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|07-20-2006, 02:50 PM||#1|
New MemberGarage is empty, add now
Join Date: Sep 2005
Has anyone done a headgasket?
|07-20-2006, 04:19 PM||#2|
AudiWorld Senior MemberGarage is empty, add now
Join Date: Mar 2002
Re: Has anyone done a headgasket?
Depending on your level of confidence, based on doing other things on the car, it can be a PITA.
If you are novice, you might want to find someone to help you.
Here are some jobs that are far simpler. have you done these?
take off and clean EGR?
replace strut inserts?
do timing belt replacement
lower control arm replacement?
If you feel comfortable with all of the above, you are ready to take a head off.
bear in mind to a really good set of tools, you need some special tools. To take the old head bolts out, you need a torx like tool. To put the new head bolts in, (they must be new), you need yet a different torx like tool.
If you haven't figured this out yet, Audi like to invent new tools for things. Oh, and with the head(s) off, you'll need the timeing belt alignment tool.
Don't want to discourage you, but taking the head off is not a beginer job.
Start by taking all the crap off the top, wires, hoses, connectors, fuel injection rails, air plenum, and throttle body.
drain and remove collant hoses
go underneath and disconnect the exhaust manifold to pipe.
take off the EGR and down tube.
disconnect the coolant pipes from the back of the heads and back up the pipes which sorta stick into the front.
take off the power steering pump and hoses. no need to disconnect them. just move to the side and keep them connected.
take off the valve covers.
with everyting off the top, take off the intake manifold bolts and pry off the IM. try to get it to come straight up, not at an angle.
there is some heat sheild crap along the exhuast manifold that you'll sacrifice some skin on.
take off the timeing belt. per the correct proceedure while the engine is on top dead center with the holding tool in the crank position hole.
finally, you are ready to loosen the head bolts. do it carefull and make sure the torx like tool is seating down in the bolt. otherwise, you might round one out. then, you'd really have a mess.
take head off with the exhaust manifold connected. it will clear the sides, but you need to wiggle it around.
replace the valley pan gasket while you are in there and the oil seal on the back of the passenger side head. it always leaks.
as they say in the funny pages, installation is reverse of dissassembly.
that is a high level overview and i probably missed something. as you take stuff off, it will become evident of what is in the way. i did this from memory and don't own a c-4 anymore.
|07-20-2006, 06:26 PM||#3|
New MemberGarage is empty, add now
Join Date: Sep 2005
Thanks Jim it helps
I am not that green, its better to be safe than sorry. I have mostly worked on Hondas and the old Audi 5 cylinders. This is challenging and I am trying to do as much research before tearing it apart. Once again thanks for the pointers it really helps.
|07-20-2006, 06:33 PM||#4|
Garage is empty, add now
Join Date: Oct 2002
Check the head for warpage before you have it cut. They rarely need milling.
Growing old is mandatory; growing up is optional.
2005 A6 Sedan Q 3.2 (wife's whip)
2000 A4 Avant Q 2.8 (daily driver)
1980 VW Scirocco (mid-life crisis car)
1983 Mazda RX-7 (revolutionary sports car)
2003 Mini Cooper S (just because)
1995 Mazda Miata, Superdupercharged(anti-Audi)
1999 Mazda Miata SSB (track beotch, no plate)
2003 GMC Yukon Denali XL (the anti-earth)
2004 Dodge Dakota (hey, at least it's stick and 4x4)
|07-20-2006, 06:43 PM||#5|
New MemberGarage is empty, add now
Join Date: Sep 2005
step by step head gasket replacement
a friend of mine recently asked me to change his headgaskets, so i assembled all of the following from the 12v.org pages to explain to him why i wouldn't do it. everything that follows was written by the 12v.org person, not me:
Please read through all of the instructions here and make sure you understand them before attempting this procedure!
The most common mode of failure of 12v head gaskets is oil leaks. Unless there has been some sort of catastrophic cooling system failure, you tend not to see many blown head gaskets or coolant leaks. If you suspect that coolant is leaking from your head gaskets, you can check your engine oil to see if it is foamy (thus coolant is leaking into the oil passages), or pull each spark plug and check to see if one is unusually clean (thus coolant is leaking into the combustion chamber, and the plug is steam cleaned several hundred times per minute).
