Special maintenance procedures can prevent premature head gasket failures. Use the lowest operating temperature thermo-fan switch that you can get by with for your climate and use Mercedes antifreeze. See below for pricing on the thermo-fan switch and the Mercedes antifreeze. Incorporate as many of them as apply into your car when replacing a head gasket. We recommend using only the factory head sets or those made by Elring (the factory supplier). The head gasket has been updated numerous times and the factory unit or the one from Elring will incorporate all the changes, others may not. The changes are substantial, eliminating a lot of the dead space holes in the gasket, giving less areas for the deposition of silicates and aluminum salts that lead to the splitting and demise of the gasket.
|THIS IS A CRITICAL REPAIR. ERRORS HERE CAN CAUSE DAMAGE TO THE ENGINE. IF YOU DO NOT HAVE THE PROPER TOOLS OR MECHANICAL KNOWLEDGE, THEN HAVE SOMEONE QUALIFIED TO DO THE JOB.|
1-To flush the cooling system, find a suitable pan to catch the old coolant. Drain it first from the radiator drain. Be careful if the petcock seems tight not to damage the radiator. On 900s, the drain is on the right lower front of the radiator. Early ones have a 17 mm petcock with a 22 mm support hex.
2 - Remove the AIC valve and the thermostat as well.
3 - The head is held with a special bolts requiring a socket, a external torx , E-16. you will need this before starting. If you can't find one, don't start the job. Saab has them under part number 30 13 992.
4 - Remove all the belts. Remove the ac idler pulley and the two upper bolts for the power steering. Remove the two 6 mm Allens holding the ac compressor to the head. Push the alternator all the way to the left against the fender well and remove the 12 mm bolt in the bottom of the compressor bracket. On newer cars, the bracket is slotted and you just need to loosen the bottom bolt and slide the compressor up and out. Do not remove the refrigerant lines from the compressor, you can just carefully relocate it to the right, out of the way on the evaporator box. Now is a good time to tighten the hose clamps on the hoses coming off the back of the water pump and inspect their condition.
5 - On Non turbo cars, remove the rubber bellows connecting the air mass meter to the throttle plate. On turbo cars, remove all the intake tubing. Take care to cover the inlet to the throttle plate, the turbo and the intercooler to prevent anything from falling into them. Use shop rags, or duct tape to make temporary plugs. Don't forget to remove them during reassembly. Now is a good time to clean around the throttle plate.
6 - Remove the electrical connections to the air mass meter, the throttle position sensor, the knock detector, the injectors and the NTSC sensor. Remove the two 10 mm bolts holding the ground wires to the lifting lugs. Note how these grounds are separated. They must go back the same way they came off, separated on the TWO bolts. These wires/connectors are all in a harness that runs from the right side of the car across the engine. Unplug anything in this harness so you can swing the whole harness back to the right and out of the way. Cut any tie wraps securing the harness, note their position for reassembly replacement.
7 - Remove the return line from the fuel pressure regulator. It is held on with a clamp you squeeze to release. We replace this clamp with a screw type clamp on reassembly for security. If this line is getting old, replace it before reassembling the engine. Remove the regulator by loosening the 24 mm nut on its bottom. Remove the vacuum line going to it. Remove the two 12 mm bolts holding the regulator's bracket to the head. Then remove the intake bolts, 12 mm. Note the locations of the longer bolts, in the lifting lug and in the heater coolant pipe bracket. Remove the intake bellows to the throttle housing.
8 - There is a 13 mm nut on the bottom of the intake, at the throttle housing that holds a support bracket for the intake. Loosening the nut will allow the intake to move enough to take off the head. When the intake is free, use a Bungee cord to hold it up and out of the way of the head. Remove the 90 degree bypass hose off the rear of the head (front of engine compartment). The thermostat and its housing should have been removed when you flushed the system. On water cooled turbo cars you have a couple of hoses to remove on it including the oil lines.
