[95TA - The Beast]

I have not seen anyone do a turbo replacement write-up, so I figured I would cover all the salient information so people know what they are getting into.

First off, the information presented here are my personal observations. My vehicle is a 2014 Cadillac CTS-4 2.0t Performance model. But, as well known it is exactly the same engine/turbo/exhaust downpipe as what everyone else will come across and experience, so it is still relevant. I also follow OEM directions and when they state replace something, I will cover that as well. I WILL give my personal opinion in regards to what I feel can be reused, but when the FSM states to replace something, I will also state that the FSM says to replace it.

This is not some major operation and it is doable by anyone that can turn a wrench. Just make sure you have ALL the replacement parts on hand when you start and you will be quite successful.

Fluids:

To begin with the FSM states to drain the coolant via the radiator. The FSM states that you must vacuum-fill the cooling system. Personally I took this route myself as I have the equipment. I found that the entire process was simple, clean, quick and thorough with minimal dripping when I disconnected the lines at the turbo. Upon reassembly, vacuum-filling the entire system was a one-shot deal with no burping or anything else necessary. I only had to check the overflow once after restarting the car, letting it cool and adding fluid, then again a week later as it just dipped below the "full cold" line after a weeks worth of running (about 200 miles) which finally purged any minimal air in the system out. I cannot stress enough about how well this process worked.

If you have a low-mileage car, by all means reuse the coolant you have. In my case I was at 42k miles and being 7 years old I decided it was perfect to just replace the coolant with new. If you are going to reuse the coolant you remove, just be sure to clean the area below the car and especially around the area where the coolant will drain from thoroughly and drain into a clean container. All makes/models are different, but in my case it was about 2 gallons of coolant that came out and needed to be refilled.

In regards to oil, it is not a requirement to do an oil change after replacing the turbo. For "thoroughness" it wouldn't be a bad idea to do an oil change as part of this process, since you will have the car up in the air anyways.

Disassembly:

First off get the car in the air. Personally I used ramps for the front with wheel chocks at the back tires.

- Drain the coolant. On most models there will be a drain petcock on the passenger side of the lower part of the radiator. Use a larger 5-gallon drain pan and it will contain whatever comes out, regardless of make/model.

- Remove the top engine cover. One torx bolt, the dipstick and the oil fill cap need to be removed and the cover lifts a little up at the front and gets pulled forward to remove. Put the dipstick back in, the oil fill cap back on, and I like to put fasteners back in place to not lose them, so put the torx bolt back into the valve cover.

- Remove the turbo heat shield. Three bolts hold the heat-shield to the turbo, one on top and two in front. Since these are long and turbo may be rusty, I just put these with the heat shield itself.

- Remove the airbox cover and intake piping. Looking at the fresh-air tube (big braided line on mine) that goes into the larger air piping you will see a small lever at the connector, move the lever all the way over and pull the fresh air tube off the piping. The airbox cover is bolted to the lower box, so undo those fasteners. You do not need to remove them all the way, just enough to disconnect the cover, that way they don't get lost. Unscrew the band clamp holding the piping to the turbo inlet to loosen the clamp. Disconnect the MAF sensor wiring connector at the cover and disconnect the harness mount from the piping as well. Drape the wiring and connector out of the way and remove the airbox cover and piping as an assembly.

- Disconnect the bypass valve electrical connector and the wastegate solenoid electrical connectors. This will allow the harness you removed from the intake piping to be pulled completely out of the way.

- Undo the bolt holding the coolant return line from the valve cover. The return line is the solid metal line that goes vertical above the turbo. As a side note: This is the ONLY line on the turbo that is a hardline from the turbo that is bolted elsewhere. The rest of the lines off the turbo (oil/coolant/vent) all have hose sections that allow those lines to flex away from the turbo for installation/removal.

- Remove the banjo bolts for the coolant feed and return lines. They are at the side of the turbo; the feed at the bottom, the return at the top. Be sure to only undo the banjo bolts enough to remove them from the turbo but not enough to allow the washer to fall away that is on the turbo side, but be sure to keep the banjo washers with the bolt as they will be reused. The FSM states to replace them, but they are metal with rubber and can be reused if they are in good shape.

Side-note: I have been told that if you do not want to drain the coolant via the radiator, that you can use a drain pan below and catch whatever comes out of the lines upon disconnection. Personally this creates the possibility of a LOT of the coolant coming out of here and creating quite a mess, along with the real possibility of creating an air-pocket in the system after refilling with the increased hassles of trying to get such an air-pocket to "burp" fully. Thus I still stand by my original recommendation to fully drain and fill the cooling system per the FSM.

