| Audi TT 225 Quattro | 1.8T 20v | APX |
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| Prep: | Set aside a day for the job and start early in case you need to make it to the shops and buy any missing tools/sockets etc . Get the car on a level surface and leave ample room around the front and front/right side to make access more comfortable . Read the notes . | Download MS Word printer friendly version - no pictures Click on images below to enlarge : |
| Overview: |
The image on the right shows a removed 20v 1.8T engine with right side clearly visible . Labelled are the : cam sprocket , tensioning roller , tensioning damper , crank sprocket , water pump , ribbed belt tensioning element (Fig 6) attachment and alternator . The timing belt , ribbed belt and pulleys (namely: vane/power steering pump and pulley and vibration damper with pulley) have been removed . For reference , the vibration damper with pulley is installed onto the crank sprocket (see Fig 7) . Other components missing from this image which attach to the engine are : top timing belt cover , center timing belt cover , lower timing belt cover , engine support (Fig 9.3) and engine console (which attaches to the top of the engine support on one side and the chassis on the other . (Fig 9.2 and Fig 9.2b)) . |
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| Step 1: |
After removing the engine and expansion tank covers release the metal pressure pipe . Do this by: (b) unscrewing 2 jubilee/hose clips at each end of the pressure pipe . Optional - To remove the pipe altogether : 2 'clic' hose clips must be undone and the hoses disconnected (indicated with yellow arrow in fig.2) . |
Fig1 |  |
| Step 2: | Chock rear wheels and ensure the handbrake is engaged . Lift the front/right of the car using the Audi jack (or trolley jack with suitable grooved pad) at the designated point and place an axle stand (+ suitable rubber or wooden block) beneath the protective pad or support beam . Gently lower the car onto the axle stand . |
| Step 3: |
Take off the front/right wheel and place it beside the jack . Remove the bottom noise insulation cover (beneath engine) and the wheel arch lining by undoing several Torx 25 screws (Fig 3 - covers removed) . Then remove the plastic shield which covers the lower belt assembly . |
Fig3 |  |
| Step 4: |
This step involves draining the coolant (approx. 5l) : 1. Remove cap from coolant expansion tank 2. Place a bucket underneath the drain tap and attach short hose (Fig 4.1) - the radiator drain screw is located at the bottom right - when facing the car) 3. Turn drain screw on radiator anti-clockwise and pull outwards (Fig 4.2) 4. Disconnect coolant hose at bottom of oil cooler and drain off remaining coolant (access severely restricted) 5. Blow out any remaining coolant by 'applying compressed air' to the expansion tank (Fig 4.3) 6. When all coolant has been drained turn drain screw clockwise and reconnect coolant hose . |
Fig4.1 |  |
| Step 5: |
Detatch coolant expansion tank by undoing 2 bolts and removing 2 hoses and electrical connector (Fig 5.1). Detatch the power assisted steering reservoir by undoing 1 bolt and removing 2 hoses (Fig 5.1) Note : place a rag and small container beneath the reservoir when removing the pipes to avoid spillage of power steering fluid into engine bay . When reinstalling , top up fluid level as necessary . Detatch the activated charcoal filter and move to one side (Fig 5.2). Remove timing belt cover by undoing 2 clips and sliding the cover upwards (Fig 5.1) - the cover will snag on the cam sprocket and is quite tricky to remove Direction of timing belt rotation is clockwise when facing the right side of the engine (Fig 5.3) . | Fig5.1 |  |
| Step 6: |
This step involves removing the ribbed belt and tensioning element : Note : If reusing the old ribbed belt mark the direction of rotation using chalk or a felt marker pen before removal . If the belt rotates in the wrong direction when it is reinstalled , this can cause breakage . Ensure that the belt is properly seated in the pulleys when installing . To slacken ribbed belt for removal attach a suitable open ended spanner onto the tensioning element lobe and turn the tensioning element clockwise . The tensioning element can be locked in position with a suitable punch (4.5 mm diameter, approx. 55 mm long) which fits through a small hole at the base of the lobe . Remove ribbed belt . Remove tensioning element by undoing the bolts . | Fig6 |  |
