Chapter 1.
5 Where applicable, depress the securing

clip, and release the air inlet tube from the
body front panel, above the radiator (see
illustrations).
6 Where applicable, disconnect the wiring
plug and the vacuum hose from the MAP
sensor, located above the radiator, then
unscrew the two bolts securing the sensor
mounting bracket to the body front panel, and
remove the sensor.
7 Disconnect the upper radiator hose from
the left-hand end of the radiator, with
reference to Section 2.
8 It is now necessary to disconnect the lower
radiator hose(s) from the right-hand side of
the radiator. On some models, particularly
those where conventional hose clips are used,
this is a straightforward task. On other models
(where bayonet connectors are used on a
large-capacity radiator), it is impossible to
gain access to the lower radiator hose
connections without removing the body front
panel assembly, as described in Chapter 11
(see illustration).
9 Once all the radiator hoses have been
disconnected, proceed as follows.
10 If not already done, working at the top of
the radiator, release the two securing clips,
and tilt the radiator back towards the engine
(see illustration).
11 Lift the radiator from the engine
compartment 

(see illustration).

Inspection

12 If the radiator has been removed due to
suspected blockage, reverse-flush it as
described in Chapter 1. Clean dirt and debris
from the radiator fins, using an air line (in
which case, wear eye protection) or a soft

brush. Be careful, as the fins are sharp, and
easily damaged.
13 If necessary, a radiator specialist can
perform a “flow test” on the radiator, to
establish whether an internal blockage exists.
14 A leaking radiator must be referred to a
specialist for permanent repair. Do not
attempt to weld or solder a leaking radiator,
as damage to the plastic components may
result.
15 In an emergency, minor leaks from the
radiator can be cured by using a suitable
radiator sealant, in accordance with its
manufacturer’s instructions, with the radiator
in situ.
16 If the radiator is to be sent for repair or
renewed, remove all hoses, and the cooling
fan switch (where fitted).
17 Inspect the condition of the radiator
mounting rubbers, and renew them if
necessary.

Refitting

18 Refitting is a reversal of removal, bearing
in mind the following points:

a) Ensure that the lower lugs on the radiator

are correctly engaged with the mounting
rubbers in the body panel.

b) Reconnect the hoses with reference to

Section 2, using new O-rings where
applicable.

c) Where applicable, refit the body front

panel assembly, referring to Chapter 11.

d) On completion, refill the cooling system

as described in Chapter 1.

4

Thermostat - removal, testing
and refitting

3

Removal

Note: A new sealing ring may be required on
refitting.
1 Disconnect the battery negative lead.
2 Drain the cooling system as described in
Chapter 1.
3 Where necessary, release any relevant
wiring and hoses from the retaining clips, and
position clear of the thermostat housing to
improve access. On some models, access is

Cooling, heating and ventilation systems  3•3

3.5b  . . . and withdraw the air intake tube

3.11  Lifting out the radiator

3.10  Releasing a radiator 

upper securing clip

3.8  Lower radiator hose connections

viewed with body front panel removed

3.5a  Depress the securing clip . . .

2.12b  Recover the O-ring (arrowed) from

the end of the hose connector

3