The timing belt is due to be serviced every 35,000 miles or 5 years. Due to the car being put into service position with the front clip removed, it's recommended to cover a basic list of repairs. While this may seem a bit extensive, it can prevent many issues down the road that could lead to extra repair time. Also a note, the upper/small timing belt rollers are on needle bearings and can loosen and fail early; so if you're in the area for any reason check them out and possibly replace. Here's a list of part numbers for the TB job, and other items that we recommend checking or replacing.
The full parts listing for all items replaced - full timing belt kit, all tensioners, pulleys, bolts, seals etc:
077903137Q Accessory drive belt Qty. 1, 077109479D Tensioner dampener Qty. 1, 077109485F Tensioner pulley Qty. 1, 078109119J Timing belt Qty. 1, 077109244E Timing belt roller Qty. 1, 077109244C Timing belt roller Qty. 2, 077121113D Thermostat Qty. 1, 077121004P Water pump Qty. 1, 078105229D Crankshaft / vibration damper bolt (big bolt!) Qty. 1, N 10135503 Socket head bolt; M8X52 for small relay rollers Qty. 2, N 10194702 Socket head bolt with; hexagon socket head; M10X58 for big relay roller Qty. 1, N 10205604 Hexagon head bolt (combi); M6X32 for tensioner Qty. 3, N 90637102 Hexagon bolt; M10X1X145X45 for camshaft pulleys Qty. 2, 026103085D Shaft oil seal for camshafts Qty. 2, 077115147A Shaft oil seal for crankshaft (front) Qty. 1, N 90827702 Oval hexagon socket head bolt; M6X25 for water pump and t-stat housing Qty. 11, 078109149 Washer for thrust bearing - cam pulley timing washers Qty. 2, G013A8JM1 G13 coolant 1.5ltrs 50/50 mix with distilled water Qty. 2
Valve cover gaskets– Part Number: 077198025A (set of 2) They sell each side separately or you can buy a set; chose the genuine Audi set.
Timing belt– Purchased the whole kit on the RS6.com group buy, or you can buy the whole kit from blauparts.com or similar retailers. The RS6.com kit included the Water Pump and Thermostat; the blauparts.com kit is enhanced to include these as well.
Cam chain tensioner and seals– Purchased the whole kit from blauparts.com. The cam chain tensioner pads can wear out and shatter anywhere from 75k to 150k, so it's recommneded to check and replace these when possible. Logging blocks 70 and 72 with VAGCOM will also give you an indicator of wear on this part. Normal values are around 15; close to 0 or negative and you have a problem.
O2 and EGT sensors– These can be purchased OEM from many retailers. These are known to randomly fail so it never hurts to replace while in there, although they are expensive. The O2's are more recommended, as the EGT's "can" be accessed with the motor in, although a bit difficult."'
Coolant sensor and retainer clip– Part Numbers: 059919501A (coolant sensor); 032121142 (retaining clip)
N75 diverter valves– Part Number: 06A145710P (set of 2) This is mainly for preventive maintenance, given the car is now 12 years old; purchased from ECSTuning.com.
Alternator/Voltage Regulator– Part Number: 077903015RX (alternator); 0031546506 (voltage regulator) Usually the voltage regulator is what can fail due to age; purchase the Voltage Regulator instead and this will be done as part of preventive maintenance; got the part from RMEuropean.com.
G40 camshaft position sensor– Part Number: 058905161B Purchased from RMEuropean.com; Preventive maintenance given the age of the stock part.
Motor mounts– Part Number: Left: 4B3-199-379-J Right: 4B3-199-379-M Purchased at the dealer; preventive maintenance given the age of these items. While these can be spendy, if you're looking to cover everything it's always good to get these done.
Starter assembly– Purchased at the dealer; preventive maintenance given the age of this item;
Oil and filter service– Purchased at the dealer; required given the valve cover gasket service;
Transmission fluid and filter service, rear output shaft seal– Service is recommended every 40,000 miles. Make sure to use the OEM filter and gasket kit. The filter has a fluid pickup tube at the bottom that extends very close to the pan. Out of concern for a dented pan causing lack of fluid pickup, many owners will trim the pickup tube 1/4" to 3/8" maximum. OEM trans fluid is good, but there are several aftermarket brands such as BND, Amsoil, and Shaeffers. The rear driveshaft output seal has been upgraded from the original version, which is known to leak. If the trans is ever out for service look into getting this part upgraded. Make sure to follow the refill instructions closely, and then check fluid level a week later to be sure it's topped off. The Audi transmission manual can be found over on the Extras page on this site.
Turbos– Check for any oil leak on turbos, along with shaft play if you can access them.
EGT Sensor Errors– Before you think about replacing due to a failure code, try re-soldering the lead wire on the PCB.
1) Disconnect the sensor (on the firewall)
2) Pop open the sensor box (putty knife, small screwdriver, whatever)
3) Scoop/scrape the silicone jelly away from the major solder point
4) Flux off all the old solder
5) Melt new solder onto the solder joint
6) Re-coat with silicone jelly (or blue permatex, as I'll be doing)
7) Snap the sensor box back together
8) Reconnect sensor wire
9) Clear codes and watch live data using VAG-COM to see if you're getting good reading from that sensor
If that doesn't fix the issue, replacement doesn't necessarily require an engine drop, but it's a tight fit with the engine in. Will require at least lowering the subframe to be able to get to the sensor lead.
Repairing EGT Sensor wiring– The EGT probes normally do not fail, it is the electronics in the Black (drivers bank 2) and Brown (pass bank 1) boxes. More specifically, the solder joints crack.
If you have original sensors, it is pretty simple to fix; pry off the covers using a small screwdriver and then reflow 5 solder joints with a good soldering iron. Original boxes are filled with a jelly substance, you can push the solder iron through the jelly and reflow the solder pads. If you have newer sensors, you may have issues, the box is filled with black potting. You will have to scrape out this potting to access the solder joints.
When finished you can clear your codes with Vagcom, and run for a few days and recheck the codes. If all is well, use your favorite adheasive to put the covers back on the EGT boxes. You can tell if you have original or newer sensors by looking at the date code on the box covers. If they are newer than your build year you have had the sensors replaced at some point. For Example 08/03 would be original for a USA car. In addition, you may be tempted to buy S4 or A6 2.7TT sensors, these are NOT the same as RS6 sensors. RS6 sensors are a wideband type that read from -40 to 1100 deg C, S4 or A6 2.7TT sensors read from 945 deg C and up.
077919529K (left, Brown, Bank 1)
077919529E (right, Black, Bank 2)
077998124 Kit (both)