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Question about the variable vanes in the turbo
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Author:  kissfan79 [ Fri Mar 15, 2013 1:22 pm ]
Post subject:  Question about the variable vanes in the turbo
Hey guys....
I have a couple of questions about the variable vanes in the turbo on the CRD. I was checking the actuator arm the other day for movement and when I disconnected the vacuum line the actuator arm didn't move. The last time I checked it (roughly late summer or early fall) the actuator arm moved just fine. (although on a side note- there was no change in the exhaust tone when the arm dropped down. Geordi noticed the same thing when we got together when he was in the area last year. He wondered about it but didn't seem tooo concerned about it).
My first assumption was, of course, sticky vanes to which I did try some hard runs to get my turbo hot to free them up. I even had some hard pulls with my 4,000 trailer that should have heated it up a bit. So far......no go on freeing them up. I did the bypass check to make sure the solenoid wasn't wonky. When I disconnect the vacuum line from the little black device and put my finger where the vacuum line that goes to the actuator was there is definitely suction. Are there any known instances of the actuator itself failing or are there any other problems that can cause the vanes to stick and the actuator arm to not move? I haven't noticed any loss of driveability whether at idle/stop or whether at highway speeds. It also hasn't thrown a CEL. Any ideas?

Thanks, Jim
Author:  papaindigo [ Fri Mar 15, 2013 6:38 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
Odd. On a stock CRD turbo, not the GDE stage 2 turbo, the standard vane movement check per GDE is "You can check the vane functionality at idle in park. Underneath the vacuum actuator on the turbo is rod extending downward connected to the vane mechanism. If you pull off the vacuum line at the turbo, the arm should drop about 1/2 inch and then raise back up after reconnecting the vacuum line. It is a bit difficult to see the rod, but this is the easiest method to check for proper VGT vane movement." Since this is done at idle I would not expect much if any change in the exhaust sound.

The vanes are moved by vacuum so failure could be:
1. no vacuum - there are several possible causes including a heat fried vacuum line under the coolant tank but should throw a code and bad performance
2. sticky vanes - generally bad performance but I suppose it's possible that they could be stuck in a not too bad position, if you get my drift
3. bad vacuum actuator itself (e.g. the puller doesn't pull) - I'd have to dig out my old OEM turbo, can if you want, to check and see if it's separate from the turbo

The typical fix, Italian tuneup, assumes sticky vanes and seems to work but may require multiple runs. Alternatively I've seen some posts involving successful use of oven cleaner to unstick vanes but lack details.
Author:  kissfan79 [ Fri Mar 15, 2013 7:10 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
Papaindigo...
Thanks for the reply. That is indeed how I was checking the vane functionality. I had it in park at idle and I pulled the vacuum line (although I usually pull it from where it plugs into the little black device hooked up to the solenoid.....the one with the "vac" and "out" labels on them. It seems to be easier than prying the vacuum line of the actuator itself). Back in the fall.....I could definitely see the rod drop and rise when it was pulled and reconnected. Now.....nothing. After pulling the vacuum line.....I would put my finger over the little piece that the vacuum line attaches to and it definitely has sucking to it. (I guess I should actually pull it from the actuator on top of the turbo to be sure nothing is wrong with that connection). It seems to be making all the right buzzing sounds and such and the bypass trick didn't help. What I was really wondering is if indeed the actuator itself can go bad. I haven't hear of it happening from anyone here but you never know. As you hinted at.....I wonder if it is stuck in a "middle" position that doesn't really hurt the low end or higher end power. It's just bugging me as I knew they were functioning fine back in the fall. I'll try a few more hard runs at it. Other than the actuator not getting proper vacuum...are there usually any other signs of something gone awry with the vacuum system?

Thanks, Jim
Author:  papaindigo [ Sat Mar 16, 2013 11:00 am ]
Post subject:  Re: Question about the variable vanes in the turbo
I have not pulled my old OEM turbo out of it's dead storage box but I can see thru the plastic protective lining and based on that:
1. the vacuum actuator mounts to the turbo with either 2 or 3 bolts, I can see 3 but I'm not sure what the middle one does, and I presume, cannot see clearly, that it can be disconnected from the actuator rod running down to the vanes. I presume it is possible for this part to fail although why I don't know nor do I know if it can be fixed nor do I see it as a separate item in the parts fiche which may or may not mean anything. Guessing here but I suspect it would be possible to hook a small vacuum pump up to the actuator, don't know the appropriate vacuum values, to see if that would move the vane rod. If it did then that would tell you that the vanes and the actuator are ok but the vacuum being pulled by the vehicle is too low for some reason.
2. I cannot tell you if pulling on the actuator rod would help in diagnosis. Presumable it's "pullable" and if pulling it makes the vanes move you are back to either the actuator has an issue or the vacuum has an issue. If you want I can dig into my old turbo and check what pulling this rod does. Feel free to ask as it's not that hard to get to.

If the actuator arm does not move when tested something is not right. I still lean toward sticky vanes and note that the Italian tuneup is usually effective it's not always so and if that's the case there are other options.