| Step 7: |
Remove vibration damper by undoing the four allen headed bolts (Hold the centre of the pulley with a 19mm 12 point socket whilst undoing the allen bolts) . Remove center and bottom sections of timing belt guard . | Fig7 |  |
| Step 8: |
Set crankshaft to markings for TDC (top dead centre) of No. 1 cylinder . Do this by turning the central 19mm bolt on crankshaft sprocket in direction of rotation (clockwise) until the TDC marker/notch on the camshaft sprocket is in line with the TDC marker/notch on the valve cover (Fig 8.2) . Mark the TDC position on the belt and valve cover with chalk or felt pen (Fig 8.2). Make another mark on the timing belt which corresponds with the crankshaft sprocket alignment (Fig 8.1) . You can also double check TDC position on the gearbox marker and/or by removing the No. 1 spark plug to expose cylinder 1 . Note : The purpose of making these markings is to have a reference for the replacement belt and to ensure proper reinstallation . | Fig8.1 |
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| Step 9: |
Place trolley jack (+ suitable rubber/wooden block) underneath the engine sump (Fig 9.1) . This is to lift and lower the engine accordingly so that the engine mount bolts can clear the body when being removed . Unbolt engine support from engine console and engine console from body (Fig 9.2) . Engine console is highlighted red (Fig 9.2) . Take out engine console . Note : When replacing , Audi recommend using new 'stretch' bolts (4) that connect from the engine console to the body and to the engine support . Remove bolts for engine support (45Nm) by raising or lowering the engine slightly as necessary with the trolley jack (Caution : do not over-raise/lower) . The engine support cannot be removed yet (Fig 9.3). | Fig9.1 |  |
| Step 10: |
Screw M5x55 stud into timing belt tensioning element . Screw hex nut onto stud using a large washer . Only tension piston of tensioning damper as far as necessary to secure it with a locking pin (e.g. small allen key) . Note : Given the poor access I found that this wasn't possible . Pull out timing belt through space between engine support and engine block . Count the number of teeth between the cam and crank markers on the timing belt (markers made in step 8) . Reproduce these marks on the new belt to ensure the belt is replaced correctly . | Fig10 |  |
| Step 11: |
This step involves removing the Tensioning Roller , Tensioning Damper and Water Pump . Tensioning roller : Remove the allen headed bolt (27Nm) . If re-using the roller , be careful not to lose the washer . Note : at this point I still couldn't slide the engine support out of the way so access was restricted for removing the damper . Tensioning Damper : Remove bolts (15Nm) . Once the damper is out of the way the engine support can be removed . Note : when reassembling , the engine support should be positioned into place before reinstalling the tensioning damper . Water pump : Remove bolts (15Nm) and place a container beneath the water pump to collect coolant . Then pry open water pump from engine with suitable leverage . Note : some force will be required as the pump is wedged in quite securely . A second pair of hands might be useful - especially if you want to avoid using a crowbar (Fig 11.1) and destroying the pump impeller (Fig 11.3). Dry off any coolant spillage (Fig 11.2) . | Fig11.1 |  |
| Step 12: |
The re-installation begins . Note : use thread lock on bolts where appropriate . Bolts with green/blue coloured thread are those which require thread lock . New Water pump : Clean and smooth down sealing surface for O-ring as required and moisten new O-ring with G12 coolant . Tighten bolts to 15Nm . New Tensioning damper : Position engine support into place and install damper . Tighten bolts to 15Nm . Do not release locking pin ! New Tensioning roller : Making sure washer is in place , tighten bolt to 27Nm . |
| Step 13: |