9 - Then remove the valve cover gasket. You will need to remove the spark plug cover by removing either the two or four screws/bolts holding it on. They are either Phillips screws or T30 machine screws, depending on the year. Remove the plug wires from the plugs and the distributor cap from the distributor. You can just leave the wires on the cap except for the coil wire. There is a ground wire running to the side of the distributor from the capacitor on the coil, loosen the screw holding it to the distributor and remove it. Retighten the screw to prevent the loss of the clip to hold the distributor cap on. There are 16 12 mm bolts holding the valve cover on. Remove them and lift off the valve cover.
10- On early heads, there are overhead oil tubes supplying the cam bearings with oil. We recommend replacing the plastic pieces here with new ones while the cover is off, after the head is reinstalled. Be sure and remove these tubes before sending the head to a machine shop for resurfacing and checking. Also make sure the guide for the timing chain in the top of the valve cover is not loose enough to move around. If it is, tighten it by bending the tabs on it down with a little tap from a hammer and a punch.
11 -We usually remove the exhaust manifold with the head. You have fewer bolts/nuts to undo to drop the pipe from the manifold and the manifold is easily removed to replace the exhaust gasket with the head off the car. If you have a turbo, you can either leave it on the manifold, or leave it in the car. Leaving it in the car reduces the weight you have to lift and maneuver around, but also makes sitting the head back on a harder job. I take it with the head and get someone to assist me with the lifting, not that it is really all that heavy, but you have to be careful when moving the head around not to damage the new gasket or the timing chain guides. To take it with the head, remove the two lower bolts securing it to its support bracket and remove its oil supply and return tubes. I go ahead and remove the two lower bolts holding the bracket to the transmission to give me more room to move the head around and easier access to the oil return tube. Now would be a good time to check the turbo oil supply line for coking (coking a buildup of oil from heating and cooling of the oil. Almost like layers on a cake). Clean it if it is clogged. It will require complete removal of the line to clean it properly. If you cannot get it clean then REPLACE IT to prevent premature Turbo failure. Use new seals on the banjo bolt holding it to the block if it is disturbed. Also get an O-ring for the lower return tube, Click here for O-ring Pricing! it will come out of the block either when you remove the turbo or when you go back. You will also need new Header Pipe to exhaust manifold gaskets if your car is non turbo.
12 - On the right side of the head, there is a support bracket to the head from the motor mount. It is held to the head with two 13 mm bolts with spacers on them. Keep up with the spacers. A jack placed under the engine at the differential of the transmission will support the engine once you remove these bolts and it can be used for reassembly to ease in the alignment of these bolts on reassembly. I find it easier on cars with hydraulic mounts to loosen the two 17 mm nuts and the 19 mm nut to align the bracket with the use of the jack. Once the bracket is loose from the head, the weight of an unsupported engine can bend the rest of the mount brackets here and give you problems with alignment. Jack up the engine/transmission from below to support it and avoid later problems on reassembly.
13 - Now is the time to remove the timing chain. Set the engine on #1 cylinder by aligning the timing mark on the flywheel with the line on the black plastic clutch/transmission cover at 0 degrees. Look at the cams, they have a pointer cast into their first bearing caps and a mark on the raised edge of the cam where it meets the gear. The mark should align pretty close to the pointer on the cam bearing, but it can be off a bit. Instead of using these marks to set the engine in time, we use the marks on the cam gears/sprockets. When correctly aligned, they are perpendicular to the head, at 12 o'clock. Using these marks to time the cams is less error prone than using the marks on the cams themselves. You can use the starter to turn the engine over and get close to the timing marks. You can rig yourself a switch to do this by going straight to the battery positive terminal with one wire and to the small wire on the starter with another. By briefly touching the wires, the engine will turn over. I use a flat screw driver on the teeth of the flywheel to do the final positioning of the timing marks. Do not use the cams to turn the engine, you can break them or the chain doing so. Once you have all three marks aligned, the crank with its flywheel mark, and the cams with their gear marks, you can remove the timing chain. At this point, to avoid any possible inadvertent key turning, disconnect the negative battery cable to prevent accidental starter engagement. You need to break the 14 mm bolts holding the cam gears to the cams before loosening the timing chain tensioner. Use a 18 or 19 mm (depending on year) wrench on the bosses made onto the cams to hold them still while you break