Cylinder head removal for New beetle, Golf, Jetta Mk4 A4 body ALH engine
Difficulty 4/5  
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Introduction

Note: Don't be discouraged by the 4/5 rating, you have to remove the timing belt so that makes it a 3/5 minimum.  Add the extra time and possible complications and I decided to make it a 4/5.  It is not technically difficult if you have the proper tools and the job is easier than many cars.  Plan on having the car down for at least a week if this is your first time and you don't have ALL the parts ready.  Because this is a more advanced procedure, it is assumed that you have the Bentley VW service manual, tool sets, and if you are replacing the head, a competent machine shop or new head.  Disclaimer: this article has only pictures and tips to supplement the Bentley service manual.

If you are just changing your head gasket, reuse the old head but I suggest cleaning the intake manifold and intake ports on the head of carbon.  

If your timing belt broke, you will need at a minimum, a new timing belt kit with all new rollers, tensioners, stretch bolts, and preferably a new water pump.  If the timing belt slipped at the water pump or injection pump the car can still run but not very well.  If your timing belt slipped and the engine stalled out, either the injection pump timing slipped and the engine shut off or the valves hit the pistons.  If the valves hit the pistons the car has at least some head damage.  Without professional examination and testing, it is impossible to determine if the head can be re-used with some old components, if the head has to be completely rebuilt, or if the head has to be discarded.  

Do NOT re-use the old head with no professional repair and examination if the timing belt broke and it stalled the engine.  At least take off the camshaft (see 1000q: timing belt removal, part 1) for more details.  Remove the lifters.  They should appear smooth on all surfaces and should spin in their bores.   It is normal for an even disk of fine marks in the top of the lifter where the camshaft makes contact.  Strong marks or scratches can indicate a lifter which is binding.  Cracks or an imprint in the bottom of the lifter is evidence of valve-piston contact which sent the force into the lifter.  Because of this, also beware of buying used heads from someone else - even if it "looks good", it may actually be slightly damaged when you get it.  Even though the VW manual states that the head cannot be repaired, there are people out there who can repair even a gouged and damaged aluminum head to like new specs.  Franko6 on tdiclub is experienced with rebuilding these heads, you can at least contact him for more options.

Parts

Full metric tool set, sockets, wrenches, etc.

new head bolts (x10)
new gasket set - note - check the number of holes punched in the head gasket, it must either match the old gasket or you must measure piston protrusion and order the respective "number of holes" gasket.  An incorrect gasket will change your compression.  See your Bentley manual for more details.  
engine oil and filter
new turbo oil feed line

full timing belt kit, see 1000q: timing belt removal, part 1 for part numbers and detailed procedures
new, rebuilt head, or head repair components (as needed)
hydraulic lifters (as needed)
valves, valve springs, valve keepers, valve guides (as needed)

misc intake and exhaust gaskets
assembly lube

Procedure

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Secure rear wheels with chocks, jack up front of car.

Remove engine under shield, upper engine cover, and engine lower side shields, both driver and passenger side.

Disconnect and remove battery.  Note - this may mess up the immobilizer system, this is an anti theft device that won't let your engine stay running.  You may need to go to the dealer unless you have the proper tools and SKC.  See 1000q: immobilizer FAQ for more details.

Because you will spend some time under the car and the engine bay is probably dirty, take this opportunity to clean the engine bay.  It will help prevent dirt from falling into your face and eyes while working under the car, and make everything easier and cleaner in general.  Always wear eye protection when working on your car, especially when under your car.

To clean the engine bay, remove the battery and cover all electrical switches and the alternator, air filters, etc.  Make sure that you do not get water into the intake tract.  Clean with water, degreaser, etc, as necessary.  Do not get degreaser on the alternator.  Always blow dry all electrical switches and anywhere there may be water.  The TDI engine stands up well to washing because there are gaskets that protect the electrical plugs but it's still best to blow dry spots of standing water.  Let stand until the engine bay is dry before driving.

Remove driver's side plastic cover blocking access to battery tie down (2 phillps screws), and remove battery tie down bracket (top red circle).  Remove battery box (5 bolts, other red circles)

Cover alternator with a plastic bag.

Spray oily areas with degreaser, brush as necessary, and let soak.  Rinse off with water thoroughly.  Make sure to clean the undercarriage and any areas where dirt may be hidden.  Make sure to avoid getting degreaser or chemicals on the alternator.  

Use compressed air to dry, pay attention to electrical connectors and areas of standing water.

While you are under the car, you will be glad that you cleaned all the dirt off.  Under the car, remove white plastic inner cv boot heat shield (2 bolts circled in red).  

Spray PB blaster on turbo exhaust nuts (2 nuts marked by solid yellow arrows, 1 is hidden, marked by dashed yellow arrow) and turbo oil supply union/line (hidden on top, marked by red arrow), let soak, you will loosen them later.  Wear safety goggles at all times.  The turbo oil supply line may get twisted during removal, I suggest having a replacement if you want to minimize car down time.  If it gets twisted at all, do not reuse it.  The best way to avoid twisting it is PB Blaster and counterholding the union while loosening the line.

Spray PB blaster on turbo oil return line (outlined in red) , and turbo support bracket bolt (outlined in yellow), let soak, you will loosen these later.  Wear safety goggles at all times.

