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2006 STS 3.6
33 Posts
Discussion Starter · #1 ·
My Questions are at the end. This is a detailed overview of all of the work I have done to this car.

Hey guys so I have a 3.6l Cadillac with the luxury performance package on it. I got this car for free because the timing/head gaskets had both failed. I went through and repaired them both. Well I had never done this before so I made a mistake not getting a digital trouqe wrench. So had a small oil leak from the back of the head gasket out of the pcv. Well I had mentioned that timing failed which is normal for this motor, but when it did a camphaser literally exploded and not knowing to me at the time it had nicked the intake phaser next to it. After repairing the engine the car ran but it had other issues due to the previous owners negligance, so I had to repair it. I had to replace all brake rotors and pads, the difference seal gasket was replaced under recall, I had to replace a wheel bearing and center hanger bearing. If your are having electric issues take every ground off and check them and make sure you have no oil on the ground or block I am speaking from experience lol. After repairing these things over time as they came up, I had a very nice STS I really got enjoy the hell out of this car and everyone that got in it would smile when I gunned it. I know it's not coupe, or a v but the car is fast and fun and corners very well while still being comfortable. I really do enjoy it trust me I wouldn't have put this much time/money into it if was fwd and slow. That said the issues I couldn't fix before I started this build were leaky valve covers (I used the wonrg sealent so my fault) This caused my front end of my wire harness to be destroyed due to the oil. This paired with the head gasket oil leak and oil consumption this motor is know for, I was adding oil often. Well fast forward 6 months of driving and I start to hear it ticking that intake phaser decided to say hello but I didn't know for sure until I had that cover off. So with these issues and the oil consumption I was starting to look into pulling the motor.

I saw a lot of people online that said you can't pull it without dropping the cradle. Well I do have experience pulling motors after looking at it and seeing how everything was put in and how much clearance I had. I was like screw it there is nothing stopping me in terms of room or supports. So if you have a ly7 or v6 STS you don't have to drop the cradle to pull this motor so long as everything else is supported It took 5hrs to have it out with a engine hoist. After that I went ahead and tore it all the way down to the crankshaft and the bottom end looked really good per my machinest and some of my buddies at the dealership. I took it my engine block to the machine shop about 45mins away, they are apart of the national engine rebuilding association, So they do all of the work to spec. Which be careful some places will do the work without knowing the specs for your motor and thats how parts are ruined.(10 thousands is what you can remove from the head on 1st gen 3.6) I already had my heads done by them from the last project, but I had them measured and okayed before I used them again. Then I had the block cleaned and checked very throughlly. There was some bad news they were unable to deck it because of the engine boss on the motor won't let the machine cut, the only thing that I know of that can deck a 3.6 is a cnc router. However After getting the mesurements they told me it was in spec which is 2 thousands on the deck. They said it was in spec and I shouldn't have any issues thank God! So I purchased dnj piston rings and bearings and a full rebuild kit through my machinest. I went through and built the motor using an Edmund Manuel with a digital tq wrench so I would be 100% accurate which for a full build is required or you will mess it up. I went and corrected all of the issues like the pcv system oil consumption problem that these motors are despised for with the updated valve cover gaskets, and it has all new timing from last time but the tensioners, guides and oil pump were replaced this build for preventative maintenance. I also replaced the intake camphaser, I bolted every single bolt to spec in squence and replaced all torque to yeild bolts and trouqed them with exact amount of stretch required. As I have been putting everything together it has been checked as I go and I have compression on all 6 pistons, which I had cleaned and stamped. I also have all the rings correctly positioned and make sure you check the directions for the oil rings it's very important because you have more oil consumption because it will allow it through. Also double check all work that wasn't done by you regardless if you had a professional do it or not, this is the kind of thing that everything internally matters and should be thoroughly checked regardless or who worked on it these motors are not simple by any means and there is a science behind all of this. That's why there is marker on my pistons so I could match the diagram exactly. Also when you put the cams in make sure you don't completely top off the stationary hydraulic lifters, I know the manuels say to but don't because when you put them in and compress them if they are topped off with oil they can to have much pressure and it can cause the valves not seal correctly and loss of compression if this happens you have to open the valves to maximum extension and let it sit overnight that will release enough pressesure to fix if that doesn't work, blow out your cylinder heads when they to clean the inside and remove debris in the combustion chamber and valve seats again make sure they are open to clear out the debris. After blowing them out It made compression again, trust me it scared me a lot when I saw 0 when I was doing a compression test, also the reason I was doing a compression test is to find issues like the one above and to know everything is working correctly.All filters including fuel have been replaced with gm or acdelco parts. All I am waiting on is a condenser because the ac needed work as well, before I can finish the rest of it up. because I can't set up the cooling with out it. I will post a follow up when it's all done.

A Side Note to keep your motor clean and healthy.
If your motor is working ONLY PUT MOBILE 1 FULL SYNTHETIC IN IT. Dexos approved oils work but Mobile one has higher heat tolerance than most oils off the shelf, the reason I mentioned this is because the baking and the dark brown you see in the first pic is because someone put in cheap oil. Allyotec motors were supposed to replace ecotec motors and they did but because of this Holden over stated the fuel economy so they made the motor run lean, like crazy lean so it runs hot as hell compared to most motors. So when you put lesser oils into it it will literally bake it into the block and cause that discoloration and sludge which cause way more issues. So only put Mobile 1 in it if you care about it. Also do not wait for the car to tell you when it needs an oil change gm over estimated the oil life on this car and the computer is incorrect to be changed it every 3-5k with seafoam everyother change to keep it clean and happy. Past that enjoy the car and drive it like you stole it!

Thanks for reading this if you got to the end. I know its a lot of info I hope some one will find this invaluable for there STS or the build of one. I really wish I had something like this when I started on my car, but I figured it all to the best of my ability.So now I wanna help out anyone with this motor. If you have any questions or information feel free to post them here or pm me and I will help to best of my knowledge. Info about these motors is sparce so I am always down to help!

My Questions

Miles 144000 roughly

What can I do to make more power if possible without major work? I know mace engineering has cam and cold air intake. Would the intake be worth the money? There is also bolt on super chargers and stuff like that but it's more popular in Australia if you guys have any experience/ideas let me know! I want to mess around maybe push this thing to 400 or 500 hp.

Was using dnj a bad decision? I researched but I still don't have a solid answer. From what I can tell it's a solid brand but anyone that has experience please let me know.

Is there anything you guys recommend me looking into or repairing/upgrading before I start the car?

Or just general opinions or advice that would be helpful.

I will attach my rpo report and some pics as well, like before and After. The pic of my STS is the in-between of the builds.

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