Most people associate replacing head gaskets with huge repair bills or huge amounts of work. Those people are right. Replacing your head gaskets is a very involved process, requiring lots of tools, time, replacement parts, common sense, and repair experience. You will be removing a large percentage of your engine to get to the gaskets, and will probably break something, lose something, or encounter one or more parts or tools that you need but don't have. This is not the job to do if you've never worked on your car before.
Those of you who aren't checking the balances on your credit cards to see if you can afford to have your favorite mechanic to do it have probably already rolled your eyes in disgust and started scrolling down to the procedure, because you are crazy.
To the right-thinking people who are approaching this procedure with a certain amount of trepidation, it's not actually as horrible as it sounds. It's merely bad. Just remember: preparation, knowledge, and common sense are sufficient to succesfully complete any repair task. This article will help with the first two; for the latter you're on your own.
Definitions and Acronyms:
* TDC: Top Dead Center. This is the position of the engine when the #1 cylinder is up as far as it will go.
* EGR: Exhaust Gas Recirculation. The EGR valve lets exhaust gasses back into the intake manifold under certain conditions to lower combustion temperature and NOx emissions.
* NOx: Nitrous Oxide
* ISV: Idle Stabilizer Valve. An electric valve controlled by the ECU to allow extra air through the intake manifold under certain conditions, to keep the engine from stalling. Also called the Idle Air Control (IAC) valve.
* Torque wrench. I recommend getting one with a 1/2 inch drive, or the head bolts will be fairly hard to install.
* Triple-square sockets. You may or may not need these; some head bolts will use them; others will use a normal hex socket. You can see which you have by removing the valve cover.
* Various sockets. I recommend 6-point sockets whenever possible, as you will be less likely to round off tight or stuck bolts or nuts.
* Various extensions and adapters for sockets
* 5mm, 6mm, and 8mm allen wrench sockets.
* Magnetic pick-up tool. Trust me, this is just a good thing to have.
Tools noted in the timing belt replacement procedure
* 5mm, 6mm, 8mm, and 10mm allen wrench sockets (that go on your favorite ratchet ... regular allen wrenches won't do)
* 10"-12" socket extension
* Flexible socket extension
* 10mm 6-point deep hex socket (or shallow socket with a short extension)
* 24mm (or 15/16") 12-point socket
* A torque wrench to go with all of those
* Crankshaft holding tool, Audi #3242 or equivalent
* Camshaft holding tool, Audi #3243 or equivalent (these two tools can be rented from some parts suppliers)
* Two large buckets
* Safety glasses
* Big flat head screwdriver
* Channel locks
* Camshaft sprocket puller (available at most auto parts stores)
* A small razor blade with a long handle ... I have one that's made for scraping window glazing that works quite well
* [insert your favorite method of lifting the car a few inches here]. Make sure it's a safe method (i.e. no cement blocks or foot stools)
* A spare mode of transportation is helpful, in case anything goes wrong an you have an emergency trip to your parts shop or mechanic.
Tools noted in the oil check valve replacement procedure
* Phillips head screwdriver
* 6mm allen wrench socket
* 8mm Allen wrench socket
* 10mm open-ended wrench
* 17mm open-ended wrench
* 19mm open-ended wrench
* 10mm 6-point socket
* Assorted socket extensions and flex adapters
* Long needlenose pliers, magnetic pick-up tools, and/or alligator forceps
* Slip-joint pliers or Channel Locks
* Razor Blade
* Paper Towels
* 2 Rubber bands (2"-4" or 5mm-10mm diameter)
* Small jar or can (i.e. a jam jar)
* Head gaskets. You want to replace both of them, not just one.
* Camshaft oil seals
* Intake manifold gaskets
* Valley pan gasket. Technically, you don't need to replace this. However, it's cheap, and you'll be right there.
* EGR valve gasket
* Valve cover gasket
* Lots of assorted vacuum hose
* Head bolts. 8 per head. These are not optional! They are single use only.
* Silicone grease
Parts noted in the timing belt replacement procedure
* Timing belt
* Accessory drive belt (why not; you're there, right?)
