Jetta and Passat timing belt part 2 - installation - for 1996, 1997, 1998, 1999 mk3 TDI 1Z and AHU engine
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difficulty 3/5

Introduction

This article shows some tips for timing belt installation for the VW Passat or Jetta mk3 TDI.
Also see: 1000q: timing belt removal for 1Z/AHU TDI , 1000q: water pump removal , 1000q: intermediate shaft seal , and 1000q: injection pump removal or mk4 ALH pump swap.

Procedure

First review 1000q: 1Z/AHU engine timing belt removal  for mk3 jetta and passat TDI.  Also see 1000q: torque wrench FAQ for tips on torque wrench use.

Double check that the camshaft lock and injection pump lock are in place.  Place feeler gauges under the camshaft lock to center it as much as possible.  

Also check that the engine is at TDC.  TDC mark is shown below and after I painted mine.

 

Install the idler pulley (13mm bolt, 18 ft-lbs) and TB tensioner (13mm nut, loosely hand tight only for now).  

Double check that the TB tensioner tab is firmly in it's alignment hole or else the tensioner can fail.  Only loosely hand tighten the TB tensioner nut since you want the center to be able to rotate.  Sorry for the lack of a pic in context, below is a picture of the rear timing belt cover off the engine showing the alignment hole.
 

Slip on the timing belt starting with the crankshaft sprocket and injection pump sprocket.  
The camshaft sprocket should be free to rotate.  Once the teeth are on, slip the camshaft sprocket onto it's tapered end.  Do not tighten the camshaft yet!

Put on the camshaft bolt (19mm) but do not tighten it, just put it on in case the sprocket pops off.

Double check that the engine is at TDC and the camshaft and injection pump lock pin are in.  Now remove the injection pump lock pin.

Use a spanner wrench clockwise to tighten the TB tensioner until the alignment marks are lined up.  It should stay aligned without counterholding the 13mm nut.  Once aligned, tighten the nut to 15 ft-lbs.  Then double check that it's still aligned and that the alignment tab on the back is still in place.  

CAUTION - Although it's possible to tighten the tensioner in a counterclockwise direction, this is wrong, only tighten in a clockwise direction!

Note - the engine should be cold when setting the tensioner.  It automatically adjusts to temperature so don't be surprised if it's off when checking it later on a warm engine.  Remember, if you want to retighten it later, loosen it all the way before retightening it.

You can now tighten the camshaft sprocket bolt, pictured below, to the factory value of 33 ft-lbs but see the caution below!  Remember to counterhold the sprocket when you tighten the bolt!  You can remove the camshaft lock now or later, just make sure to not torque against the lock or else it could crack the camshaft!

CAUTION - Make sure that the tapered conical tip of the camshaft is clean and dry because damage to the threads, tapered camshaft end, or an oiled taper, can change the torque value and result in a spun camshaft sprocket and engine damage!  I personally use a higher torque spec of  35-40 ft-lbs on the camshaft sprocket bolt but never higher than 45.  This is only about a 15% increase in torque over the recommended factory value.  The reason this caution has been added is because there have been reports of multiple spun camshaft sprockets on ALH engines (not mine).  There have not been many reports of this on 1Z/AHU engines but it couldn't hurt.  Regardless of the cause (faulty torque wrench, user error, etc.,), a slightly higher value on this bolt will not damage the camshaft end, sprocket, or the 12mm sprocket bolt, but will add a margin of safety against a spun sprocket.  I believe that this range is a safe balance between spinning the sprocket and any possible damage to the camshaft or sprocket. 

Here is a breakdown of the components so you can decide for yourself:  the bolt, the camshaft threads, the camshaft taper, the sprocket, the belt position.

• The camshaft sprocket bolt is large compared to the low torque value of 33 and will not be damaged by a small increase in torque value.  Later BEW engines use a torque of 74 ft lbs on an identical bolt.  Albeit the engine is different, the bolt is the same.
• The camshaft threads are not brittle enough to be damaged by a 15% increase, my personal suggestion is a limit of 40 although others have tested the camshaft to well over 50 ft-lbs without any damage when using proper tools and pullers.
• The taper is also strong and it is not likely that it will be damaged or deformed by a small increase.  Of course whacking the sprocket with a hammer or improper removal can cause damage so always use a puller or the method in the factory service manual.
• There have not been any reports of damage to the sprocket due to a higher torque.  
• The belt position on the sprocket is not dictated by the sprocket and is unchanged.  

In the end, the torque spec that you want to use is up to you.  A small increase in torque on this bolt can prevent serious damage that has happened to some people.  The increase is not proven to cause any damage so I would rather err on the side of caution.  It's your engine and myturbodiesel is not responsible for any damage as a result of the information found on this website, etc.,...see the disclaimer in the FAQ index for the full TOS. 

Double check for TDC.  If it's fine, remove the camshaft lock if it's still in.

Put the car in neutral gear and rotate the engine twice by hand.  I suggest using the 19mm crankshaft bolt to turn the engine over.  

