Engine - In-Car Piston Replacement
S40/V402000-
Section
2
Group
21
No.
0042
Year
03
Month
04
Pistons! replacing
Background
This method describes how to replace the pistons with the engine in the car.
Special Tools Required
Cylinder liner and piston Piston, replacement
1
Ensure that necessary special tools are available to
carry out this work. Attention to detail and cleanliness
is required to ensure proper repair.
2
Removing the oil sump
Remove the oil sump, see VADIS:
Repair and Installation
Function group 21
Oil sump, replace
3
Removing the cylinder head
All variants:
Remove the cylinder head, see VADIS:
Installation Function
Function group 21
Replacing the cylinder head/gasket.
4
Removing the pistons
Note! On later version engines the connecting rod
and the end cap mating surfaces are aligned by a
dedicated fracture surface. Note the markings on the
connecting rod and the end caps and the direction in
which they are installed, forward, rearward, left, right.
On earlier version engines the connecting rod and end cap
mating surfaces are aligned by serrations. NOT all
connecting rods and end caps may be marked as described
above. If markings are in place then note location as
described above. If NO markings exist stamp or etch the
appropriate cylinder number on each all facing the same
direction.
Turn the crankshaft to bottom dead center to access the
two connecting rod cap bolts.
Remove the end cap bolts.
5
Carefully press the pistons upwards. Use special tool
990 5746.
Ensure that the connecting rod and end cap is marked
as described previously.
Remove the remaining connecting rods and pistons in the
same manner.
Check for vertical abrasions or other damage in the
cylinder liner.
6
Removing the piston from the connecting rod
Note the direction of the arrow on top of the piston
in relationship to the markings on the connecting rod and
end cap. Arrow location may vary from that shown in the
illustration.
Remove the circlips and press out the wrist pin. Clean the
connecting rods and bearing caps before installing new pistons.
Warning!
The circlips can easily spring out. Wear appropriate
eye protection when removing circlips.
Note the piston classification for each cylinder and on
each piston (A). The cylinder classification is etched into
the cylinder block deck in the right rear.
The arrows should always point at the timing belt
transmission.
7
Installing the piston rings
Note!
The new pistons must have the same for each cylinder
Use piston ring pliers.
Turn the piston rings so that the piston ring gaps are
positioned as illustrated.
A = Compression ring. The text on the piston ring
faces upwards.
B = Scraper ring. Bevelling facing downwards.
C = Oil ring. Separated three ways equilaterally.
Caution!
Ensure that the piston ring scan
rotate freely in the piston ring grooves.
Note!
The position of the rings is critical!
Incorrect positioning can result in high oil consumption
8
Assembling the pistons and connecting rods
Note the location of the arrow on top of the piston
and the markings on the connecting rod and end cap.
Install the piston with the arrow in the same
relationship to the markings as when disassembled in
step 6. Assemble the connecting rod and the piston
using the new wrist pin supplied with the piston.
The wrist pin should slide through the connecting rod
small end bearing with light thumb pressure.
Press in the wrist pin by hand.
Check the class of each cylinder/piston diameter.
Check that any markings / numbering of the connecting
reds correspond.
Install both circlips for the wrist pin. Check that
the circlips are correctly positioned in the piston.
The gap must be vertical.
Warning!
The circlips can easily spring out off. Wear
appropriate eye protection when installing
circlips.
Wipe clean the bearing recess in the connecting rod
and cap.
Install new bearing shells.
9
Installing the pistons in the cylinder bores
Using a piston ring compressor install piston and
connecting rod assembly. Follow manufactures recommended
procedures for proper use of ring compressor
Lubricate the cylinder bore, the pistons and the bearing
shells with engine oil.
Turn the crankshaft so the connecting rod is at bottom
dead center for the cylinder piston.
Note!
The arrow on top of the piston should point forward.
Ensure that the classification corresponds.
Carefully press / tap the piston downwards (using a
hammer handle).
When the piston clears the ring compressor and is at head
surface level stop. Put ring compressor aside. Install
holder 999 5746 in the connecting rod.
Pull the connecting rod downwards until it lies against
the crankshaft connecting rod bearing journals.
Remove 999 5746.
10
Tightening the cap for the connecting rod
Install the end cap. Check that markings correspond. On
late types of connecting rods the mating surface between
the cap and the connecting rod are not machined. It is
aligned through a dedicated fracture surface.
Earlier types have serrated surfaces that only align
one way.
Caution!
If the cap is turned the wrong way and tightened,
the structure of the fracture surface will be damaged
and the connecting rod must then be discarded.
Note!
Blow the fracture surfaces of the connecting rod and end
cap dean using compressed air before installing the cap.
Lubricate and install the new screws. Tighten in two stages:
1 20 Nm
2 Angle-tighten 90°
Check that the connecting rod con be moved laterally.
Note!
The crankshaft must not be rotated before the connecting
rod cap has been tightened.
11
Installing the cylinder head
Install the cylinder head, see VADIS:
Repair and Installation
Function group 21
Replacing the cylinder head/gasket.
12
Installing the oil sump
Install the oil sump, see VADIS:
Repair and Installation
Function group 21
Oil sump, replace
13
Topping up
Top up the oil and coolant.
Run the engine to operating temperature.
Check coolant and oil levels.
Check for leakage
WARRANTY STATEMENT:
Claims may be submitted under the New Car Warranty when there is a documented customer complaint, using claim type 01.