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Replacing Your Audi A4 Head Gasket
 
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Pelican Technical Article:

Replacing Your Audi A4 Head Gasket

Steve Vernon

Time:

12 hours12 hrs

Tab:

$25 to $500

Talent:

*****

Tools:

All of them

Applicable Models:

Audi A4 (2002-05)
Audi A4 Cabriolet (2003-06)

Parts Required:

New head gasket set

Hot Tip:

Have a friend or engine hoist to help

Performance Gain:

Working engine

Complementary Modification:

Radiator flush

There are several signs that you are in need of a new head gasket. The most common amongst them is the mixing of your oil and coolant. If you have had a water pump or thermostat fail, and your car overheated, there is a very good chance you are going to be looking at performing this job, as the extreme temperatures associated with an over heated engine can damage both the head and its gasket.

Replacing your head gasket might be the biggest job you will attempt on your car short of rebuilding the entire engine. It is not a quick or easy job, but can be done by a DIY mechanic if you take your time, have the right tools and follow the instructions. This job can take a few days for a novice, so make sure you have the car in a secure and weather safe area before you start. You are going to be opening up the engine and may even be sending the head out for repairs, so you don't want to be working outside when it starts to rain.

I can not stress this enough: get a digital camera and take lots of pictures before and during this job. Be sure to document the wire and vacuum routing plus anything you feel unsure of. This will be a big help when it comes time to put everything back together.

If the head gasket has failed and you are going to all the trouble to replace it you really should have the head sent out to have it cleaned and inspected. Aluminum heads have a tendency to warp. If your head has warped, putting a new gasket on a warped head will not solve any problems and just cause the head gasket to fail again.

There are several steps that need to be performed on other parts of the car before you begin removing the cylinder head. We have covered all of these in separate articles so I am not going to include them here. This will be a long enough project as it is. Please refer to all the prep work articles contained here on Pelican Parts.

Begin by safely raising and supporting your vehicle. Consult the Pelican article on this procedure, should you need more information.

Begin by removing the panel for the battery and disconnecting the ground terminal (red arrow).
Figure 1

Begin by removing the panel for the battery and disconnecting the ground terminal (red arrow). Make sure the cable cannot accidentally come in contact with the post while you are working.

You are going to need to drain the coolant and since you are draining the coolant it is a very good idea to remove the coolant reservoir (red arrow); this will free up lots of much needed room for working.
Figure 2

You are going to need to drain the coolant and since you are draining the coolant it is a very good idea to remove the coolant reservoir (red arrow); this will free up lots of much needed room for working. You will also need to move the lock carrier (yellow arrow) to the service position. Please see our articles on coolant reservoir replacement and moving the lock carrier to the service position for additional assistance.

Next, remove the accessory belt (yellow arrow) and belt tensioner (red arrow).
Figure 3

Next, remove the accessory belt (yellow arrow) and belt tensioner (red arrow). Please see our article on accessory belt and tensioner removal for further information.

Remove both timing covers.
Figure 4

Remove both timing covers. Set both the crank and head sprockets at Top Dead Center (TDC, red arrows) and release the tension on the timing belt tensioner (yellow arrow) and remove the timing belt. Please see our articles on timing belt replacement for additional information.

Remove the fuel injectors (red arrow) along with the throttle body hose (yellow arrow).
Figure 5

Remove the fuel injectors (red arrow) along with the throttle body hose (yellow arrow). Please see our articles on throttle body and fuel injector replacement for additional assistance.

On the front of the engine, remove the wiring harness for the camshaft positioning sensor by unclipping the wire (red arrow) and slipping the connection off (yellow arrow).
Figure 6

On the front of the engine, remove the wiring harness for the camshaft positioning sensor by unclipping the wire (red arrow) and slipping the connection off (yellow arrow).

Remove the vacuum hose from the intake manifold (red arrow).
Figure 7

Remove the vacuum hose from the intake manifold (red arrow).