- Remove the upper coolant return line by disconnecting it from the return hose at the valve cover.

- Remove the air discharge fitting from the bottom of the turbo. I found I could get a ratcheting combination wrench as well as a 1/4" ratchet on the two bolts that hold the air discharge fitting to the bottom of the turbo charger to remove it while standing working from above. If you are not as talented, you might find it much easier to do from below. Given that mine is a Cadillac CTS with AWD I had a ton of stuff in the way from below so I took care of it from above. Tip: The bolts are centered to the fitting with two plastic sleeve grommets. If you loosen them both a bit, then undo one until it just disconnects from the turbo then undo the other until it also just disconnects, both bolts will be held in place at the fitting, making reassembly an easy job. If you lose those sleeve grommets, you MUST get new ones as they center the fitting on the turbo outlet. The gasket used on this fitting more than likely will be reusable. If the black rubberized portion is compromised at the raised embossed area, you are better off getting a new one. Once disconnected this fitting will just flop and hang there.

- Remove the oil feed and return lines. The upper feed line is held in place with a banjo bolt. Again be sure to keep the washers with the banjo bolt upon disassembly. If they are still in good shape they can be reused, if torn or the rubber compromised, replace them. The return line at the bottom is held in place with two bolts. Again I was able to get them both from up top. Follow all the same guidelines used for the air discharge fitting with the oil return fitting at the bottom, including inspecting the gasket and if it is compromised, replace it. In my case it all came apart clean and in perfect shape with all the rubber intact so I just reused what I had.

- Remove the downpipe from the turbo. The downpipe is held in place with 4 nuts that connect to 4 studs that are threaded into the turbo itself. The downpipe is held in place from below by a support bracket, so it is safe to remove all 4 nuts and the studs to get the turbo out. Now, with that being said, if you have a 2016+ model vehicle all the studs should come out after you remove the nuts without problem. I personally used a 3/8" drive 7mm socket to accomplish this, along with PB Blaster to help ease them out. Note: If you have a 2014-2015 (and possibly early 2016) vehicle, you will run into the issue where the lower right stud (the one closest to the engine at the bottom) is literally cross-threaded and jammed into the turbo. They did this on purpose (as evidenced by the different turbo part number in 2016). They wanted to know if anyone messed with the turbo/downpipe/etc and in doing this you need to actually remove the downpipe entirely to get the turbo out. If you are like me, I am not that easy to dissuade, so I ended up using two nuts and ripped the stud out of the turbo. In doing so you will notice that only about 1/3-1/2 of it was jammed into the turbo with the remainder of the threads on the turbo intact. It isn't a total PITA given that is the ONLY hole you can get to from behind to retap the threads easily once the turbo is out of the car. You WILL need to source at least that one new stud and a new nut if you have this situation.

- Remove the vent pipe. This is the pipe that has a fuel-line like connector at the inlet of the turbo. The FSM doesn't expect you to remove the line at the fitting, they expect you to remove the small allen bolt and remove the line and the fitting from the turbo itself. Personally that seemed like a huge PITA, given that the steel adapter at the turbo is in with an o-ring and with the turbo being aluminum there would be a ton of heat and pressure applied to it in its life, usually making removing those a total PITA, especially at the angle it is at. The reason they expect this is that a standard fuel-line removal tool (the metal kind) will not fit with the angle the line has going into the fitting. So really you have three options: 1) remove the line with the turbo by undoing the OTHER end of that line (the nylon hose that plugs into the connector at the top of the valve cover, probably the easiest option), 2) undoing the allen bolt and pulling the fitting adapter out of the turbo (I cringe at this one on a turbo with any real mileage) or 3) disconnecting the fuel-line like fitting and pulling the pipe there (I did this method by making a plastic disconnect tool out of a nylon bushing that was a bit larger than the fitting itself, cutting a section out of the side that allowed me to get it around the lower pipe, squeeze it together and get it up into the fitting, being careful to make sure it was all the way around to ensure it contacted all 4 "prongs" of the retention mechanism, pushing it all the way up into the fitting and lifting the fitting off the pipe. Again, I have many years of doing this kind of stuff and it sounds easier than it is.)

Whichever method you choose, just take your time and work through the process.

