REPAIRING MANIFOLD STUDS - read this ALL before starting 1991 Nissan Maxima SE I am not responsible for any damage to your car. Here we go. It was time consuming for me, I worked on it after work for several days (after 4-12 shift). If I had to do it again. It would not take that long. I do recommend that you do both sides while you are at it, but it is totally up to you. I followed instructions that can be found on 4dsc.com for the front, with some changes. I put my car up on ramps that I use to change my oil. It would be nice if you had these. Remove battery cables. Remove splash guards under the car. Remove the hose from the air cleaner to elbow leading to throttle body. Remove the front spark plug wires. Remove elbow to throttle body. (Clean throttle body while it is apart). Take throttle body off slowly trying not to rip gasket. Mine did not rip. I drained my radiator but that was my preference because I removed my radiator for more room. Your call. when you remove transmission cooling lines to radiator get a container to capture fluid. ( probably a quart or so). Remove fan shroud . the plugs are on your right hand side—are two of them, just make sure you know which is top and which is bottom. Now remove radiator top and bottom hoses and remove radiator. This opens up the front nicely. Now loosen the belt on a/c compressor and pop belt off. According to 4dsc, they want you to remove the alternator too. You don't have to. There are 4 bolts holding on the a/c compressor. Once you have it off, just move it up to the front left corner, being careful of hose stretching and tie it off with a bungee cord. Now you should have a great look at the front manifold. Spray the nuts with pb blaster or other penetrating oil (WD-40 is NOT penetrating oil). Soak them good and let it sit awhile. Next you need to remove the egr piping from the front manifold. Soak with pb blaster. Don't be afraid to tap nut with hammer to shock it. Get that puppy off from the front y- pipe. You may be able to move this away enough, if not loose up nut at egr valve too. Next, there are two bolts holding the oil dip stick. Remove them and I was able to just slide it out of the way. Now you have to remove the y-pipe from the manifold. I use PB blaster, It is the tits. Spray those bolts down good, front and back, soaking the threads. I let it sit for a day after I sprayed them. I also used a small wire brush to get the rust off the threads. I also heated them up using MAP gas (instead of propane) prior attempting to remove. If you don't know what MAP gas is, you can buy a cylinder of it where you get propane at. Just be patient removing bolts. If it gets tight coming off. Turn them back on a ways, spray more PB on it and try removing again. They will come out. I live in PA and salt is an issue and mine came off. If I remember right, there is a bracket on the bottom of the y- pipe connected to the frame or cross member you have to remove. Look around on the y- pipe and it will be found. Once you remove the y-pipe from the front and back, you will have to break the bolts back at the Catalytic converter. I had to use a small grinder. (I have a air die grinder) and cut the bolts off and removed the y-pipe out of the way. PRIOR TO ATTEMPTING TO REMOVE NUTS FROM MANIFOLD. Make sure you used plenty of pb blaster on the nut. Now the secret. Use propane or MAP gas and heat up one nut at a time until it gets cherry red. Then just put you socket on it and start to remove. Again, if it gets tight, tighten it back up and try removing again. Be patient, going back and forth and you won't break any off. After all bolts are off, just pull the manifold off. NOW ANOTHER SECRET. Spray pb blaster on the studs at the head and let it sit. Also, tap the end of the studs with hammer, not real hard but with some force. If you have a stud remover, you will need a metric size, mine came right out. But I tapped and sprayed them for about 3 days in a row prior to removing them. Don't force them, if they are tight. Heat the head around the stud, not directly on the stud and this will expand the hole. If you heat the stud, it will expand the stud and make it tougher to remove. But if you tap them and spray them liberally, they will come off. If you don't have access to a stud remover, I heard guys put two nuts together and back them out. Or you can use vice grips to remove them. My car is a 91 and mine came right out using the procedure I just mention. NOW FOR THE BACK. TOUGH. NOT REALLY, TAKE YOUR TIME AND YOU WILL SAVE YOURSELF A PILE OF $$$$$. Hopefully, you have a set of car ramps. If not, try to keep you blocks as close to the wheels as you can. If you don't have car ramps, go buy some because you will be saving money and is a good investment. It makes it safer too. Get the PB back out and spray your motor mount bolts on the cross member up good. You can spray all the bolts prior to all the previous steps to get a head start. Use your wire brush to clean the threads up too. You need