loose the 14 mms. If the engine moves out of time a bit, you can turn it back to align the marks. Do not remove the 14 mm yet. You have to remove the tensioner first. To do so, first determine which tensioner you have. If it is a flat cadmium colored 27 mm bolt, you have the old design. You need to update this part. get part number 7585086 and a new seal for it, part number 7508690. The tensioner lives under where the ac compressor mounts, in the front of the head (rear of engine compartment). To remove it, just turn out the tensioner with a socket. They can be hard to break loose. When you get the tensioner out, you should have the top plug, a spring and a bottom plunger. If the tensioner was doing what it should, the spring and plunger may stay in the bore. A magnet will fish them out. Get them out before going any further as they could fall into the motor. If the tensioner you have is black, with a 12 mm bolt on top of a 27 mm body, you have the updated tensioner and there is no need to replace it with a new one, but use a new seal for it. To remove it, remove the 12 mm bolt, get the spring and plastic plunger out of the hole. Then remove the 27 mm tensioner body. When you get the main body out, measure the length the plunger is extended. If it is more than 11 mm, Saab says to replace the timing chain because it is stretched. See the section on replacing the timing chain for more info. If you pull out the tensioner without removing the 12 mm first, the measurement of the extension will have no meaning, the spring will have fully extended the tensioner. You have to release and contract the tensioner before you reinstall it. Look at the end of it and find the ratcheting mechanism. Pushing on the tab will allow you to push the extension back into the body of the tensioner. You will install the contracted body first then add the plastic plunger, spring and plug after the body is tightened down. Installing a fully extended tensioner can break either the tensioner, guide, or the chain. Use a new seal with the tensioner on reassembly. Click here for pricing on the Saab 900 Timing Chain Tensioner! Now remove the 14 mm bolts you loosened previously holding the cam gears on. Pull off the intake cam sprocket first (one toward the left side of the car, uppermost) and remove it from the chain. Then do the same for the exhaust sprocket. Let the chain lay out of the head at the bottom right side.
14 - There are two bolts coming up from the front of the engine, holding the head to the timing cover. They are either 12 or 13 mm depending on the year. Most are 12 mm. The heads of these two bolts face the ground. Remove these bolts. I find a short offset wrench works best. Now its time to remove the head bolts. Be sure the head and engine is cool before removing them. It is best to remove them in the reverse order of the installation order, starting at the distributor end of the head, remove the bolts in a counterclockwise way, starting at the bottom bolt on the distributor end and ending at the top center bolt. Now you an jack up the engine a little with the jack you put under the transmission to get enough clearance to easily remove the head from the front of the engine. You have to drop the front of the head down slightly to clear the timing chain guide. The lower guide is fixed and doesn't move, the upper one that the tensioner pushes to tighten the chain will move in far enough to clear the head. Just move the timing chain so the guide can swing down. Lift off the head.
15 - Carefully clean the block and head surfaces. Be very careful not to remove metal from either surface. Also be aware that if you use grinding pads on a die grinder or drill to clean the block and head, that grit will be generated and may cause engine damage if it gets into the engine. Cleanliness is critical. Although it takes a good deal more time use a razor blade first to remove the biggest parts of the gasket. A few cans of brake cleaner will be needed to clean up the block, pistons and head bolt holes. Make sure you blow out the head bolt holes before reassembly, leaving oil, grit, gasket material in them at the least can cause the bolts to seize or not fully seat and at the worst may crack the block or strip the threads. Make sure you keep up with the two alignment pins that fit around two head bolt holes. They will either come out in the head or stay in the block. Best thing to do with them is to remove them, clean them, and put them back in the block just before putting on the new gasket. You can hold the timing chain up by hand and turn the engine over BY HAND to bring up the other two pistons to clean the carbon from them. Make sure you clean out the cylinders of any grit/trash. Make sure you keep the chain as tight as possible while turning the engine so it won't get tangled around the crank. You might want to have an assistant insert a big screwdriver through the chain, so it will turn around the screwdriver as if the screwdriver were the cam gears, while you turn the engine by hand using the flywheel. Insert the screwdriver in the loop of the chain, pull up on it to tighten the chain while turning the engine to keep the slack out of the chain and it possibly falling off the bottom gear. This step is not necessary, but I like to have nice shiny pistons and clean cylinder walls.