- Remove the nuts securing the turbo to the exhaust manifold. These 4 nuts should come out easy enough, and again I used PB Blaster to help. If you left the downpipe in place, and if the lower right stud off the turbo to downpipe is still in place, you may have to remove all 4 exhaust manifold studs to get the turbo out. In this case if you have a 2016+ vehicle, again, you are in luck as all should come out without issue. If you have a 2014-2015 (and possibly early 2016) you will find that they also cross-threaded and jammed the upper right stud into the exhaust manifold the way they jammed the lower right stud into the turbo for the downpipe. Again, they wanted to know if anyone messed with the turbo setups, so they set up a trap by jamming the stud in cross-threaded (as evidenced by the new exhaust manifold part number released in 2016, and if you find any used exhaust manifolds from any models for 2014-2015 you will see that they ALL have the upper right stud still in place with all the rest removed). Once again this is not a "blind" stud hole and easily tapped from behind to clean up the threads (on both stuck studs they only jammed them in 1/3-1/2 the way and the stock studs thread all the way to the back, so retapping the threads is a valid fix). So, figure out what is best for you and get the stud out or pull the downpipe if you have an early model. If late model you won't even need to remove these studs if the studs are off the turbo for the downpipe. If you rip the stud out and retap the manifold you will need to source a new stud and a new nut.

The turbo should be out of the car at this point thanks to the small hose sections they had built into the oil lines and coolant feed line.

- Remove the exhaust gaskets from both the exhaust manifold and downpipe. Now, I have had people say they are reusable, but quite frankly, they are not. There is no spring ability for those gaskets to "self heal" the way the rest of the gaskets have. They are graphoil gaskets held in a stainless crush ring that once crushed is done. You MUST replace them both.

Maintenance:

Now is a good time to replace whatever lines you don't like, get whatever gaskets are not in good enough shape, and whatever studs and/or nuts that didn't survive the removal process. In my case I was putting in a ZZP Big Wheel turbo unit that come already assembled, so I just moved over the braided lines for the wastegate control, the bypass valve, sourced a brand new coolant return line (my stock one had a little corrosion on it and the new unit was pristine with all new wastegate actuator and all, so I wanted it all to look "like new"), bought all new exhaust manifold studs and nuts, all new turbo to downpipe studs and nuts, new exhaust and downpipe gaskets, and since I needed to retap the exhaust manifold stud hole, I actually pulled the exhaust manifold to do it (in hindsight there was more than enough room to do it on the car) which required a new exhaust manifold gasket and new exhaust manifold bolts (torque-to-yield with a very specific adhesive to lock them in place once torqued).

Due to the retapping is how I found out about the new part numbers and in talking with a few people that have worked on these cars it was evident that GM was worried that people would try modifying things early on.

Tip: If you are going to retap the exhaust manifold with it on the car, be sure to stuff rags or paper towels into the exhaust ports to keep metal shavings from falling in. Be sure to blow everything off with compressed air before pulling those rags/paper towels out and starting reassembly.

Clean everything up and get everything ready for reassembly.

Reassembly:

Honestly, if you got it all apart, you can get it all back together. Reassembly is opposite of removal. There is really no big issues to be found, no real cheats. Just be sure to make sure the gaskets are centered and in place as well as the banjo bolt seals. I personally used copper never-seize on the exhaust stud to nut connections, as well as the bolts that hold the heat shield in place. That just makes it that much easier to remove in the future.

There is a torque-spec for the exhaust nuts that go on the studs, but that does not apply to reused studs/nuts (believe it or not, but they actually consider those torque-to-yield). Just make sure they are good and tight. Again be sure to use new gaskets for the exhaust manifold to turbo and the turbo to downpipe connections. As far as the bolts and banjo bolts that go to the turbo, I will make another post with those specs, but, honestly, just don't torque the piss out of them and you are good. I have found everything is minimal torque values.

I will edit the extra post below with pics of the torque-sequence and torque-values if you use all new studs/nuts. Basically, as in all cases, just use a cross-bolting pattern and you are good (upper-left, lower-right, upper-right, lower-left for example and do it in 3 passes).

Be sure to use a vacuum-fill for refilling the coolant (best $65 ever spent) and pull a full vacuum on the system for 10 minutes prior to filling. Another tip: once vacuum is pulled, open the filler slowly to allow coolant to fill the filler tube, then close it and pull vacuum for another 5 minutes to make sure there is minimal air in the system. You may have to use a rag on the air vent during the second evacuation to make sure coolant doesn't go flying out of it if any got sucked into the system purging air from the fill line.

I will see about posting up pictures if I can find some and do some annotating. I didn't take pics doing my swap, sorry.

[95TA - The Beast]

Placeholder for Torque Specs/Pics.

[turbojeep95]

Nice job on the write up! Maybe throw in some pics if you got any.

[SS_AL]

Thanks for taking the time, I've been planning to upgrade my turbo.....Very Informative

[95TA - The Beast]

Thanks, I really haven't found any pictures, but I have another opportunity coming up as I am pulling the engine to do forged internals.

I am hoping I can cover the pull, tear-down, blueprinting, assembly and reinstallation.