* Water pump
* Water pump gasket
* Coolant thermostat
* Thermostat O-ring
* Timing belt tensioner
* ~1 gallon of antifreeze (phosphate free antifreeze that is safe for aluminum engines)
* ~1 gallon of distilled or de-ionized water
* Rubber O-ring for the coolant drain plug on the engine block
Parts noted in the oil check valve replacement procedure
* Head -> intake manifold gaskets (set of two)
* EGR -> intake manifold gasket
* Valley pan gasket
* Check valves (2)
* Throttle Body -> intake manifold gasket (optional)
* 3/16" (~3mm) ID rubber vacuum tubing -- about 1 foot (30cm) should do
Many parts suppliers sell a 'head gasket kit' that combines many of these parts into a less expensive package. Ask around.
1. First, Stare at the engine and make sure that you're familiar with where everything is. Do this periodically throughout the procedure, so that there's less likely to be any question of how things fit back together. This is an important step that many people forget - and regret later. Grab a pencil and some paper so that you can make notes and draw pictures while you're working.
2. Follow steps 1-20 of the timing belt removal procedure (steps 1-24 if you have a Coupe, Cabriolet, 80, or 90). This gets you as far as draining the coolant, making some room in the engine bay, and removing the timing belt. It's probably worth draining the oil in addition to draining the coolant, even though the timing belt procedure doesn't call for it.
Timing belt 1-20 Procedure:
1. Remove the big plastic cover that goes under the engine, then remove the bracket that holds the back of it to the engine block. You'll see a deeply recessed 8mm allen bolt at the back of the engine block on the left hand side of the car; that's the drain plug for the radiator fluid. You'll need the 8mm allen wrench socket, long socket extension, a large bucket, and your safety goggles now. Put on the goggles (antifreeze will spray everywhere) and get the bucket as close as you can to the plug. It's hard to get the wrench to fit in the hole where the plug is, but remember that it will be a lot harder to get the plug out if it's stripped so make sure you've got the wrench seated before trying. It takes a bit of work but it will come out. Get the fluid draining into the bucket, and then remove the radiator cap. Go inside (if your spouse will let you), wash your hands, and eat lunch while the fluid drains.
2. Get another bucket. On the bottom right (as you're looking at the front of the car) of the radiator there's a red thumb screw connected to a miniature faucet. That's the other drain plug. Put the bucket under the faucet and loosen the thumb screw. If it looks like the bumper will get in the way, you can stick a piece of rubber tubing over the end of the faucet and use that to send the fluid into the bucket.
3. At the top center of the firewall, there are two 1" hoses going through the firewall. One of them has a bleeder screw on top (sometimes ... in some cars this bleeder is omitted). Twist the screw -- it will break off in your hand. That'll be $50 because the screw comes with the hose. I was fortunate to have another plastic screw with the same threads (I don't know where it came from or what it was for, but it fit just right). You may be fortunate enough to not have this one break, but be prepared for it. Anyway, this is a bleeder screw -- loosen it to help remove more fluid.
4. Peer down behind the right side (as you're standing at the front bumper) cylinder head, and you'll see the coolant line that comes off the back of the block. It makes a 90 degree bend towards the middle of the engine, and just after that bend there's a sensor, and then a little screw with a big head (maybe 10-12mm) with a 5mm allen head on it -- this is the other bleeder. You'll want your long socket extension to loosen this. Only loosen it a turn or two, because if it falls, it will be immediately warped to that other dimention where socks that get lost in the dryer go, and you'll never see it again.
5. Remove the first layer of plastic covers on the front of the engine to expose the accessory belt.
6. Mark the direction that the accessory belt is mounted unless you're replacing it -- if you put it back on, it's got to go the same direction!
7. On the tensioner for the accessory belt, there's a spot for a wrench. On pre-1995 cars, it's a 10mm allen wrench. On post-1995 cars, it's a 17mm socket. Twist the tensioner clockwise (pre-1995) or loosen the bolt (post-1995) to release the tension on the belt. Remove the accessory belt.
8. Remove the accessory belt tensioner using a 10mm allen socket.
9. Now remove the timing belt covers. There are metal clips on the top and bottom of each side. Start with the cover on the right side of the engine (as you're looking from the front of the car). Unclip, pull up, and wiggle them around until they either come free or break. If they break, make sure you get all of the little bits of plastic out! The bottom cover comes off last.
10. Get the 24mm (or 15/16") socket and twist the crankshaft CLOCKWISE (as you're standing at the front bumper) until cylinder 1 is at TDC. At TDC you'll notice that the oblong plates at the ends of the camshafts are pointing towards each other, with the big hole on each closer to the center of the engine. Also there's a little notch scratched in the accessory belt's main pulley that correponds to a little arrow in the plastic cover that's mounted directly behind it.