16 - After you get the block surface clean, it doesn't hurt to make sure its surface is flat with a straightedge. Although I have yet to see a 2.0L engine have a problem here, it is becoming a problem on 2.1L engines. Pay special attention to any areas between cooling passages and the cylinder walls. Drain the engine oil. I suggest leaving a pan under the drain hole and the drain out until you finish the repair. Washing out the engine with a couple of quarts of oil is not a bad idea.
17 - Now move on to the head. Clean its surface as you did the block. If there are pits in the areas of the head above the coolant passages in the block, we fill them with JB Weld. It is a real good idea to take the head to a machine shop and have it resurfaced if this is the case. They can check the head for warp age and cracks as well as give it a good cleaning. If you do a preliminary cleaning, and epoxy the pits and allow the epoxy time to dry, the machining will go better. Most of the time, the pits are too deep to completely remove with resurfacing. The minimum head thickness, measured from the top to the bottom must not be less than .4 mm less than the new head thickness of 140.5 +/- .1 mm. We have used the epoxy in the pits fix for years with no problems, saving a lot of otherwise ruined/questionable heads. You can have the machine shop recut the valve seats, but do not have the valves cut. Valve seat angles are in the table below. If there is a valve problem, use only factory valves. They are stellite coated and sodium filled, critical to their life in the extreme conditions they face. Improper valves will fail very rapidly, especially in a turbo.
18 - If the seats are cut, the valve heights must be adjusted. This is done by machining away the tops of the valve stems to get the correct height. Since there is a limit to how much the lifters can adjust, this height is critical. Saab makes a special tool to measure it, 83 93 753. They have a special stellite coating to prevent them from burning and anything more than a light lapping will remove the coating. It is also a good idea to have the valve stem seals replaced. They come with the head gasket sets we get. The guides are checked while the valves are out. Raise the valve 3 mm off its seat to measure guide clearance. The spec is .5 mm. Move the valve side to side and use a dial indicator to measure the movement. Replace any valve guides with more clearance than this.
19 - Before taking the head to the machine shop, I advise you to strip it down. Remove the temp sending unit, the spark plugs if not already out, the distributor, noting its orientation, the exhaust manifold, the cams and the lifters. You can separate the turbo from the exhaust manifold to replace the metal gasket between them. When I do this, I wait to reinstall the turbo until the head is back on the engine. Be careful when removing the exhaust manifold, the nuts used are locking nuts and they make strip a stud or break a stud. Liberal use of WD-40 and retightening a stiff nut instead of forcing it off will usually get them off with no problems. I also recommend replacing the exhaust nuts. Keep up with all the washers and spacers and note the orientation of the metal side of the exhaust gasket when you remove it. Install the new one the same way, with the metal side facing the exhaust and the softer side facing the head. The cam bearing caps are numbered and have an arrow pointing to the cam gears. Make a note as to where #1 is and keep them in order. They are machined to only fit in one spot. Swapping then can seize the cam. Note that you have two different bolts holding the cam bearings down, the black ones go to the interior of the caps, allowing oil to pass through them. Before pulling the lifters from their bores, wipe off their tops and number them with a magic marker. They need to stay in the same place they come from due to established wear patterns. Swapping them may cause wear and loose metal production. Keep them in a clean place so they won't get covered in grit. A magnet, or careful use of pliers will pull them from their bores. For the cap for the distributor, the tamperproof 40 torx bolts can be a pain to get out. I give them a good smack to break them loose and use a impact driver to get them out. Sometimes, I break bits getting them out. If you have much trouble with them, leave them for the machine shop to deal with, just make sure you get them back when you pick up the head, along with the two alignment pins that fit under them. Once you get the head back, make sure there is no metal from the resurfacing in it. The metal can get anywhere there is a hole. Blow it out good with compressed air, or use brake clean liberally to insure there is no metal floating around in it.