You might drop Keith at GDE an email and see what his thoughts are based on this chat.
Author:  kissfan79 [ Mon Mar 18, 2013 1:55 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
Papaindigo,
Thanks for the offer to check your turbo. If it's not too much trouble could you indeed check to see if the actuator rod is pullable by hand? I was watching a video on line a while back in which a mechanic was tearing down a variable vane turbo and he had it partially apart. When he pulled on the rod on that turbo, you could see the vanes adjusting. I started up my Jeep and pulled the vacuum line from the actuator itself on top of the turbo (just to verify there was nothing wonky with the vacuum line running to it) and still no movement but there was definitely some good suction coming from the line. I reached down in there and tried to move the rod by hand both with the vacuum line on and off and both both times were a no-go on moving by hand. I'm going to take her out tomorrow (kinda' cool and rainy today) and do some hard runs from a stop in succession to see if I can get them unstuck if that is indeed the problem. in the meantime....I'm going to take your suggestion and e-mail Keith.

Jim
Author:  ChooChooman74 [ Mon Mar 18, 2013 2:43 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
You may want to do a search for my post about my turbo issues. My vanes were AFU from possibly pieces of glowplugs going through. That's just an assumption. Those pieces did leave their mark on my pistons.

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Author:  kissfan79 [ Mon Mar 18, 2013 3:08 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
ChooChooman,
Thanks for the reply. I do remember reading those posts before. Hopefully it's nothing like that. I'm going to go back and re-read them but to recap.....did whatever it was glowplug piece or otherwise lodge in your turbo vanes or go through them altogether?

Jim

EDIT: Searched and read some of your posts about the piece going through the turbo and looked at the pics of when you pulled the turbo.
Author:  ChooChooman74 [ Mon Mar 18, 2013 5:13 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
kissfan79 wrote:
ChooChooman,
Thanks for the reply. I do remember reading those posts before. Hopefully it's nothing like that. I'm going to go back and re-read them but to recap.....did whatever it was glowplug piece or otherwise lodge in your turbo vanes or go through them altogether?

Jim

EDIT: Searched and read some of your posts about the piece going through the turbo and looked at the pics of when you pulled the turbo.

I did not find any pieces, so it went through. Good luck with yours. Taking a turbo off, it can be done in under 2 hours.
Author:  papaindigo [ Tue Mar 19, 2013 11:25 am ]
Post subject:  Re: Question about the variable vanes in the turbo
I don't know if that rod can be pulled by hand with the turbo on the vehicle as access may be an issue. I can tell you that I partially opened the box with my original OEM turbo so I could get access to the rod. With a regular slotted screwdriver placed across the turbo housing and under the shaft retaining nut the shaft moves up/down with about as much effort as I would expect if the vacuum driven shaft mover had a spring return loaded diaphragm inside or in other words only a slight bit of resistance. My bet remains gummed up vanes.
Author:  kissfan79 [ Tue Mar 19, 2013 11:49 am ]
Post subject:  Re: Question about the variable vanes in the turbo
Thanks....I appreciate it. I got a reply back from Keith and he did recommend applying vacuum to the actuator and holding it for at least a few seconds to ensure that the actuator isn't leaking vacuum. I'm also going to get a vacuum gauge to check the amount of vacuum coming from the vacuum line to make sure it is sufficient to operate the actuator. He also suspects sticking vanes from excess soot and that I may need to actually remove the turbo and disassemble/clean it. :shock: Hopefully.....I can get them freed up from several hard accelerations and won't have to go that route.
Author:  geordi [ Tue Mar 19, 2013 11:59 am ]
Post subject:  Question about the variable vanes in the turbo
If you have a vacuum source, you could also clean the turbo without running the engine at all. Some have had good luck with using Easy-Off oven cleaner. If I were in your situation, drowning the exhaust side in the stuff would seem like a good plan.

You would need to remove the upper heat shield and pull aside the water bottle, then unplug the exhaust line from the back of the turbo. That will give you access to the exhaust side and the vanes with the least amounts of hassle... Such as it is. From there, filling it up and letting it soak, then maybe spinning the turbo by hand and flexing the arm with your vacuum pump... And hoping. At least this is less of a risk to the bottom end than a series of abusive Italian tune ups.

Good luck.


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Author:  kissfan79 [ Tue Mar 19, 2013 12:00 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
I went back and found that video I was looking at a while back that showed a VGT turbo broken down. Turns out it is a Garrett VGT turbo that he took apart and put back together. Pretty interesting as he show the vanes and how they work.

http://www.youtube.com/watch?v=4rj6pmnY0XI
Author:  kissfan79 [ Tue Mar 19, 2013 12:07 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
Geordi,
Thanks for the advice. That was the reason I haven't run it really hard in order to try and free up the vanes. I have done a hard run here and there but haven't done several back to back to back for fear of subjecting the engine to a lot of high rev abuse. I have read about folks using the easy-off but what would you use to rinse it out with (or would you just leave it in and hope the residue burns off)?
Author:  geordi [ Tue Mar 19, 2013 3:00 pm ]
Post subject:  Re: Question about the variable vanes in the turbo
You don't need to do anything to rinse it out. More importantly you don't WANT to do anything to rinse it out. The turbo is all one-way-flow, and the carbon should be loosened by the easy-off and simply blown away by the exhaust flow once you get everything loose in the vanes.

The heat from the exhaust will burn off the cleaner, but your exhaust may smell like a refinery fire for a while. Once you know everything is working smoothly, a long hot drive will be all it needs to dry everything off.
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