11. Crawl back under the engine with a flashlight, a 10mm socket, the flexible socket extension, your ratchet, channel locks, and the crankshaft holding tool. Look around the right side of the engine block until you see the crankshaft position sensor, which is mounted near the middle of the engine block, up and back from the oil pan. It's long and flat and has a big wire sticking out one end, and a 10mm hex bolt in the other. Remove the hex bolt, and pull the sensor straight out with the channel locks. Screw the crankshaft holding tool in where the sensor was. If it won't go in, probably the crankshaft is not at TDC -- rotate it so that the camshafts do a complete revolution and it should be ready.
12. Remove the 8 6mm bolts that hold the main pulley/vibration dampener on the front of the crankshaft. Remember that it's heavy, so don't have your feet under it.
13. Attach the camshaft holding tool.
14. Note the tension on the timing belt. You should be able to twist it 90 degrees without too much difficulty.
15. Loosen (don't remove it yet) the bolt that holds the timing belt tensioner in place. The tensioner will move! Don't worry.
16. Pull the timing belt off the tensioner, then off the crankshaft sprocket, then the other idler pulley. Loosen the belt around the camshaft sprockets and water pump so that it isn't mounted on anything.
17. Use a 24mm wrench to loosen the bolts holding the camshaft sprockets on to the camshafts about 2 turns. DON'T REMOVE THE BOLTS, just loosen them a bit.
18. Carefully remove the camshaft holding tool.
19. Use your sprocket puller to carefully release the camshaft sprockets. They are not keyed to the camshafts -- the camshafts have tapered ends that the sprockets are stuck on. When you release the sprockets (they will come off with a heart-stopping bang; don't worry! You haven't broken anything unless the camshafts moved) they will be able to spin freely while the camshafts stay in place.
20. Remove the timing belt.
3. Follow steps 1-23 of the oil check valve replacement procedure. This gets the intake manifold off. If you are replacing the valley pan gasket, also do steps 24 and 25. You can replace those valves, too, but I wouldn't bother unless you really want to. If you took the valley pan cover off to replace the gasket, put it back on before continuing.
Oil Check valve (1-23 procedure)
1. * Remove the plastic covers that are on the top of engine.
2. * Remove the large flexible hose that runs from the Mass Air Flow (MAF) sensor to the plastic manifold behind the throttle body. If your car does not have a MAF sensor , this is the large hose that runs from the airbox to the plastic manifold behind the throttle body.
3. * Remove the camshaft breather tubes (fairly large tubes that run from the top of each head to the plastic manifold behind the throttle body). In some cars, one or both of the tubes are hard plastic. These have something like a child-proof cap on each end; you squeeze the two sides of it and pull straight back. Be careful, though, because these are prone to cracking.
4. * Remove the black plastic tube that sticks out of the top passenger's side of the plastic manifold behind the throttle body.
5. * Remove the two 10mm bolts that connect the top of the plastic manifold to the intake manifold.
6. * Pull the plastic manifold straight back (towards the firewall) about 1 inch until it is free of two metal posts on the bottom of the throttle body. Beware that the manifold has a rubber grommet for each of these posts and the grommets might fall. Keep an eye on them so that you can catch or retrieve them if this happens. Actually, that's not true; if one of the grommets falls, you will probably never see it again because it will have somehow lodged itself into a tiny crevace near the transmission. Just be careful so that they don't fall.
7. * Remove the two 10mm bolts that hold the EGR valve onto the intake manifold. This could take some time -- as you work on it, you'll find yourself cursing and bleeding a lot, and your back will start to hurt from bending over the engine bay, and you'll try the open ended wrench and then the 10mm socket and then the socket with some combinations of adapters and extensions, and suddenly everything will fall into place and the bolts will come right out. Throw away the gasket.
8. * Now you need to disconnect the fuel supply and return lines. You'll note that they are different lengths, so you'll be able to tell later on which goes where. For each hose, one side needs the 17mm open-ended wrench and the other side needs the 19mm open-ended wrench. Usually there isn't much pressure here if the engine is cold, but beware that fuel may squirt out at you when you loosen one of the hoses! No smoking now or you'll be sorry. Remember that even if no fuel sprays out, vapors will and it's the vapors that catch fire. At any rate, when you disconnect each fuel line, have your jam jar ready and stick the end of the hose in the jar so that gas doesn't spill all over the engine. Resist the temptation to hold the hoses down to drain fuel out of them -- remember that you're going to have to start the car eventually, and the less air you have in the fuel system, the easier that will be.