20 - I recommend using an engine assembly lube to put the cams and lifters back in the head. Make sure everything is as clean as possible, and put a small amount of the lube around each lifter. Keep the lifters in their original holes. Next, make sure the cams and the bearing cap are clean and grit free. Use the assembly lube on them at the lobes and the journals. Before torquing the bearing caps, raise the bottom of the head slightly above the table so any opening valves will not hit it. A block of wood on each end works well if you do not have head stands. Make sure you don't mix up the cams. The exhaust cam will have a slot in its end to drive the distributor. Place the cams in the bearings and align them as close as possible (they will move when you tighten the caps, so just be close right now) with the timing marks on them and the first caps. Make sure you put the black cam bolts in the spark plug side of the bearing caps. The front caps have two cadmium colored bolts, so keep all the bolts in the right places. Starting in the center of the cam, tighten the bearing caps gradually until they are all hand tight. Then use a torque wrench to set the final torque at 11-15 ft lbs. Go back through and recheck all the caps torque when you get through them once. Turn the cams back so their marks line up, its ok if they don't stay exactly on right now.
21- Reinstall the temperature sending unit, the distributor and the exhaust manifold. If you have the distributor retaining bearing shell off, a small bit of Loctite 518 sealer under its ends will prevent leaks here. Use a new o ring, part number 9176470 Click here for Saab O-ring pricing!, on the distributor. Torque the exhaust manifold nuts to 18-20 ft lbs.
Clean the intake manifold of any old gasket material as you did the block and head surfaces.
22 - The head bolts used on the 16V heads are torque to yield bolts which means they will stretch somewhat to achieve the proper tension on the head. They can stretch too much to use. Make sure none of them is any longer than the rest. If some are stretched, you need to replace them, they may snap when you retorque them. It is very rare for Saab head bolts to not be reusable. Make sure the bolts threads and shafts are clean. Use WD-40 to lubricate them before reuse.
23 - First recheck that the crank is on top dead center by making sure the #1 piston is at the top of its bore and that the mark on the black plastic transmission cover points at 0 degrees. On the head, make sure the cams are close to aligning with their marks and the first bearing caps pointers. Not doing this, and tightening the head bolts with the cams out of time, can bend the valves. Make sure the head bolt holes are clean and that nothing is laying on top of a piston. Insert and seat the two alignment pins in their appropriate holes in the block. Apply a small amount of 518 to the seams where the front and rear engine covers meet the block. Lay the head gasket on the block, making certain it is oriented correctly. An old head bolt with the head cut off and a slot cut in the top of it for a flat screwdriver makes a good tool to carefully put the head back on with and to hold the gasket in place. Insert the bolt into the bolt hole near the rear of the engine (front of car) that the upper alignment pin goes in. Screw it in lightly, but at least a couple of turns. A wooden dowel inserted in the hole may suffice, but the old head bolt is sturdy and can support the weight of the head should you need it to.
24 - Carefully start the head back down by starting it over the cut off head bolt in the appropriate hole. You will need to have the engine raised up as you did for disassembly. Swing the bottom front downward, swiveling on the cut off bolt, to clear the bottom chain guide with the front of the head. Make sure the chain stays in the groove of the lower guide and that it does not fall into the timing cover and become lodged. It is best to reach through the head and pull the chain up, but you can't pull it tight enough to push the upper guide out so it interferes with setting the head down. Be very careful not to damage the guides when lowering the head and that the chain doesn't fold or become caught in a bind. Be certain the chain is free before torquing the head bolts. Be extremely careful not to damage the gasket or move it off the alignment pins. Start the head bolts and tighten them enough by hand to hold the head down. Then remove the cut off head bolt and insert the proper bolt in that hole. Starting in the center upper hole and going out clockwise from there, torque the bolts in three stages. First set them all to 45 ft lbs. Then go back through and tighten them to 65 ft lbs. For the third and final stage, you do not need the torque wrench. Give each bolt an additional 90 degree turn to get the torque to yield spec and stretch the bolts. I use yellow chalk to keep track of which bolts I have already tightened to avoid missing one or doing one twice. This final 90 degree turn will get pretty hard, you may want a ratchet or pull bar with a long handle. With the latest head gasket design from either Elring or Saab, no further torquing or warm up and retorque are needed. If you use some other head gasket, follow the instructions that come with it.
