How to Replace timing belt on Alfa Romeo 156 2.5 24V 2002-2005

Alfa Romeo

Replacement Interval Guide

  • Alfa Romeo recommend:
  • 156/GTV:
  • →12/00:
  • Replacement every 72,000 miles or 5 years under normal conditions.
  • Replacement every 72,000 miles or 3 years under adverse conditions.
  • 01/01→:
  • Check every 36,000 miles.
  • Replacement every 72,000 miles or 5 years under normal conditions.
  • Replacement every 72,000 miles or 3 years under adverse conditions.
  • 166:
  • →12/00:
  • Replacement every 72,000 miles or 5 years.
  • 01/01-08/03:
  • Check every 36,000 miles.
  • Replacement every 72,000 miles or 5 years.
  • 09/03-04/06:
  • Check every 36,000 miles.
  • Replacement every 72,000 miles or 5 years under normal conditions.
  • Replacement every 72,000 miles or 3 years under adverse conditions.
  • 05/06→:
  • Check every 36,000 miles.
  • Replacement every 72,000 miles or 5 years under normal conditions.
  • Replacement every 72,000 miles or 4 years under adverse conditions.
  • The previous use and service history of the vehicle must always be taken into account.

Check For Engine Damage

CAUTION: This engine has been identified as an INTERFERENCE engine in which the possibility of valve-to-piston damage in the event of a timing belt failure is MOST LIKELY to occur. A compression check of all cylinders should be performed before removing the cylinder head(s).

Repair Times – hrs

Remove & install:
GTV (with AC)+0,90

Special Tools

  • Camshaft locking tools (2,5/3,0) – Alfa Romeo No.1825040000.
  • Camshaft locking tools (3,2) – Alfa Romeo No.1870849000.
  • Camshaft sprocket puller – Alfa Romeo No.1860954001.
  • Crankshaft pulley locking tool – Alfa Romeo No.1870646000.
  • Dial gauge and adaptor – Alfa Romeo No.1825013000.
  • Flywheel locking tool (GTV 1997) – Alfa Romeo No.1820088000.
  • Sprocket holding tool – Alfa Romeo No.1822146000.
  • Timing belt tensioning tool – Alfa Romeo No.1860950000.

Special Precautions

  • Disconnect battery earth lead.
  • DO NOT turn crankshaft or camshaft when timing belt removed.
  • Remove spark plugs to ease turning engine.
  • Turn engine in normal direction of rotation (unless otherwise stated).
  • DO NOT turn engine via camshaft or other sprockets.
  • Observe all tightening torques.
  • Removal

    1. Raise and support front of vehicle.
    2. Remove:
        • 166/GTV: Engine upper cover(s).
        • RH front wheel.
        • Inner wing panel.
    3. Turn auxiliary drive belt tensioner anti-clockwise [1] .
    4. Lock auxiliary drive belt tensioner. Use suitable pin.
    5. Remove:
        • Auxiliary drive belt.
        • Auxiliary drive belt tensioner.
        • GTV: Auxiliary drive belt guide pulley.
        • 166: PAS reservoir and bracket.
        • Inlet manifold [2] .
        • Ignition coils cover [3] .
        • Ignition coils [4] .
        • Cylinder head covers [5] .
        • Timing belt upper cover [6] .
        • Timing belt lower covers [7] .
        • Spark plug – cylinder No.1.
        • GTV 1997: Exhaust downpipe.
        • GTV 1997: Flywheel cover.
    6. Except GTV 1997: Fit crankshaft pulley locking tool. Tool No.1870646000.
    7. GTV 1997: Fit flywheel locking tool. Tool No.1820088000.
    8. Slacken crankshaft pulley nut [20] .
    9. Remove:
        • Locking tool. Tool No.1870646000 or 1820088000.
        • Crankshaft pulley [8] .
    10. Fit dial gauge and adaptor to No.1 cylinder [9] . Tool No.1825013000.
    11. Turn crankshaft clockwise until No.1 cylinder at TDC of compression stroke. Use dial gauge.
    12. Slacken timing belt tensioner bolts [10] .
    13. Remove timing belt.