9. * Wrap the ends of the fuel lines and fuel rail with 2-3 paper towels and secure the towels with a rubber band. This keeps gas from dribbling, and keeps dirt and other bad stuff from getting in the fuel system.
10. * Now disconnect the throttle cable. There are two little metal clips that hold the end of the cable onto a plastic banana-shaped arm -- make sure you catch them both. Beware that they would rather fly off into the distance than be put back on, so keep a good grip on them lest they liberate themselves. Follow the cable back to a rubber grommet near the passenger's side of the engine that's mounted on a metal bracket. It takes a bit of twisting but this will come off. Don't garbage up the rubber grommet!
11. * Near that grommet there's a ground point; it's a 10mm bolt with blue paint on it and several brown wires coming off connectors that are under it. Remove the bolt and free the wires.
12. * Unplug the green wiring harness that's near the cruise control vacuum ball.
13. * Disconnect the colored plastic tubes from the colored rubber hoses for the intake manifold changeover valve, the cruise control actuator, and the EGR valve. You'll note that these are color-coordinated so that it's easy to put them back on. Handy, huh? Well, forget it. Rip off the colored rubber tubes and replace them with new vacuum tubing. Then remember which color tube went where! Actually you may want to hold off on replacing these until the end, if you're worried that you won't remember which color goes to which vacuum assembly.
14. * Disconnect the two-wire harness connector that's plugged in to the top of the Idle Stabilizer Valve (ISV).
15. * Reach behind the throttle body and disconnect the wiring harness that's plugged into the bottom of it.
16. * Disconnect the vacuum hose that runs from the left side of the throttle body to the bunch of valves near the MAF sensor. Be careful with this hose because it's 1/4" ID on one side and 3/8" on the other, so if something happens you'll have to kludge something together to fix it.
17. * If your car has an automatic transmission, there's another vacuum hose that starts at a small flat valve strapped to one of the heater hoses that go through the firewall, and ends on the driver's side of the throttle body. Disconnect that. This hose is 1/4" on one side and 3/16" on the other, so be careful with it. If you break this hose (or the other funny one) you can buy adapters and spare hose at most auto parts stores.
18. * There are two long, thin, brass-colored plates that run along each side of the top of the intake manifold, just inside from the fuel rail. These have two phillips head screws each holding them to the intake manifold. Remove the screws and remove the brass plates. I say that like it's easy, but probably it's going to be very hard to break the screws free. Just keep at them...they're tight for a reason.
19. * Remove the 6mm allen head bolts that hold the intake manifold to the engine. There are 10 of them. Six of them are short bolts; there is one per cylinder right near each spark plug. Four of them are longer, and they'r eat the top of the intake manifold directly under where those two brass-colored plates were.
20. * Now screw the brass colored plates back in. This is important because these plates hold the fuel rail on to the manifold, and the fuel rail holds the fuel injectors in place. The rail is also a very nice handle and if it's secured, you'll be able to use it as such.
21. * Pull straight up on he intake manifold; it may take a bit of work to un-stick the gaskets, but keep at it. If it takes too much effort, you've missed something. Don't try to pry it off.
22. * DON'T PULL THE INTAKE MANIFOLD ALL THE WAY OFF YET! You just wanted to free it from the gaskets. If you pull it up about 2 or 3 inches, you'll see a thin, delicate wire that's attached to a sensor on the passenger's side of the intake manifold, near the throttle body. That's the EGR temperature sensor, and if you have a shop manual it probably doesn't mention it. Prop the intake manifold on something, or have an assistant hold in to it, and unscrew the sensor with a 10mm open-ended wrench. Don't worry about twisting the wire, it will untwist when you're done.
23. * NOW pull the manifold off. Hey, that wasn't so hard, was it?
4. Remove the valve covers. They are held in place with six 5mm allen head bolts. Each cover has a rubber gasket that will come off with the cover. Throw it away, you need to replace it.
5. Remove the various parts hanging off the rear of the heads, including the camshaft position sensor (red arrow) and the ATF dipstick (if you have an automatic transmission; violet arrow). If your vehicle was manufactured in early 1992, you have a vacuum pump on the right rear cylinder head; otherwise you have a plate covering a hole there. In either case, remove it.