25 - To set the engine in time, again recheck the crank timing via the pointer and degree wheel on the flywheel. It should point exactly at 0. Pull the chain up tight from the bottom (exhaust) side of the engine and start the cam gear for the exhaust cam in the chain. Be careful not to pull the chain so hard as to turn the crank, keep a constant check on the flywheel marks. I find it easier to turn the exhaust cam back counterclockwise just a hair off its mark. Then install the exhaust cam gear on the cam, making sure its notch fits in the groove in the cam. Make sure the line on the cam gear is perpendicular to the head. If you turned the cam counterclockwise, bring it back so that the line on the gear is perpendicular to the head, making sure doing so does not move the crankshaft. Recheck the flywheel marks. This little bit of movement makes it easier to align the cam and gear with each other and still keep a tight chain. You just have to make sure the crank doesn't move off 0 when doing it. Start the 14 mm bolt in the exhaust cam holding the gear on but do not tighten it yet. Pull the chain over the intake cam gear, getting the line on the gear close to perpendicular with the head. I also turn the intake a bit counterclockwise to ease in the mating of cam to gear. Pull the cam back to its marks after slipping the gear onto it. When the gear goes on the cam, make sure all the marks line up still, the crank with the flywheel mark and pointer and that each line on the cam gears is perpendicular to the head. You can double check the cams by looking at the mark on them and the pointer on the first bearing cap. They should be close, but often aren't dead on. Using these marks alone to time the engine sometimes leads to a cam being a tooth off and a rough idle will result. I have yet failed to get an engine in time correctly by using the marks on the gears perpendicular to the head. The small radius at the cam leaves too much room for error where the line on the bigger diameter gear is both easier to see and has less room for error. If you have a lot of trouble getting a cam gear on the cam or seem to have too short a chain, double check the timing marks and insure that the chain isn't folded or in a bind in its guides. Rocking the crank back and forth via a screwdriver on the flywheel teeth will usually free up a bound or folded chain. Just be extremely careful not to force the engine to turn, you may be bending a valve. If you get something you can't get loose, it is cheaper to remove the head to free the chain than to replace bent valves.
26 - When all three marks align, and you have no slack in between the cam gears while holding the intake gear tight against the chain on its mark, you can put the tensioner in. Do not attempt turning the engine over until the tensioner is fully installed. Use a new seal ring and the later design tensioner. Make sure the plunger on the tensioner is fully retracted, no teeth showing on it, and install the body of it in the head. Torque the body to 45-50 ft lbs. Then install the plastic plunger into the body followed by the spring and plug. Check the O-ring on the plug and replace it if it is torn or hardened. As you screw in the plug, the spring and plunger will adjust the tensioner to take out the slack in the chain. After it is in and tightened to a torque of 11-15 ft lbs, gently turn the intake cam, or apply tension to it with the 18 or 19 mm wrench on its boss until the slack between the gears is gone. You might hear the tensioner ratchet out another tooth or so. Torque the cam gear bolts, the 14 mm holding the gears to the cams, to 45-50 ft lbs. A drop of blue Loctite Thread Locker on each is good insurance they will stay put. A wrench on the bosses of the cams will provide a holding mechanism against your torque wrench. Now, before going any farther, turn the flywheel via a screwdriver in its teeth in the direction of engine rotation (counter clockwise) until the timing marks point at 30 degrees on the flywheel. Both cams should have moved somewhat with the flywheel. Come back the other way to 0 with the flywheel and recheck the timing marks. If they all align, turn the engine over counterclockwise until the marks come back up. This will require turning the flywheel two revolutions. If at any point you meet with excessive resistance, stop and go the other way and recheck the timing marks. After the marks come back up, recheck all three and make sure they align at 0 degrees on the flywheel and that the cam gear lines are perpendicular to the head/bearing caps. When you get the engine in time, then is the time to reinstall properly gapped spark plugs to prevent dropping anything into the cylinders. A bit of anti seize compound on the plug threads makes next time easier. Install the distributor. Note that with the ignition rotor installed on the shaft, there is a notch cut into the distributor body on the edge the cap fits to, under the plastic cover. The rotor should point at this notch. The distributor's drive dogs are off set and it will only fit into the exhaust cam one way. Make sure its orientation is close to the way it was when you removed it. A little grease on its O-ring will make it easy to reinstall. Don't tighten it all the way down, just tight enough to still allow movement if you need to turn it a bit to adjust the ignition timing.
