Engine - In-Car Piston Replacement
S70/V70 (-00) 1999-2000C70 1999-
Section
2
Group
21
No.
0041
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 end cap bolts.
Remove the end cap bolts.
5
Carefully press the pistons upwards. Use special tool 999 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.
Note!
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 as the replaced
pistons 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 upwards.
B = Scraper ring. Bevelling facing downwards.
C = Oil ring. Separated three ways equilaterally.
Ensure that the piston rings can 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 rods correspond.
Install both circlips for the wrist pin. Check that the
circlips are correctly positioned in the piston. The gap
must be vertical.
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
9995746 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 can be moved laterally
The crankshaft must not be rotated before the 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.