Although unlikely , check that the cam sprocket and crank sprocket are still at TDC and have not been moved . New Timing belt : Direct belt through gap between engine support and engine . Starting from the crank sprocket (bottom) match the belt markings with the corresponding marks made earlier and push belt half-way onto the sprocket . Feed the belt upwards around the water pump and between the tensioning roller and damper and push belt half-way onto the camshaft sprocket making sure that the TDC mark on the belt corresponds with the TDC mark on the valve cover . Important - Make sure that all the belt teeth and sprocket teeth match up . When satisfied with position , push belt fully onto crank/cam shaft sprockets and water pump and between tensioning roller/damper . Note : The belt is taut and may be a little tricky to put on . It may be worth double checking the belt/teeth position one more time before releasing the tensioning damper pin . |
| Step 14: |
Pull out locking pin to release piston of tensioning damper . Turn crankshaft two complete turns in engine direction of rotation to check that the timing is correct and that there is no piston/valve contact . Note : There will be compression pressure as you turn the crank but , if you encounter any sudden resistence then you might be in trouble - in which case you need to re-adjust the timing , or retire and let someone else handle it . Set timing to TDC again and check adjustment . Install lower timing belt guard . Tighten bolts to 10Nm . Install centre timing belt guard . Tighten bolts to 10Nm . Install engine support . Tighten bolts to 45Nm (Fig 9.3) . Install engine console . Tighten engine console -> engine support bolts to 60Nm + 1/4 turn . Tighten engine console -> body bolts to 40Nm + 1/4 turn (Fig 9.2b) . Install top timing belt cover . |
| Step 15: |
Install vibration damper Note : installation position - hole in vibration damper is over projection on crank sprocket . Tighten bolts to 25Nm . Install ribbed belt and tensioning element . Release punch from tensioning element to tension ribbed belt . Install and secure coolant expansion tank , charcoal filter and power assisted steering reservoir . Top up power steering fluid as necessary . Install pressure pipe . |
| Step 16: |
Optional - coolant flush . Pour clean water and radiator flush into coolant expansion tank . Run engine for approx. 2 minutes . Repeat coolant draining process (Step 4) . |
| Step 17: |
This step involves replacing the engine coolant : Top up coolant (approx. 2L (40%) G12 & approx. 3L (60%) Water) to max. mark on expansion tank . This gives frost protection of up to -25 oC . Note : It's a good idea to mix the correct amount of G12 and water into a clean/separate container first before pouring into the expansion tank .
Start engine and run at approx. 1500 RPM for max. 2 minutes and at the same time fill with coolant up to over-flow hole on expansion tank . Install expansion tank cap . Run engine until radiator fan cuts in . Stop engine . Check coolant level and top-up if necessary . When the engine is at normal operating temperature , the coolant level must be on the max. mark , when the engine is cold , between the min. and max. marks . |
| Step 18: |
Replace the arch lining and noise insulation covers . Replace wheel . Tighten bolts to 120Nm . |
| Step 19: | Armed with a bottle of coolant/water mix to top up if necessary , go for a test drive :) |
| Notes: |
The above procedure was carried out on a model year 2000 Audi TT 225 Quattro (European - Left hand drive) , 1.8T 20v , engine code APX at ~80k miles (mostly motorway) . The parts that were replaced still looked in good condition . Audi recommends replacing the timing belt on the TT every 80k miles (~130k km) or every 5 years but there have been a number of reported premature belt failures , so it may be wise to replace it at ~60k miles (~100k km) . Condition of parts inevitably depends on the 'sort' of miles the engine has endured . The condition of the belts also depends on age since they are made of rubber and will deteriorate over time . The job is quite time consuming and the transversely mounted engine means access is very restricted . A lot of the time is spent on removing obstructions out of the way . Take your time and make sure everything is correctly removed/reinstalled first time and stay organised so you don't lose track of what goes where ! It is particularly important to check and double check the timing is correct before starting the engine ! I would strongly advise against doing the timing belt service yourself if you do not have experience with car mechanics . Serious damage to the engine is likely if the engine timing is set incorrectly ! ^ Go back to top ^ |
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| © andrew.p | 30.03.2005 |