Audi 4.2 Timing Belt Replacement – Pt2, Assembly

In the last article, we went over the teardown procedures needed to accomplish a timing belt, water pump, and thermostat removal. This time we will be going over the replacement procedure and the 500,000 different torque values you need to know (not really). Be aware that some of these will be in in./lbs.

First thing you want to do here is get the roller pulleys, eccentric pulley, and hydraulic tensioner bolted down. All of these in the assembly will be torqued to 18 ft. lbs. Do not tighten down the camshaft pulleys or the eccentric pulley yet as there is a procedure for that portion during the tightening of the belt.

Start routing your new timing belt starting at the crank and working counter-clockwise around the assembly. Because this belt has teeth to keep in time, the goal is to keep tight throughout the routing. It will be slack at the end when you cross over the hydraulic tensioner. Once the belt is routed, you can install the crankshaft harmonic balancer pulley (also 18 ft. lbs.).

This is where it gets weird. Double check that both camshafts are at TDC and use the cam position holder (special tool T4005) to hold in place.

Once sure everything is aligned, place a 5MM hex key between the dampener and the pulley assembly. This determines the middle tension that the belt assembly must have during operation…IT’S IMPORTANT! DO NOT PULL THE TENSIONER PIN YET!

You now need to put you attention to the eccentric pulley and using tool T4009 (two prong with 3/8 hole for torque wrench) put 53 in. lbs (6NM) tension on the pulley before tightening it down. The belt should be taught across the assembly.

You can now remove the hex key and pull the pin from the hydraulic assembly to allow the belt to come under proper tension. Side note…allow 6 hours at a minimum to start the car as this hydraulic tensioner takes some time for the oil to stabilize at the new position after being pinned from the assembly line at production.

You now want to tighten down the camshaft sprocket bolts to 41 ft. lbs. They move freely during assembly and belt routing to allow proper tensioning of the belt.

IMPORTANT STEP: Remove the crankshaft pin tool that you installed before removing everything. Place the plug back in the block. You now need to turn the engine over by hand for two revolutions to recheck that your cams and crank are synchronized at TDC. I honestly did mine four revolutions and checked every two just to make sure. If things do not align, you need to re-pin the crank and start at the beginning of realigning everything. DO NOT START THE CAR UNTIL YOU ARE SURE.

From this point, things are easy. Replace the valve covers after replacing the Audi 4.2 valve cover gaskets (known issue point for leaks) and tighten down to prevent anything from getting inside the engine while exposed. Take everything that you took out during the teardown and replace in true Haynes manual fashion (Installation is opposite of removal).

Before you start the engine, check over and ensure everything is connected electrically and no ignition coil, sensor, or vacuum line is left unplugged. The moment of truth is the nerve racking initial cranking of the motor. If anything sounds off, turn the car off immediately.

Everything should be fine if you followed the steps, but sometimes, you may have missed something. As this is a daunting job, take your time and double check all of your work. You do that and you will be fine.


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5 thoughts on “Audi 4.2 Timing Belt Replacement – Pt2, Assembly
  1. Ryan

    Two things I experienced with this job. My cams jumped and would not stay in place with the bar removed and the cams off the taper. I had to adjust one and tighten with the belt in and then bring the other down to get them about level so the bar would fit. This took a few tries.

    Also my book I got from vw called for 20nm and then 1/4 turn. I’ve found this listed as just 18 ft lbs without the quarter turn. I didn’t get the full 1/4 as it felt a little too far by hand.

    Also directions for putting in the 7mm drill bit once the pin was pulled and conflicting pre tensioning after the pin was pulled. The distance between my tensioner and roller was a bit bigger than 5mm. Is this bad. Seems to run fine. But I could always go back in and compress it down a little, as I assume how it is a little bit too tight.

    • The distance is only while adjusting pre tension for the hydraulic tensioner. It should sit between 5mm – 7mm after released and settled. You should be fine where it sits.

      As far as those torque values, these are exact from the latest Audi service program. You go with what you are comfortable with.

      As far as the cams jumping, you get to experience the “pucker” moment. Everything should be ok as long as your marks were aligned after adjusting.

      Best of luck!

      • Ryan

        2 of my manuals I’ve found say 20nm plus 1/4 turn (rs6 and Factory touareg) on the tensioner pulley. One manual for A6 just says 20nm (14.75 ft lbs).

        For the eccentric: 5mm drill bit or Allen wrench in between dampener and tensioner arm, counter clockwise torque at 4nm (I’ve also found 6nm in another manual or at the 1 o’clock position) with the two prong tool and torque bolt to 45nm (33.2).

        Only the idler roller is at 22nm (18 ft lbs) I’ve found everywhere…

        so all three at 18 ft lbs without counter holding isn’t quite right I think.

        The pucker moment is right… both of mine moved and wouldn’t stay TDC while moved back because of the valve spring and no belt to hold it.

        I had to have the special tool to pop the cam off the taper while one side was snugged down somewhat level back on the taper and the belt would counter hold, then the bar with the wings on the other off taper moved level and then snug down… then pop the other one off and slightly level the bar with the wings so the bar would slip in perfectly, then pop the other off the taper while the bar was in place so I could continue to do the other steps before you pull the pin. Without be able to pop the cam off the taper with the bar on the wings, this would have been impossible would have had to pull a valve cover to use a grips or channel locks on a cam to line it up.

        I’m trying to get to the bottom of that tensioner pulley to block torque value as I have three:

        18 ft lbs – yours.
        20nm – some a6 manual.
        20 plus 1/4 – rs6 manual and vw Touareg factory manual from 2011.

        I can’t find the part number for the bolt that goes in the block. It just only seems to come with the tensioner on the vw dealer parts catalog online.

  2. Mark

    “side note…allow 6 hours at a minimum to start the car as this hydraulic tensioner takes some time for the oil to stabilize”

    I have recently done this service and did not do this step, but I am suffering from a belt that has gotten loose over a period of 4 starts. I have asked multiple people who have worked or currently work as an Audi tech and they all have told me the same – never have they even heard of doing this. Could me not waiting 6 hours cause the tensioner to fail ultimately resulting in a loose timing belt? Really scratching my head at this one

    • It could absolutely be because of this fact or a faulty tensioner. A faulty tensioner doesn’t occur very often. Regardless, you’ll have to get in there and repeat the procedure, so you might as well drop a new part in.

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