DIY: Removing the head from D2 A8 (AUX) and valve job
03-29-2021, 04:23 AM
#1
AudiWorld Junior Member
Thread Starter
DIY: Removing the head from D2 A8 (AUX) and valve job
For those of you tracking my issue with timing and then major f up, here is what I did over the past several days to rescue the car.
Car runs again with the help of several DIYs from this site and youtube (Thanks for A8 timing belt DIY and torque spec discussions). See those posts when rebuilding your engine. I have included as much as I could in one place for your convenience. Feel free to make additions or ask questions. I am not a professional mechanic, but interested in cars and decided to keep this low mileage D2 A8 from the scrap yard.
D2 A8 4.2 40v Valve Head removal (Driver side) – Passenger side would be the same basic process except for removal of the actual head from the car. Not sure if the clearance issues would be better or worse, but there is the rigid coolant pipe that attaches at 2 places along the side and mounts to the rear of EACH head using 2 allen bolts. It's a rigid pipe so if removing the driver side head, then you only need to remove the two bolts.
1) Remove all of the things you normally would to take off the coil pack, including wires
2) Disconnect air intake hose
3) Prepare to remove intake chamber
a. Mark where all hoses go and take pictures. I put tape on each hose and letter coded so I could get them back in place. When you reassemble the engine, you’ll likely have a couple of hoses free and scratch you head. A to A, B to B, et cetera. Writing on the intake with Sharpie works for those plugging into the intake. There are a lot of connectors, I will not detail them all, but recommend marking what each is and where it goes.
4) Undo the two hoses to the fuel rail along the passenger side near firewall
a. One has crimped hose the other fuel line is 17mm
b. Third hose attaches to the tube at back of the intake chamber, disconnect allen bolt holding the tube from intake chamber
5) Unbolt the fuel rail (4x 10mm). The brown Beru things are capacitors to help with radio while from alternator. Not the end of the world if the wire breaks, but annoying fragile on a 20 year old car
6) Unplug green cable that is built into fuel rail
a. The 3 prong wire can be pulled straight out from the front. The housing itself is held to the metal of the fuel rail by a retainer. It’s hard to remove without breaking. Again, 20 year old plastic can be brittle.
7) Spray a little fogging oil, WD40 or other intake/engine safe lubricant into fuel injector mounts and wiggle, let the oil seep in to make removal easier. Pull straight up on the fuel rail while wiggling. Technically you could leave the injectors in place, but very difficult to remove injector wires without lifting it up from the intake chamber.
8) Disconnect the injector wires. Note which cable is which near cylinder #5 injector. It is easy to confuse with other 2-3 sensors when putting back. Frustrating to remove injector rail again, so mark everything.
9) Unbolt the intake chamber from the engine using only the allen bolts surrounding it, not the torx. The torx bolts hold the intake unit together.
10) Remove hoses from the back of intake including big air intake from filter housing and 90 degree vacuum hose elbow. There are no hoses underneath the air intake chamber on the AUX 4.2 engine, your engine may differ.
11) Gently pull up intake chamber unit to ensure you’ll disconnected everything
12) Remember the intake passages to the cylinders will be exposed. Crap can and will fall in. If valves are open, dirt and such could enter cylinder chambers. Have a strong vacuum on hard. Plug open intake holes with lint-free rags.
13) Removing the head
14) This part sucks…you’re doing a full timing belt job
a. Service position. You should drain coolant now, but I just pulled front carrier away without fully removing the radiator hose. It worked…for me.
b. Put engine at TDC…not 180 degrees from TDC, #5 Cyl at top of stroke. Ensure notch on crank pulley lines up with cover > so that you see --- > where the crank pulled line is centered on the “V” in the plastic cover. The camshaft wings must line up and accept the lock bar. Once bar is fitted, install the crank lock pin. I like to wiggle the crank a little until the lock pin seats fully.
c. Remove fan (32mm?). You’ll probably need the special pin tongs, but you might get lucky.
d. Remove fan pulley (3 X 10mm)
e. Remove crank pulley (it’s keyed, so you know approx. where it goes back...but you locked the crank at TDC, right? Right?
f. Remove serpentine tensioner pulley unit
g. Remove the engine vibration mount top bolt (17mm?) and 3 bolts holding unit to engine (3 X 13 or 14mm bolts?) – remove the whole unit to access tensioner
h. Use long try bar with allen to depress hydraulic tensioner in counterclockwise direction
i. Once down, stick pin or very small allen key to hold tensioner pin in place
ii.
i. Remove timing belt from head
j. I pulled the camshaft pulley too, but not required
k. I highly recommend you order new parts including a belt now because everything is exposed anyway
l. Not sure, but I think the black metal housing behind the timing belt has to be removed. Remove the 3 bolts around the timing camshaft pulley (3 x 10mm)
m. Loosen the two lower 10mm nuts holding lower housing to the engine
15) If valve cover isn’t off, pull it. You’ll have more room to work in the back. Throw an old T-shirt over to protect things while working above the cams.