6. There is a coolant pipe that goes into the back of each head - remove.
7. If you want to remove the camshafts, now is the time: Remove the camshaft bearing caps. There are four of them, and each one has a pair of 13mm nuts on it. Remove the two bearings in the middle first, then gradually loosen the four remaining nuts on the front and rear bearings in a diagonal alternating pattern. Caution! DO NOT interchange camshaft bearing caps! Identify which one goes where and don't forget! Removing the camshafts is not necessary for the procedure; however it is necessary if you want to replace the camshaft oil seals, which I recommend doing.
8. Carefully remove the camshaft, noting which side of the engine it's on. Each camshaft will take two oil seals with it, one in front and the other in back. Note which direction they face and throw them away.
9. Disconnect the two harness connections for each oxygen sensor. I found it convenient to also remove the sensors, but that's up to you.
10. Remove the CO tap tubes (red arrows) and the exhaust manifold heat shields (green arrows).
11. Disconnect the exhaust pipes from the exhaust manifolds. I found that these were the hardest to remove in the entire project. They're baked on and rusted on, and were extremely hard to remove. You will probably strip the nuts and have to replace them. You might, after some cursing and skinning of knuckles, wonder if it would be easier to remove the exhaust manifolds from the heads instead. It wouldn't be - you would have to pry the manifolds about 2 inches away from the heads to release them from the studs holding them in place, which doesn't really work all that well. Keep at it!
12. Disconnect all spark plug wires. Leave the plugs in place.
13. Remove the cylinder head bolts, remove cylinder heads. It's probably worth breaking all eight loose, then going back around and removing them. Then pull off the heads -- this is much harder than it sounds. The heads will be very hard to remove. Beat on them with a rubber mallet; resist the urge to pry them off with a screwdriver lest you damage the surfaces. Keep in mind that there are some passages that extend past the gasket surface, so the heads have to come straight away from the engine block - they won't slide off. Note that some coolant and oil may dribble out of the heads when you pull them off.
14. Throw away the cylinder head bolts. Throw away the old head gaskets. Marvel at this unusual view you have of your engine. Show off to your spouse, friends, neighbors, or whoever you can get to listen. Try not to look worried when they tell you that they won't be impressed until you've put it all back together and the car runs.
15. Heck, take a break. Have lunch or something. You're halfway through! Besides, you'll need your energy for the job to come...
16. Back already? Great. Now it's time to put it all back together. In the immortal words of Robert Bentley, 'Installation is the reverse of removal.' Got it? Good.
17. First make sure that the surfaces on the block and heads that will touch the new gasket are clean. Use a toothbrush or something plastic to clean the surfaces - don't use a screwdriver or wire brush or anything that might scratch the surfaces! Also make sure that stuff doesn't fall into any of the coolant or oil passages on the block.
18. Place the new gaskets on the engine block. They will have markings that indicate which side is up; mind them.
19. Set the heads back on the block. Do this with a minimum of wiggling, but make sure that everything is aligned. In particular make sure that you've aligned the exhaust manifolds with the exhaust pipes, because this will be a lot harder to do once the head is tightened on.
20. Tighten the head bolts. This will happen in three stages, and each stage must go in order. The order is important! Look at the picture!
21. The numbers you see in the picture (1-8) are the order you need to tighten the bolts in. The order is important because if you go in a straight line, the gaskets will deform and not seal properly. Even a slight deformation will be a problem, because of the small amount of space between cylinders. Anyway, in the first stage, tighten the head bolts (in order) just finger tight. Next, tighten them all again (in order) to 60Nm (44 ft lb). Finally, tighten them all once more (in order!) an additional 1/2 turn (180°). You will probably find a breaker bar useful for this last stage. Two 1/4 turns (90°) are OK, but do each bolt at once; don't tighten all eight bolts 1/4 turn and then go back for the second 1/4 turn.
22. At this point, the remainder of the procedure is essentially child's play - you just need to re-install everything you took off. Start with the exhaust manifolds - reconnect them to the exhaust pipes. Tighten the nuts until the springs on the bolt heads have compressed about half as far as they can. This isn't exact, so don't worry.