Using a set of pliers, remove the larger vacuum line from the rear of the intake manifold (red arrow).
Figure 8

Using a set of pliers, remove the larger vacuum line from the rear of the intake manifold (red arrow).

Remove the air intake sensor by sliding the metal retaining clip up and then pulling the connector off (red arrow).
Figure 9

Remove the air intake sensor by sliding the metal retaining clip up and then pulling the connector off (red arrow).

Loosen the clamp and then remove the vacuum line connected just below the air intake sensor (red arrow).
Figure 10

Loosen the clamp and then remove the vacuum line connected just below the air intake sensor (red arrow).

Remove the connector for the electronic throttle body by releasing the clip with a small screwdriver (red arrow) and pulling the connection straight off.
Figure 11

Remove the connector for the electronic throttle body by releasing the clip with a small screwdriver (red arrow) and pulling the connection straight off.

This area on the underside rear of the intake manifold is sometimes referred to as the magic triangle.
Figure 12

This area on the underside rear of the intake manifold is sometimes referred to as the "magic triangle". You will have to feel around with your hands to find the three bolts to remove them (red arrow, one shown).

Use a set of pliers or Channel Locks and remove the clamp for the coolant hose above the alternator (red arrow).
Figure 13

Use a set of pliers or Channel Locks and remove the clamp for the coolant hose above the alternator (red arrow).

Next, you are going to remove the metal coolant pipe that runs along the top of the intake manifold.
Figure 14

Next, you are going to remove the metal coolant pipe that runs along the top of the intake manifold. Start by removing the 10mm bolt securing it to the front of the intake (red arrow).

You will need to disconnect the metal coolant pipe from where it connects to the rear of the engine.
Figure 15

You will need to disconnect the metal coolant pipe from where it connects to the rear of the engine. There are three 10mm bolts that connect the coolant pipe flange (yellow arrow) to the block (red arrows, two shown). Remove the bolts and pull the pipe out from the motor. Make sure to replace the coolant pipe O-ring when reinstalling.

Remove the vacuum line near the throttle body (red arrow) that goes to the charcoal container.
Figure 16

Remove the vacuum line near the throttle body (red arrow) that goes to the charcoal container.

Loosen but do not remove the support rod for the intake (red arrow).
Figure 17

Loosen but do not remove the support rod for the intake (red arrow). Next, remove the upper bolt (yellow arrow) not shown and swing the rod down out of the way.

Remove the dipstick from the tube (yellow arrow); use care here as the tube gets very brittle from the heat over the years and can easily crack or break.
Figure 18

Remove the dipstick from the tube (yellow arrow); use care here as the tube gets very brittle from the heat over the years and can easily crack or break. Next, remove the two 5mm Allen bolts holding the dipstick bracket to the intake manifold (red arrows).

Depending on the condition of your vehicle, there should be two 10mm nut/bolt combinations on the lower corners of the manifold (red arrows) and then 6mm Allen bolts for the rest (yellow arrows, two shown).
Figure 19

Depending on the condition of your vehicle, there should be two 10mm nut/bolt combinations on the lower corners of the manifold (red arrows) and then 6mm Allen bolts for the rest (yellow arrows, two shown). Regardless of the type, remove all the fasteners connected to the intake.

Remove the intake manifold by rocking it gently until the gasket lets go (red arrow) and then pull the manifold straight back off the head.
Figure 20

Remove the intake manifold by rocking it gently until the gasket lets go (red arrow) and then pull the manifold straight back off the head.

Remove the valve cover from the top of the engine.
Figure 21

Remove the valve cover from the top of the engine. Please see our article on valve cover removal for additional information.

You can remove the turbo from the exhaust manifold by removing the three 15mm bolts (red arrows) and remove the head with the exhaust attached or remove the exhaust manifold from the head.
Figure 22

You can remove the turbo from the exhaust manifold by removing the three 15mm bolts (red arrows) and remove the head with the exhaust attached or remove the exhaust manifold from the head. Either way, please see our article on turbo and exhaust manifold removal for additional assistance.