16) Remove vent hoses from front and back of valve cover
a. I left the front vent hose between the two heads in place and pulled hose off the passenger side only because it had a worm screw clamp and not a crimp.
17) Remove the Kombi valve
a. Unplug small vacuum hose
b. Remove the two small allen bolts from the kombi vent pipe. Careful not to lose the small gasket
c. Remove 3 allen bolts from Kombi to head – it’s easier to remove the 2 heater core hoses, pull them aside to make some room for your hands.
18) Remove the two allen bolts from the black coolant pipe
a. The bolts are only accessible once the Kombi valve has been removed. You cannot reach one of the bolts if kombi still attached. I have a donor AUX engine that I could walk around and there isn’t any way to undo black coolant pipe with Kombi installed.
19) Disconnect bolt holding oil dipstick from head (13mm, I think)
a. It can be twisted out of the way, being careful not to damage where it inserts at the engine base
20) Remove exhaust manifold
a. You have two options: 1) leave the manifold on the head and 2) unbolt the manifold and see if there is room to slide it off the studs. I only tried Option 1, so I cannot be certain Option 2 is viable
b. Exhaust bolts were easier than expected. I believe it’s a 13mm nut. 1 of 3 is accessible from the top. You’re best bet is to lie on the ground and reach up through the wheel well. Nuts 2 and 3 of 3 are pretty accessible and came off easily (for me).
21) Remove head bolts
a. Here is where is gets interesting. I bought a long (7”) triple square tool (10mm) to remove the head bolts. It worked great on the ‘donor’ engine out of the car, but you cannot reach two of the bolts with the engine in the car because of clearance with shock tower housing. A 4” (total length of tool) 10mm TS is available. I ended up having to buy both. However, the short tool only works with the camshaft caps off. So you could buy the short one, but be prepared to remove the camshafts. Not a terrible idea because it will remove some weight.
b. Once the head bolts are out the head should be free. It probably weighs 100 lbs with the exhaust and cams in place. Be prepared, but at least you don’t have to worry about the old head gasket.
c. Remember, the three exhaust bolts requires you to lift the head and pull forward which is tricky because of the weight. If you have a shop crane, use it to save your back.
22) Replacing Valves
23) To access the valves, you must remove the camshaft caps which is done with torx bolts and the camshaft sensors cover too. Remember to have all of your gaskets to refit on the camshafts and tensioner (including ½ moon gasket) when done servicing valves
24) Remove rockers
a. With camshafts out of the head you will see the rockers. They are held in place by two long rods. Each rod is held in place by an allen bolt that is offset from the center. Remove this small allen bolt from each end and screw into the center (hole next to where bolt was) about until slightly tight. Now gently tighten and loosen until the shaft is moving with you in the direction you are turning the bolt. That means the shaft is loose and will pull out. To pull out, put a flat screwdriver against the head and the allen bolt and gently pry until the rod pops. Remove shaft and place the rockers back onto the rod in the order they were in. Set both aside…don’t worry, you cannot mix intake and exhaust up, the intake has 3 contacts and the exhaust has 2 contacts.
25) Remove springs
a. I read that the special Lisle tool you pound with a mallet doesn’t work with the Audi springs. I cannot comment as I didn’t try one. I did buy the C-clamp style because I’ll attempt to do the came job on an old Ford flathead.
b. Compress spring and use a magnet to get the two retainer clips out. They’re small so have a container you can seal ready. Don’t lose the little clips.
c. Once spring is loose, you can press the valve out.
d. Clean valves by putting them into a drill after you put a little duct tape on the shaft to protect it from drill chuck. Scratches could cause some oil leaking which is no good. Check valves are straight by spinning in drill. While spinning, I put the valve end and face (not the shaft!) against a brass brush on the bench grinder. It cleaned up pretty good.
e. Learn to ‘lap’ (seat) valves with grit compound and manual or automatic method. Clean and replace.
f. Replacing springs is tough. Compress and return the two clips into valve grooves. I found some synthetic grease in the valley of the valve clip will help them to stick to valve. Also, some grease on a small screw will keep the clip on the end of the tool, but release once the clip sticks to valve shaft and grooves. Be patient, this is a slow process.
g. Now do everything in reverse…
26) Clean up all the passages to remove the build up. I even used a dremel with small wire brush to clean the head's intake and exhaust ports (very carefully near the valve seats).