27 - If you have an early head with overhead oilers, now is the time to replace the plastic pieces with the o rings that supply the cam bearing/journals with oil. The o rings harden and allow oil to leak past them. This causes the lifter noise that arises from low oil pressure reaching them or air entering them. New o rings fit so tight, it may require gentle hammer taps to fully seat them. Just be careful not to break them. It is also a good idea to make sure the oil tubes are clear and clean. Crab clean and a coat hanger wire make cleaning them easy. After these are in place, refit the valve cover with a new gasket set. Spray gasket adhesive works real well to temporarily hold the gasket in the grooves in the valve cover. Note that there are two sizes of grooves between years of 16V engines, one smaller in diameter than the other. If the gasket doesn't fit tight in the grooves, or is too big for them, you have the wrong gasket for your car. They fit ALMOST tight enough to hold themselves in the grooves, but are loose enough to fall out when you invert the valve cover. The spray adhesive is enough to keep them in place for installation. Do NOT use RTV silicon sealer to hold the gasket in place. Silicon will push out from under the gasket when you torque it and will eventually flake off and may block oil passages and starve something for oil. Of the few Saab engines I have seen with bottom end problems, most were caused by blocked oil pick tubes full of flaked off silicon. You can use a sparing amount of silicon on the plug seals (half moons) of the gasket and over the hump of the distributor, but we have been using Loctite 518 here, it is much safer if any excess oozes out. The 518 is anaerobic only dries between parts, If there is excess, it will not block any oil passages. Torque the valve cover bolts to 14-20 ft lbs.
28 - Now move to the intake. A bit of 518 around the coolant passages on the gasket will hold it to the head while you fit the intake. Start all the bolts first before tightening any. When they are all started, a telescoping magnet makes starting some of them easier, torque them to 16-20 ft lbs. Tighten the nut under the bottom of the throttle at the supporting bracket. Reinstall the fuel pressure regulator bracket, regulator, and the return fuel line. Check and replace any questionable vacuum lines. Cementing any weak grommets (or replacing them if very bad) to vacuum ports should be done on reassembly. Clear the PCV nipple on turbo's, make sure the check valve is installed properly and routed so that it allows suction out of the valve cover but no blowing into the valve cover via the small vacuum line going to the PCV nipple. Moving it farther from the PCV nipple and closer to the intake will keep a lot of the oil and heat off of it. The part number for the check valve is 75 21 313.
29 - Reattach the wiring harness. Check all the pins and clean them with contact cleaner if any are corroded. RTV silicon will seal up any broken boots. Attend to any bare insulation problems. Most of the connectors are marked where they go, the harness really has them fall in place. Careful notes on disassembly makes this step go much easier. Use tie wraps where the factory did to prevent the harness from rubbing or getting into harm's way.
30 - Reinstall the turbo (if applicable), using new gaskets between it and the exhaust manifold, on its oil supply and return tubes. Use a new o ring on the return line where it enters the block, part number 75 02 263. I find it easier to start the bolts in the turbo's bracket at the tranny, running them just before snug so some movement is allowed. Start the bolts and nuts holding the turbo to the exhaust manifold, but leave them loose until the oil return line is inserted into the block and started on the turbo. Then tighten all the bolts. On non turbo's, use new gaskets between the exhaust manifold and down pipe, part number 46 24 383, two Needed. We recommend using new locking nuts on all the exhaust connections. Copper ones with the locking ends work best if you can find them. If any studs were stripped or broken, take care of them before going back together.
