Fully dressed engine

2002 Turbo S engine bay

The 1.8 turbocharged dual cam 20-valve engine has many variants — the example illustrated below is similar but not identical to the AWP code Turbo S version.

In the Turbo S, the front of the block faces the right side of the engine bay placing the dipstick in the front of car (although it actually protrudes from the left block side).


In the Turbo S, the front of the engine faces the right side of the engine bay.

A turbocharger
B wastegate actuator
C timing belt
D timing belt drive wheel (exhaust side cam)
E intake cam position sensor (intake side cam)
F hydraulic tensioner
G power steering pump
H water pump
I tensioner
J alternator
K viscous fan clutch (fan has been removed)
L crankshaft pulley
M fuel rail (end only visible)
N coil pack (one of four visible)
P intake manifold
Q throttle
R coolant hose
S oil feed to turbocharger
T coolant feed to turbocharger
U coolant return from turbocharger
V exhaust header
W wastegate vacuum line
Y turbocharger intercooler connection

Top from block left side

A coil pack
B coolant hose
C intake manifold
D throttle body connection (physical cable or electronic system wire)
E fuel rail
F dipstick
G oil fill cap
H wiring harness
J heater core connection
K oil filter cooler line
L oil filter housing
M oil feed to turbocharger
N vacuum hose

Block left lower view

[Wiring harness removed] A viscous fan clutch (fan has been removed)
B water pump
C steering pump drive
D alternator
E throttle body
F intercooler connection
G coolant hose
H oil filter cooler and housing
J oil pan drain plug
L oil filter cooler line
M heater core connection
N dipstick handle
P dipstick mount
Q intake manifold (vacuum line attached)
R crank position sensor (mounted on block)
S knock sensor mount
T oil feed to turbocharger


A wiring harness
B coolant hose
C heater core connection
D intake manifold (with vacuum line back to fuel rail diaphragm)
E oil filter feed to turbocharger
F coolant temperature sensor
G heat shield
H vacuum hose
J oil filter cooler line

Block right side

A coolant hose
B heater core connection
C feed line from oil filer
D coolant return line
E turbocharger
F exhaust header
G turbocharger vent to exhaust
H air outlet to intercooler (connected to throttle body)
J wastegate vacuum line connection
K heat shield
L wiring harness

Valves, cams, and timing

Valve cover

[Wiring harness, accessories, coolant plumping removed] A valve cover with four coil packs removed (chain drive on left)
B oil fill cap
C exhaust header
D turbocharger
E heat shield

Cam shafts

Top dead center on the cam position cup

The 1.8 engine has twenty valves, three intake and two exhaust values per cylinder, with four cylinders configured in-line.

The intake double bearing bridge design firmly holds three cams; the exhaust shaft uses single bearing bridges for its two cams.

The notch on the cam position cup triggers the cam position sensor when the intake cam is at top dead center.

Timing chain

A exhaust cam timing gear
B timing chain cover (cover removed in right image)
C tensioner
D intake cam position cup
E crankshaft pulley
F crankshaft gear
G oil pump intermediate shaft gear

Cam orientation

Square keyways indicate the correct position of the cams at top dead center.

When both cam shafts are correctly positioned for top dead center, the cylinder one exhaust and intake cam point to each other at approximately a 45-degree angle.

Cylinder head, lifters, valves

Head bolt removal tool

The 10 head bolts must be removed with a special tool, a 6-Point, 10mm socket for a 1/2″ drive. Bolts are loosened from the outside in, the opposite of the way these bolts are tightened. Head bolts do not use lock washers; instead they are “stretch” bolts designed for one-time use only.

Bottom of the cylinder head (which is the top of the chamber) shows the exhaust and intake valve tops.

Oil pan and pump