27) Bon chance
Car runs again with the help of several DIYs from this site and youtube (Thanks for A8 timing belt DIY and torque spec discussions). See those posts when rebuilding your engine. I have included as much as I could in one place for your convenience. Feel free to make additions or ask questions. I am not a professional mechanic, but interested in cars and decided to keep this low mileage D2 A8 from the scrap yard.
D2 A8 4.2 40v Valve Head removal (Driver side) – Passenger side would be the same basic process except for removal of the actual head from the car. Not sure if the clearance issues would be better or worse, but there is the rigid coolant pipe that attaches at 2 places along the side and mounts to the rear of EACH head using 2 allen bolts. It's a rigid pipe so if removing the driver side head, then you only need to remove the two bolts.
1) Remove all of the things you normally would to take off the coil pack, including wires
2) Disconnect air intake hose
3) Prepare to remove intake chamber
a. Mark where all hoses go and take pictures. I put tape on each hose and letter coded so I could get them back in place. When you reassemble the engine, you’ll likely have a couple of hoses free and scratch you head. A to A, B to B, et cetera. Writing on the intake with Sharpie works for those plugging into the intake. There are a lot of connectors, I will not detail them all, but recommend marking what each is and where it goes.
4) Undo the two hoses to the fuel rail along the passenger side near firewall
a. One has crimped hose the other fuel line is 17mm
b. Third hose attaches to the tube at back of the intake chamber, disconnect allen bolt holding the tube from intake chamber
5) Unbolt the fuel rail (4x 10mm). The brown Beru things are capacitors to help with radio while from alternator. Not the end of the world if the wire breaks, but annoying fragile on a 20 year old car
6) Unplug green cable that is built into fuel rail
a. The 3 prong wire can be pulled straight out from the front. The housing itself is held to the metal of the fuel rail by a retainer. It’s hard to remove without breaking. Again, 20 year old plastic can be brittle.
7) Spray a little fogging oil, WD40 or other intake/engine safe lubricant into fuel injector mounts and wiggle, let the oil seep in to make removal easier. Pull straight up on the fuel rail while wiggling. Technically you could leave the injectors in place, but very difficult to remove injector wires without lifting it up from the intake chamber.
8) Disconnect the injector wires. Note which cable is which near cylinder #5 injector. It is easy to confuse with other 2-3 sensors when putting back. Frustrating to remove injector rail again, so mark everything.
9) Unbolt the intake chamber from the engine using only the allen bolts surrounding it, not the torx. The torx bolts hold the intake unit together.
10) Remove hoses from the back of intake including big air intake from filter housing and 90 degree vacuum hose elbow. There are no hoses underneath the air intake chamber on the AUX 4.2 engine, your engine may differ.
11) Gently pull up intake chamber unit to ensure you’ll disconnected everything
12) Remember the intake passages to the cylinders will be exposed. Crap can and will fall in. If valves are open, dirt and such could enter cylinder chambers. Have a strong vacuum on hard. Plug open intake holes with lint-free rags.
13) Removing the head
14) This part sucks…you’re doing a full timing belt job
a. Service position. You should drain coolant now, but I just pulled front carrier away without fully removing the radiator hose. It worked…for me.
b. Put engine at TDC…not 180 degrees from TDC, #5 Cyl at top of stroke. Ensure notch on crank pulley lines up with cover > so that you see --- > where the crank pulled line is centered on the “V” in the plastic cover. The camshaft wings must line up and accept the lock bar. Once bar is fitted, install the crank lock pin. I like to wiggle the crank a little until the lock pin seats fully.
c. Remove fan (32mm?). You’ll probably need the special pin tongs, but you might get lucky.
d. Remove fan pulley (3 X 10mm)
e. Remove crank pulley (it’s keyed, so you know approx. where it goes back...but you locked the crank at TDC, right? Right?
f. Remove serpentine tensioner pulley unit
g. Remove the engine vibration mount top bolt (17mm?) and 3 bolts holding unit to engine (3 X 13 or 14mm bolts?) – remove the whole unit to access tensioner
h. Use long try bar with allen to depress hydraulic tensioner in counterclockwise direction
i. Once down, stick pin or very small allen key to hold tensioner pin in place
ii.
i. Remove timing belt from head
j. I pulled the camshaft pulley too, but not required
k. I highly recommend you order new parts including a belt now because everything is exposed anyway
l. Not sure, but I think the black metal housing behind the timing belt has to be removed. Remove the 3 bolts around the timing camshaft pulley (3 x 10mm)
m. Loosen the two lower 10mm nuts holding lower housing to the engine
15) If valve cover isn’t off, pull it. You’ll have more room to work in the back. Throw an old T-shirt over to protect things while working above the cams.
16) Remove vent hoses from front and back of valve cover
a. I left the front vent hose between the two heads in place and pulled hose off the passenger side only because it had a worm screw clamp and not a crimp.