Do not use the injection pump sprocket to turn over the engine even though it has a lot of teeth engaging the timing belt.  The reason why is because it has to work against the resistance of the valve springs and if you attached the power steering belt and serpentine belt, it can cause the belt to jump the injection pump sprocket.  The camshaft sprocket is a better choice because you aren't working the stress of the valve springs against the belt.  I believe that the crankshaft bolt is still the best choice but do not apply any significant force to it since it's a stretch bolt.  You should feel light resistance as the engine builds compression.  If it seems jammed, double check that the camshaft and injection pump locks are removed and the transmission is in neutral, this could also be a sign that the valves are hitting the pistons.  You can also put the engine back at TDC and double check the injection pump and camshaft locks.  If they are okay, the belt is on correctly.

Put the valve cover and lower timing belt cover back on.  Note: the bentley service manual says the torque for the lower cover bolts/nut is 18 ft-lbs.  I feel this is a typo because this is too much force, especially since it says 10 Nm, which is 7.3 ft-lbs, not 18 ft-lbs.  Reinstall the airbox, accordian hose, and upper timing belt cover.

Again, if you have no bolt at the red arrow pictured above, you could insert a self tapping screw of the correct diameter in there to hold the lower cover on.  I tried a screw but it wasn't secure enough so I used 4 zip ties because it's very difficult to get a bolt in through the back.  I used a zip tie inserted through the timing belt side and then used it to pull 2 zip ties back through the dipstick side.  Putting a cut off zip tie head on each tie held it in place firmly.  1 doesn't work too well, using 2 ties lets them push against each other.  In addition, if they melt and fail, they are plastic and shouldn't damage anything.  Pictured below left is the 2 zip ties with their heads on the other side.  Pictured below right is 2 more zip tie heads securing the first 2 zip tie tails.  The part number for the missing t-head screw is VW # n 900 534 01 but don't bother ordering it unless you can figure out how to insert it from the rear or if the full water pump housing is removed.

Reinstall the crankshaft pulley/harmonic balancer, v-belt and serpentine/alternator belt.

To tension the power steering v-belt, torque the splined tension adjuster to 2.9 ft-lbs for used v-belts, 5.1 ft lbs for new v-belts and then torque it's bolt to 18 ft-lbs.  The v-belt should have about 5mm of deflection in the middle.  The torque for the four harmonic balancer bolts is 15 ft lbs.  Also install the lower engine bay cover.

You will now want to check the timing of the injection pump.  If you don't have a vag-com but the engine starts, you can skip this for now but it's important to at least check this later.  Find someone who has a vag-com if you don't want to buy one.  

To check the timing, warm up the car.  Plug in a vag-com.  In the passat, the plug is to the left of the stereo, in the jetta it is behind the plastic panel above the cigarette lighter spot.  

Enter "basic settings", group 1 or hit enter.  A button should appear "TDI timing".  This brings up a graph.  You want to be above the middle line but below the top line.  This means that you have slightly advanced timing.  This will give easier starting, more power, and better fuel economy.  If it is not, then you may want to adjust the timing.  The vag-com plug location is pictured below.
 

To do adjust timing, remove the upper timing belt cover with the engine off.

Slightly loosen the 3 nuts/bolts that hold the injection pump in front and the 1 bolt that holds it in the rear.  If the bolts are too loose, the pump timing will jump from the top of the graph to the bottom, small adjustments make a big difference.  1 of the front bolts and the rear bolt is circled below in the picture.  The other 2 that are not circled are nuts and accessed (with engine off) through the timing belt side.  The pump was removed in this picture.  The mounting holes on the injection pump are elongated so that you can rotate it slightly.  Twist the entire injection pump on it's mount towards the front or rear and this adjusts timing.  As long as you don't loosen the bolts too much, you can do this with the engine running and see live changes in the timing graph.  Pushing the pump towards the engine advances timing and moves it higher in the timing graph.  Pulling the pump towards the radiator retards timing and moves it lower in the timing graph.  Slightly advanced timing (above the center line) will result in slightly higher EGT, slightly more engine stress, but better fuel economy and power, and easier cold starts.  If I had to choose, slightly advanced timing is preferable to slightly retarded timing although anywhere within the boundaries of the chart is considered acceptable.

Here is a front view, you do not have to remove the sprocket, the sprocket was removed for illustrative purposes only and was from an earlier step.  Obviously your timing belt, rollers, etc. will all be in place.

Once you are satisfied, tighten the injection pump bolts to 18 ft-lbs and reinstall the timing belt cover.  I suggest placing the timing between the middle and upper lines so that it is slightly advanced but still within the limits of the graph.

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Disclaimer:  This page provides only tips to doing the timing belt and is not a substitute for the services of a professional mechanic or the official procedure listed in the factory service manual.  This procedure is rated at 3/5 difficulty, most people with any mechanical experience can successfully do this procedure by following their official factory service manual.  Any or all tips here are superceded by the official factory service manual and by following any or all of these tips, myturbodiesel.com is not responsible for a messed up timing belt job or any damages resulting from it.  See the full terms of use and legal disclaimer here: legal disclaimer,must read!