to remove the cross member. Your cross member attaches to your front and back motor mounts. Once under the car, you will see this easily. On the motor mount bolts, I heated them up prior to attempting to remove. These nuts were the easiest to remove. Just break the front and back nuts up BUT DON'T REMOVE YET. Once they are free you are almost home. Now you need to get a jack of some kind and support the engine. I used a board on top of my jack and put the board up against the oil pan and supported it that way. You just want to starting jacking up the engine just enough to take the pressure off the motor mounts. You will see the bolts thru the motor mounts loosen up and when pressure on the oil pan and that's where you want to end. The front bolts will now come out. The back motor mount bolts are a little tricky but with a little maneuvering, you can wiggle the bolts out. Remove the cross member. You don't have to remove the front motor mount. But you have to remove the back motor mount. Remove the rubber motor mount, I believe there is a bolt holding it one. Now the tricky part. You have to remove the rear motor mount bracket. You will need a socket with an extension with a universal to get up in there. There are three bolts holding on the bracket. Once you remove the bracket. The manifold is right in you face. You now can lower or raise you motor for better access to the manifold. Use the same procedure for removing the nuts (pb and heat) and at this time, you wish you would have invested in stud remover (remember, you need metric size ( I think it is 8mm) It makes life a lot easier OK, now you got the manifold off and all the studs removed that are not broke. And here is what I ran into. I used a right angle air drill. Hopefully you have one. If not a right angle extension for you electric drill will fit. Remember to use safety glasses while under the car. I had two in the back and one in the front broke off in the head. What I found with the broken ones in the head, when mine broke, it left a little "tit" on the end of the bolt and it was difficult to get a "center punch" to center because it slid off the "tit" If I had to do it again, I would get a dremel, being careful not to mess up the threads and grind that tit down. Just thinking as I'm writing this, get a flat punch and just tap inside the hole and it should flatten it out enough to properly center punch it. Yep, that's what I would do. Now get a GOOD center punch, making sure you are center and give it a punch. That will shock the stud also. Don't forget to spray pb blaster in the hole too. Now make sure you buy "a good drill bit (5/32"). Don't spare money on this. get at least a cobalt bit, or better (buy several, just in case you break them. They're only $2-3 each, maximum). These studs and not that hard and these bits got thru the stud like butter. Be patient and careful not to hit the threads on the head. REMEMBER, look at the end of the studs you removed, these studs don't go in very far into the head. If you are lucky, you have some of the stud exposed and can grab hold of it, but don't count on it. Get a good center punch on it and when you drill, YOU ONLY HAVE TO GO IN A ¼" OR SO. (DON'T LET THE DRILL BIT HIT THE THREADS ON THE HEAD) ERR ON THE SAFE SIDE UNTIL YOU CAN GET THE EASY OUT IN THE HOLE. Gently tap the easy out into the hole (noticing that the easy out is not touching threads on the head) and attempt to twist out. DON'T FORCE IT TOO MUCH. If you used liberal amounts of pb blast over several days, they will come right out. A couple of mine I was able to twist out by hand once I started them out. Ok, hopefully everything went good. Now you want to polish up the head where the manifold is. I used a polishing pad on my die grinder to shine it up. Don't push real hard and don't keep it in one place. (don't want it to cut on head) and polish it up. Do both sides. Now check your manifold for warpage. Put both manifolds together face to face to make sure they are even. Or use a straight edge. If not you have a couple options. Get new manifolds. Put them back on like they are hoping they pull tight and don't leak. Or do like I did, I got mine shaved down even. Some ORG. guys don't like to do this because they say it puts strain on the y-pipe and they say it will break off the studs again. I'm taking my chances. My y-pipe lined up with no strain after I shaved mine.. so I guess time will tell. When putting studs back in, coat the threads that go into the head with anti-seize. And just snug them in. not super tight but tight. I did not use anti-seize on the threads where the nut is. Get new gaskets, I got mine at advanced auto. You will also need new gaskets for the y-pipe. They are metal ring gaskets. You will probably have to dig out the old ones out of the flange. (you will see when you have it off. I didn't torque my nuts for the manifold. But I snugged them good. I bought the studs, nut and washer locks from Nissan. Now put it back together. GOOD LUCK