17) Remove the Kombi valve
a. Unplug small vacuum hose
b. Remove the two small allen bolts from the kombi vent pipe. Careful not to lose the small gasket
c. Remove 3 allen bolts from Kombi to head – it’s easier to remove the 2 heater core hoses, pull them aside to make some room for your hands.
18) Remove the two allen bolts from the black coolant pipe
a. The bolts are only accessible once the Kombi valve has been removed. You cannot reach one of the bolts if kombi still attached. I have a donor AUX engine that I could walk around and there isn’t any way to undo black coolant pipe with Kombi installed.
19) Disconnect bolt holding oil dipstick from head (13mm, I think)
a. It can be twisted out of the way, being careful not to damage where it inserts at the engine base
20) Remove exhaust manifold
a. You have two options: 1) leave the manifold on the head and 2) unbolt the manifold and see if there is room to slide it off the studs. I only tried Option 1, so I cannot be certain Option 2 is viable
b. Exhaust bolts were easier than expected. I believe it’s a 13mm nut. 1 of 3 is accessible from the top. You’re best bet is to lie on the ground and reach up through the wheel well. Nuts 2 and 3 of 3 are pretty accessible and came off easily (for me).
21) Remove head bolts
a. Here is where is gets interesting. I bought a long (7”) triple square tool (10mm) to remove the head bolts. It worked great on the ‘donor’ engine out of the car, but you cannot reach two of the bolts with the engine in the car because of clearance with shock tower housing. A 4” (total length of tool) 10mm TS is available. I ended up having to buy both. However, the short tool only works with the camshaft caps off. So you could buy the short one, but be prepared to remove the camshafts. Not a terrible idea because it will remove some weight.
b. Once the head bolts are out the head should be free. It probably weighs 100 lbs with the exhaust and cams in place. Be prepared, but at least you don’t have to worry about the old head gasket.
c. Remember, the three exhaust bolts requires you to lift the head and pull forward which is tricky because of the weight. If you have a shop crane, use it to save your back.
22) Replacing Valves
23) To access the valves, you must remove the camshaft caps which is done with torx bolts and the camshaft sensors cover too. Remember to have all of your gaskets to refit on the camshafts and tensioner (including ½ moon gasket) when done servicing valves
24) Remove rockers
a. With camshafts out of the head you will see the rockers. They are held in place by two long rods. Each rod is held in place by an allen bolt that is offset from the center. Remove this small allen bolt from each end and screw into the center (hole next to where bolt was) about until slightly tight. Now gently tighten and loosen until the shaft is moving with you in the direction you are turning the bolt. That means the shaft is loose and will pull out. To pull out, put a flat screwdriver against the head and the allen bolt and gently pry until the rod pops. Remove shaft and place the rockers back onto the rod in the order they were in. Set both aside…don’t worry, you cannot mix intake and exhaust up, the intake has 3 contacts and the exhaust has 2 contacts.
25) Remove springs
a. I read that the special Lisle tool you pound with a mallet doesn’t work with the Audi springs. I cannot comment as I didn’t try one. I did buy the C-clamp style because I’ll attempt to do the came job on an old Ford flathead.
b. Compress spring and use a magnet to get the two retainer clips out. They’re small so have a container you can seal ready. Don’t lose the little clips.
c. Once spring is loose, you can press the valve out.
d. Clean valves by putting them into a drill after you put a little duct tape on the shaft to protect it from drill chuck. Scratches could cause some oil leaking which is no good. Check valves are straight by spinning in drill. While spinning, I put the valve end and face (not the shaft!) against a brass brush on the bench grinder. It cleaned up pretty good.
e. Learn to ‘lap’ (seat) valves with grit compound and manual or automatic method. Clean and replace.
f. Replacing springs is tough. Compress and return the two clips into valve grooves. I found some synthetic grease in the valley of the valve clip will help them to stick to valve. Also, some grease on a small screw will keep the clip on the end of the tool, but release once the clip sticks to valve shaft and grooves. Be patient, this is a slow process.
g. Now do everything in reverse…
26) Clean up all the passages to remove the build up. I even used a dremel with small wire brush to clean the head's intake and exhaust ports (very carefully near the valve seats).
27) Bon chance
Last edited by Homegrown-MN; 03-29-2021 at 04:27 AM.
The following users liked this post:
vicsvinyl (10-07-2022)
10-07-2022, 08:01 AM
#2
Head bolt tool
Bought one online for my 2001 A8L D2 4.2L. Fits my A61999 avant 2.8L.
Will not fit A8 Anyone have a number or link to one. It's out of car, just need to lighten for moving.
Will not fit A8 Anyone have a number or link to one. It's out of car, just need to lighten for moving.
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