23. Reinstall the CO tap tubes and oxygen sensors if you removed them. Notes on oxygen sensor installation are here.
24. If you removed the camshafts, reinstall them with new oil seals now. Coat the new seals with fresh oil before installing them. Coat the bearing surfaces with fresh oil before setting the camshafts down. Use your camshaft holding tool to make sure that the camshafts are installed at TDC! Install the bearing caps in the same position and orientation as before. Tighten the nuts to 20Nm (15 ft lbs). If you went hog wild and replaced your hydraulic lifters, note the time - don't attempt to turn the engine until the camshaft has been installed for at least 30 minutes.
25. Reinstall things like the camshaft position sensor, ATF dipstick, and vacuum pump that you removed earlier.
26. Coat your new valve cover gaskets with fresh oil and press them into the valve covers. Apply a small amount of silicone grease to the corners where the camshaft leaves the cylinder heads. Reinstall the oil splash guards (those black plastic things that were sitting on top of the camshaft bearing caps) and then the valve covers. The bolts for the valve covers should only be tightened to about 10Nm (7 ft lbs).
27. Follow the reinstallation steps on the oil check valve replacement procedure.
a. Put the valley pan cover on a flat surface and make sure that it isn't warped before you put it back on the car.
b. When you re-torque the valley pan cover, don't just tighten the screws around in a circle. Cross the pan with every screw. Get them finger tight at first, and then torque them to 10Nm (7ft lbs) with your torque wrench.
c. Remember to counter-twist the wires for the EGR temp sensor before you screw it in, so the wires aren't twisted when you're done.
d. The EGR valve -> intake manifold gasket is more important than it looks. Use the new one, and make sure it's tight!
e. Torque the intake manifold bolts to 20Nm (15ft lbs).
f. Tighten the fuel rail connectors well! Just be careful not to twist anything off. Use two wrenches.
g. Don't forget the ground wires!
h. Once you've put everything back together, and you start the car, it will run like crap for 10-20 seconds while air gets out of the fuel lines. Just grit your teeth and put your foot on the gas pedal until it smoothes out (don't put the pedal to the floor; hold it down just enough to keep the car from stalling). It might still cough every once in a while for a mile or so, but don't worry unless it continues for days.
i. Make sure that the phillips head screws that hold those two brass colored plates down are very tight! Otherwise the injectors will leak fuel onto the engine, and you don't want that.
j. It's a good idea to have an assistant sit in the car and rev the engine for a bit while you look for fuel and vacuum leaks. Do this before you take your test drive!
28. Reinstall spark plug wires if you haven't done so already.
29. Follow the reinstallation steps on the timing belt replacement procedure. Turn the engine by hand at least two full revolutions once the timing belt is installed to make sure that the valves aren't striking the pistons. Make sure that you have camshaft and crankshaft TDC lined up properly!
a. The new thermostat goes in just like the old one was -- note that there's a little vent hole on the thermostat, which should go on the top. Don't forget the O-ring, which is attached to the metal duct.
b. Put the metal duct back on, and re-connect the radiator hose if you disconnected it. Note that the radiator hose has an arrow printed on it which corresponds to an arrow on the metal duct.
c. Align the water pump gasket with the water pump using a couple of the screws, and position the water pump on the engine block. Screw all of the bolts in finger tight. Make sure that the gasket is not sticking out too far anywhere.
d. Set your torque wrench to 10Nm (7 ft lbs). If it doesn't go that low, just keep in mind that it's not much torque! As you're screwing in the pump, don't tighten the bolts in order! Do one bolt, then skip 4, then skip 4 again, etc, until you've gotten them all -- otherwise the gasket will become deformed.
e. If you got a new timing belt tensioner, now's the time to put it on.
f. Loosely thread the timing belt over the camshaft sprockets and under the water pump.
g. Re-install the camshaft holding tool.
h. Put the teeth of the belt into the camshaft sprockets; then thread it around the idler pulley, then the crankshaft sprocket, and then the tensioner (last). Adjust the tensioner until the belt has the proper tension, then tighten it.
i. Tighten the camshaft bolts to 30Nm (22ft lbs) plus 1/2 turn.
30. That's it! Make sure that you've refilled any fluids that you emptied (notably coolant and oil), reconnected any connectors that you disconnected, and reconnected any vacuum hoses that you removed.
|100, a4, audi, gasket, hard, head, leak, mazda, miata, procedures, replace, replacement, should, step, tt|
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