    1. Ensure No.1 cylinder at TDC of compression stroke. Use dial gauge [9] .
    2. Remove four camshaft bearing caps [11] .NOTE: Mark bearing caps before removal for identification.
    3. Fit locking tools in place of bearing caps [11] .
        • 2,5/3,0: Tool No.1825040000.
        • 3,2: Tool No.1870849000.

      NOTE: Ensure locking tools aligned with respective cam profiles to prevent damage.

    4. GTV: Remove engine steady bar and bracket.
    5. Hold camshaft sprockets. Use tool No.1822146000 [12] .
    6. Slacken bolt of each camshaft sprocket [13] [14] .
    7. Ensure camshaft sprockets can turn freely without tilting.
    8. If not: Use puller. Tool No.1860954001.
    9. Fit timing belt in anti-clockwise direction, starting at crankshaft sprocket.
    10. GTV 1997:
        • Support engine.
        • Remove bolts securing rear gearbox mounting to crossmember.
        • Lower rear of engine slightly.
    11. Remove:
        • Lower alternator bolt.
        • Water pump bolt.
    12. Fit tensioning tool [15] . Tool No.1860950000.NOTE: Ensure tensioning tool correctly located on tensioner lever [16] .
    13. Turn tensioning tool nut [17] until notch on lever positioned below fixed mark [18] .
    14. Hold camshaft sprockets. Use tool No.1822146000 [12] .
    15. Tighten bolt of each camshaft sprocket [13] [14] . Tightening torque: 68-84 Nm.
    16. Remove:
        • Camshaft locking tools [11] .
        • Dial gauge and adaptor [9] .
    17. Lubricate and fit bearing caps in correct locations.
    18. Tighten bearing cap bolts to 18-20 Nm.
    19. Turn crankshaft two turns clockwise.
    20. Check tensioner marks aligned [19] .
    21. If not: Turn tensioning tool nut [17] until marks aligned.
    22. Tighten tensioner bolts [10] . Tightening torque: 17-21 Nm.
    23. Remove tensioning tool [15] .
    24. Install components in reverse order of removal.
    25. Tighten crankshaft pulley nut [20] . Tightening torque: 200-247 Nm.
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Bent Valves
Timing Tools?
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Bent Valves

What happens when your chain or belt breaks. 

The timing of course becomes way off. Your crankshaft will always spin making the pistons move up and down. However the valves will remain in the position they were in when the belt or chain stopped working. 

Half of the valves will be stuck open and in the way of the pistons. Not all engines, but most. The piston out of valve time will smash right into the open valve and bend the, The only way to fix that is to remove the head and place those valves. 

If you think your valves might have been damaged.

Remove all the spark plugs, valve covers. With both valves in the closed position insert a compression tester hose in place of the spark plug and inject air into the hose and see if the cylinder can hold air. If both valve are closed and air can not be held, chances are you have bent valves.   


Timing Tools?

Do you need special tools to time your engine? Not always, on all my post I'll indicate that in each post if you do or not. 

But what are these special tools? Normally you would just line up some marks on the cam and crank gears and simply be done with it. However when these tools are needed they are very very important. 

The last one I did was a 2013 Range Rover 2.0 Turbo with dual cams. There were not timing marks at all. 

There is a small threaded plug on the back of the engine that I removed to insert a special threaded pin that would rest up against the weight of the crankshaft to prevent for DTC of the #1 piston. No further clockwise rotation would be possible. At that point I installed the supplied crankshaft lock by removing the starter. 

Then you line up the back of both camshafts to a notch in each camshafts to each other that a flat tool connects to each cam so they are in line with each other. But first you would make sure both intake and exhaust valves are closed DTC of the cams. 

And the last tool was to lineup the crankshaft position sensor. 



The most important thing in any major engine work is to rotate the engine by hand at least two complete rotations. And do it easy and slow and with the spark plugs removed. 

Why remove the spark plugs? you may ask. Simple, with the plugs in place you'll be creating compression, making the engine harder to turn by hand and perhaps giving you the misconception of valves hitting the pistons or is it compression.  

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