Loosen all the head bolts slightly in the order shown.
Figure 23

Loosen all the head bolts slightly in the order shown. Do not completely loosen the bolts on the first pass through the order. It should take several repetitions of the order to finally loosen them all and remove them. The head bolts are stretch bolts and single use only. Make sure to use new head bolts when reinstalling. Lift the head assembly slightly and check for any hoses or electrical connections you may have missed. I could not reach this vacuum line and decided to remove it once I had the head in the air. Of course this is much easier to do if you have an engine hoist. If you are lifting the head with the help of a friend, you will need to double check that everything is unattached before you get it in the air. Make sure you have removed the support bracket bolt by the alternator before you try and remove the head.

Notes: Carefully clean the head and block of all old gasket or debris.
Figure 24

Notes: Carefully clean the head and block of all old gasket or debris. Never use a metal scrapper and always take caution not to scratch the head or block. Take care not to get old gasket or cleaning materials into the open ports in the block or cylinders. If the head and block are going to be separated for a length of time, take care that rust does not form on the block. Blow out and clean out all of the head stud holes before installing the head bolts. Use a thread chaser if necessary. If the holes are not clean and dry, it can lead to hydro locking, which can cause serious and terminal damage to the motor.

Remove the old head gasket and install a new one (red arrow), making sure it is seated correctly.
Figure 25

Remove the old head gasket and install a new one (red arrow), making sure it is seated correctly. Do not open the head gasket until you are ready to install it and handle it as little as possible. If you damage the gasket, get a new one before installation as a damaged gasket will just lead to a leaking head.

After you have sent the head out for inspection, properly clean all the mating surfaces and reinstall the head back onto the block taking care to locate the head on the locating pins and to not damage the gasket while doing so.
Figure 26

After you have sent the head out for inspection, properly clean all the mating surfaces and reinstall the head back onto the block taking care to locate the head on the locating pins and to not damage the gasket while doing so. Use the appropriate head bolt lubricant and install the bolts according to the diagram. You must torque the head bolts to certain specifications. Check for the proper torque values for your head and follow those instructions carefully. Installation of all the other components is the reverse of removal.










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Comments and Suggestions:
JazzmanG Comments: what is the tightening torque for A4 cylinder head.
August 31, 2016
  Followup from the Pelican Staff: I don’t have that info.


I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
SycoSez Comments: Is there any major difference between the job on a 2001 B5
July 22, 2016
  Followup from the Pelican Staff: What engine and model do you have? - Nick at Pelican Parts  
Taz3 Comments: Audi 1.8 avj
the gasket is new
April 21, 2016
  Followup from the Pelican Staff: I would assume the valve guide for the valve that fails is worn. - Nick at Pelican Parts  
Taz3 Comments: I replace the gasket with new one and i have problem with exhaust valve. I started the car and after 5 hours the exhaust vavle was cut off from the top. I change all exhaust valve. I started the car and again the same shit. The timming of chain and belt was ok !
April 21, 2016
  Followup from the Pelican Staff: What vehicle? You may have a bad valve guide. - Nick at Pelican Parts  
Audiwan Kenobi Comments: ok,I'll have it checked out today,thanks!
May 13, 2015
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Audiwan Kenobi Comments: What's up!...your write ups are the best there is...


I'm doing my HG because I suspect that that's where my oil leak is coming from.it's at the back left of the motor and I've replaced all other gaskets.it never over heated or mixed fluids to my knowledge so my question is:is it necessary to send the head off to be machined?...could the head crack in that area to cause it to leak like that? I have read other diys that said it wasn't necessary to have it machined if no over heating occurred.Your opinion reigns supreme so I'll wait aday or 2 for it,thanks
May 8, 2015
  Followup from the Pelican Staff: I would suggest having it at least checked for straightness. No need to machine it the sealing surface is in good shape. - Nick at Pelican Parts  

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