If you want to remove intake or exhaust manifold separately, spray everything with PB blaster, and see these below pictures.  The intake and exhaust manifolds can be removed with allen and regular sockets, see the below pictures.  Some of them may be damaged or get stripped, have some EZ-out/bolt-out tools handy in case.

These are thumbnail pictures, click them to see the enlarged pictures with more detail.  See 1000q: intake manifold removal for more details.
    

It can be easier to remove the head with intake and exhaust manifolds attached.

Above the car...

Remove air intake box and it's accordion hose, vacuum ball, vacuum lines, fuel injector lines, glow plug harness, etc.  I suggest a touch of PB blaster on the fuel injector line unions.  If you don't have a flare wrench, you can take a cheap wrench and cut a groove in it to get around the fuel line.  

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Drain coolant, see: 1000 answered questions: how to coolant drain

Drain oil, see 1000 answered questions: how to change your oil

The next steps are identical to timing belt removal part 1.  You have to remove the timing belt or at least remove the belt from the camshaft sprocket.  Refer to: 1000q: timing belt removal: part 1 for more details. 

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Unbolt exhaust downpipe from turbo (10mm x3 bolts), as pictured above.  This is where the PB blaster was needed.  An air wrench will come in very handy here for quick removal of those bolts.  If you didn't clean the engine bay earlier, there will be lots of dirt flying down from the air wrench.  Always wear safety eye goggles.

Remove turbo oil return line and turbo support bracket as pictured before.

Disconnect egr cooler hoses and other coolant hoses.  See 1000q: EGR removal for more details.  Make sure to label them all!

Disconnect all remaining lines to cylinder head - electrical wires, glow plug wires, fuel supply/return lines to the injector pump..

You should now have adequate access to remove the turbo oil supply line.  It goes from the banjo fitting on the oil filter housing, counter clockwise around the engine, then down into the turbo, held with a union.  Use a mirror to examine the line before trying to remove it.  Use a stubby 17mm wrench on the union.  If the oil line gets twisted, it is no longer usable.  If it gets twisted, you can bend it and cut it behind the bend (to prevent metal shavings from entering the oil line), to make it easier to remove.  In the below picture, after I removed the oil supply line, I put a piece of plastic between the unions and tightened it a few turns to hold the plastic in place.  This will also help keep dirt out of the turbo bearings and oil line.  You can also note the labels on the various hoses, lines, etc.

This picture is a thumbnail, click for a larger view.

Here is a picture of a new oil line.  The white plastic banjo bolt holder is the oil filter end, the nut end goes to the turbo.

Remove valve cover (7 allen bolts, marked in yellow below.)

To avoid damaging the camshaft, slightly loosen the camshaft cap bolts in the suggested order of: 1, 5, 3, 2, 4, and in stages before you loosen them completely.  Remove camshaft (10 bolts, marked in blue below).  Make sure to label which bearing cap goes to which spot!  You can use a sharpie permanent marker for this.

Loosen head bolts in sequence and in stages-they are stretch bolts and are not reusable.  Not that the bolt removal order is different from the bolt reinstallation order.  Loosen each bolt slightly first before loosening them all to avoid warping the head.  Loosen and tighten all the head/cam bolts in stages!

Lift off head.  If any coolant or dirt is present, clean immediately.  Cover with a piece of plastic and tape down to keep clean.  If you leave the head exposed for a while, coat the exposed surfaces with some light oil to prevent rusting.

Installation

Clean the exposed surfaces. Make sure that there is no fluid in the head bolt holes - fluid pooling in the bolt holes could hydrolock and crack the block when you torque down the head bolts!  No gasket sealer should be used on the head gasket.  The gasket letters and numbers should face up.  Which head gasket you need is determined by piston protrusion above the block.  The Bentley manual says that you only need to measure piston height if you change the crank, pistons, rods, block, or bearings, etc. but it couldn't hurt to check the piston height anyways since it could change slightly due to high mileage/wear.  If you don't want to do this, just count the punch holes in the gasket and get another one of the same hole count.

When you torque the bolts, tighten them hand tight, then tighten them gradually in the order suggested above by 30 ft lbs each, then 44 ft lbs each, then each 1/4 turn (90^o).  Then turn 1/4 turn again for the final torque (90^o).  Tighten in stages and in order to prevent head warping.  It's suggested to very lightly oil the head bolts and washers by dipping them in oil and letting drip dry to get the proper torques.  See 1000q: torque wrench FAQ for some tips on torque wrench use.

VW uses a special tool to guide the head onto position, you can use old head bolts with the bolt head cut off.  Wood dowels as guides will also work.

If you have to replace only one bolt for whatever reason, you can loosen that one bolt only, it won't warp the head.  If you have to remove more than one bolt, make sure the others are tightened while you work on one bolt at a time only.  If you have to loosen the head bolts or remove the head again, do not reuse the new headgasket, get a new one every time the head comes off.

Install timing belt, see timing belt part 2 - installation,  how to refill engine coolant , and  how to change engine oil as needed.

The rest of installation is the reverse of removal.

Torque specs:
turbo oil return line banjo bolt - 30 ft lbs
turbo oil return line turbo side - 11 ft lbs
turbo/exhaust manifold - exhaust downpipe bolts - 18 ft lbs
exhaust manifold bolts - 18 ft lbs
intake manifold bolts - 18 ft lbs
head bolts - first hand tight each, then 30 ft lbs each in it's required order, then 44 ft lbs each, then each 1/4 turn.  Final tightening, another 1/4 turn.