I just completed this repair last weekend on my '99 suburban. While it is fresh in my mind I wanted to add a few notes here and there. In no way am I trying to discount or take credit for anything "Suburban-97" has written. It was because of his excellent information that I even took on this project. I am referring to the numbered sequence that he posted on his "project page."
#2-It was physically impossible to get my hand or a tool on the radiator drain valve of my '99 suburban. Save yourself a lot of cussing and just undo the lower hose on the bottem left side of the radiator. Even this step turned me into a sailor because I couldn't get pliers around the hose clamp. You'll see what I mean...it's hard to get to. When I FINALLY got the clamp off I replaced it with a regular screw down clamp. That .67 cents saved me a lot of braindamage. Those quick clamps are great when you can access them easily.
#7- I was into this step about 10 minutes when I had an "oh shit" moment. This was my longest step by far. I used blue painters tape and a sharpee marker to label all of the wire clips. I labeled both ends so it would be easy to retrace my steps. I also labeled sealable sandwich bags with all of the nuts and bolt I took off. I even put what size of socket I used...this step alone saved me tons of time during reassembly. You will be amazed at how many different sizes of bolts they use..even on the same part. Let me warn you about 2 ugly wiring issues you will have to deal with. There is a black skinny bracket at the back left side of the engine. It holds one or two of the wiring arteries and also holds the ingition coil. See it? I had to remove this completely before I could remove the intake manifold. Just take it off at this point. There is a bolt on the back side of the engine that hold this bracket. It also holds TWO ground wires! You have to undo the first nut to remove the ground wires and then the second nut will allow you to remove that bracket. It's a pain but you'll thank yourself later. The second pain-in-the-butt wiring thing to undo goes to the alternator...runs around the left side of the engine and down below to a ground and two sensors. That ground nut is a biatch! The leads to the sensors are easy to take off. In looking back I think these were the hardest parts of the project. Putting it back together was 10 times easier for some reason.
#11- This step kind of had me scared. Everybody made a big deal about this step but it's really not that difficult. When you reassemble the engine after the intake manifold and plenum (the black plastic looking thing that sits on the intake manifold) are in place you have to slide the distributor gear (about 10" long) down into the engine. If you are one spline off it will put you about an inch out of alignment so it's easy to tell if you're off. I was thinking that I might be 1/8" off and not know it. This isn't the case. I used duct tape and put two 3" strips on the firewall(the back wall of the engine compartment). I put one skinny piece across the top of the distributor cap and took a cut-down Home Depot paint stick and used it as a straight edge to draw a line on the tape. Then, where the stick touched the firewall I made another intersect mark. I used the exact same process for the rotor using another paint stick. Make sure you label them. Leave the rotor attached to the distributor gear. During reassembly you will insert the distributor gear, align it with your paint stick to make sure you're on the right spline. If you're off you lift the gear up about an inch...turn the rotor just a tiny but and slide it down again. Do this until your mark lines up. Then you'll put the cap on (make sure you know which side is in front) and use your other stick to align it with your mark. THEN you tighten the bolt at the base of the Distributor and you're done! (ps. My distributor gear looked perfect so I didn't buy a new one)
#15 I had some trouble with this step. When I removed the metal fuel lines from the plenum a part flew off. Make sure and do as he states...disconnect the firewall side first. A small crescent wrench works great to undo the line at the fittings. Then, between the fittings, there's a #10 bolt that mounts it to the engine. Undo that! Then you can wiggle the lines and remove them from the plenum side. Just do it slowly so you don't do what I did.
#19-He was a genius...the a/c bracket slid just like he said. If anybody tells you to pry the bracket they aren't doing it right! Here's the secret- Remove the bolts like he says...they are all on the front side of the brack and NONE of them require you to remover the pulley!!!!!!! If you look down around the right side of the a/c bracket you will see a nut that points to the firewall. In your mind it makes sense to remove that nut. Don't! Reach down below it and you will feel another nut...you can even see it if you get your head down around that right side far enough. This is the magic nut! If you've removed the front bolts and nut...and then loosen this "magic nut" (don't remove it...just loosen it) the whole bracket will slide forward easily.
#21-This picture alone helped me IMMENSLEY! I printed it off and labeled the different bolts with a pen as I removed them. I'd write "clip" or "wire nut" or "bracket" and draw a line to the particular nut. I didn't purposely use the same bolt in the same hole. I made sure they were the same length and put them in a baggie. I just didn't have a box top handy. You have to pay attention because there are different bolt lengths. Make notes and label as necessary. I cleaned the threads with a wire brush after they soaked all night in white fuel (Coleman fuel).
#24-No, my engine did not look like his upon reassembly! Did he have have a pack of elves working on it or what? Amazing! I only had the weekend to complete this repair and I did the best I could in the time I had. I went through 2 cans of carb cleaner in about 3 minutes. I ended up using my can of White Fuel and a stiff toothbrush. It was economical and worked great! It disolved the engine grime very well. I had a rubbermaid garbage can full of wadded up newspapers. I set the pars on end and scrubbed them. The newspapers cushioned the parts and absorbed all of the yummy gravy. If I could do it again I'd run a bottle of Gunk Engine Cleaner (About $3) through the engine before I even started the project. It will require one extra oil change but I think the time you save would easily cover that extra oil change. My engine was filthy. I can't tell you how much sludge was in the "lifter valley" and on both sides of the intake manifold and the plenum. So much for regular oil changes.
#27- The ball point pen idea was great. My problem was...during my practice sessions I managed to break off 4 ballpoint pens in the bolt holes. I'm a genius! They were easy to extract with a wood screw but still...I swore a lot. Here's my secret. I had to tip the back end of the manifold downward to clear that brass fitting at the back side of the manifold wall. Then I tilted the right side of the manifold down and banked it into the right valve cover tucking it just under the valve cover lip. THEN...I made sure the holes were aligned and lowered the manifold in place. It was a pain but after about 3 tries I had it down. I would HIGHLY recommend buying a larger tube of the black RTV with an applicator nozzle. The one in the kit is undersized and barely allows you to put a 1/4" bead on both ends. Plus, it has no applicator nozzle.
#28 Between the different torque stages...wait 2-3 minutes. This will ensure that the final 11/ft/lb torque will be right on and the gasket will have adjusted to the pressure more gradually. Just my opinion.
Was this an easy project? No! Is it a fun project? NO! My body felt like I had been beaten by a band of gypsies and left for dead. Leaning your body over metal engine parts for a many hours is painful! I finally got smart and leaned my carcass over a life jacket. If only I had done that from the start! Take your time and keep looking over your parts when putting everything back together so you don't accidentally forget about a part! Good Luck!