31- Reinstall all the intake tubes/bellows. Check all the hose clamps, make sure they are tight. On turbo's, pay attention to the tube that passes under the overheat switch in the upper radiator hose. Sometimes the clamps will rub a hole in the tube. Make sure the clamps can't rub the tube. Check the turbo bypass valve click here for Saab 900 bypass valve pricing! in the tube from the air mass meter to the turbo. It should hold vacuum in its small line. If plastic clamps are holding it on, replace them with metal hose clamps, the plastic can become brittle and break and allow the turbo pressure to push the valve out of the tubing and stall the car. Reinstall the AIC valve and its hoses. A cleaning of its shutter wheel with a Q-Tip and crab clean will keep the deposits from burning out the electrical motor. A shot of WD-40 on the wheel will prevent it from binding.
32 - Reinstall the ac compressor. Reinstall the belts. You might want to replace them if they are over three years old or show cracking or oil saturation. At this time, replace the upper radiator hoses and the bypass hose at the rear of the head if they are over three years old. Replace any tune up parts that may be due, air filter, fuel filter, cap, rotor, or wires. These hoses carry the hottest coolant in the engine and fail from the inside out before any other hose. Replace the thermostat with part number 88 17 538. Tighten the oil drain plug after replacing its seal with a new one. If the engine mixed its coolant with the oil, you might consider pouring a quart of oil through the engine to help wash out as much of the mix as possible. Change the oil filter and refill with oil. Close the radiator drain and reinstall any removed coolant hoses. Make sure the heater temp selector is still on hot. Refill with a 50/50 coolant water mix. Open the bleeder port on top of the thermostat, two 7/16 or 11 mm wrenches are needed. Fill the reservoir until it reaches the max line. Air will escape from the bleeder port. When a steady stream of water comes out of the bleeder, close it off and top up the coolant reservoir. Reattach the negative battery cable. Reinstall the plug wires and reattach the capacitor wire from the coil to the distributor. Leave the coil wire disconnected, and jumper it to ground to disable the ignition. Crank the engine over until the oil light goes out. Let the starter rest a few minutes and crank it over a bit more. Connect your coil wire to the distributor and she should start up. If not, turn the distributor a bit to get it to fire. All the cleaning and cleaners may make it a bit hard to start initially. The oil may have gotten washed off the rings and cylinder walls and it may take a few revolutions for the compression to come to these cylinders. Be patient. You also have to wait for the fuel rail to pressurize and bleed off any air. when the engine starts, let it idle for a few minutes. It is normal for the lifters to clatter for a while after this repair. While they are clattering, they aren't fully opening the valves, so a rough idle may occur. Let the engine idle until it comes to normal operating temperature, when the fans cycle. Be watchful for leaks. Top up the cooling system as needed as the engine warms up. Turn the car off, let it set 5 minutes, rebleed the cooling system, and recheck the oil level. If the oil shows signs of coolant still in it from the mixing during the failure of the gasket, you may want to change it and the filter at this point again. Start it back up and set the ignition timing at idle with a timing light. On non turbo's the setting is 14 degrees before top dead center (BTDC) and for turbo's it is 16 degrees BTDC. Tighten the distributor hold down all the way snug so that you can't turn the distributor. Give the car a gentle test drive. Recheck all the fluids and for leaks. If the lifters seem to take a while to quiet down, it is not abnormal. It takes a while for the air to work its way out of the system. it is not uncommon for them to get quiet and then noisy for a few restarts after cooling off for a few days after the repair is finished. But, the noise should quickly diminish from its initial levels and you should be able to discern that only one or two lifters are persistent in continuing to click. If the noise gets louder, stop the engine, remove the valve cover and make sure the cams are getting oil.
The only additional work to be done after a head gasket replacement is an oil and filter change after 500 miles to insure no debris from the repair is circulating in the oil and a recheck of the ignition timing just to be sure. A close vigilance over the engine for the first week is advisable. The newest gaskets do NOT require retorque.
Check a few other items while doing this job and you may save having to remove some parts 2 times. You might want to consider replacing the timing chain if the tensioner showed more than 11 mm extension on its plunger or if the cam gears and chain show wear. If the guides and gears look ok, it is fine to 'roll in' a new chain Click here for the Saab 900 timing chain tools!. Saab sells a kit with master links to do this job. I wait until the head is back down to roll in the new chain. You might also consider the condition of the Saab Alternator bushings and Saab Water pump while the head is off as well as the Saab 900 front oil seal and oil pump o ring.