Garrett VNT15 Actuator Wear - Overboost? OH, *that's* why!

In the middle of a marathon series of (mostly) maintenance tasks on my 2002 VW Jetta TDI w/ ~250k miles (head reconditioned by Frank06, block cleaned and prepped for head gasket, new high mileage timing belt kit, etc.) and while diving in to cleaning the turbo while it's off the car, I came across a rather disheartening sight.

Note the significant wear on the actuator ring (bottom of pic)




When I pulled the ring, I could actually see some of the metal that had been worn away still hanging on at the edge


The internal ring actuator lever has apparently had the upper 80-90% of its ring actuating profile worn off by ~10%



My assumption is that the ring and lever had enough play in their vertical alignment to each other that the buildup of carbon caused the lever to not maintain a complete contact surface w/ the ring. Thus, as the ring became less able to rotate smoothly, the lever was worn unevenly. Its possible the bottom sliver of unworn lever may even have been getting trapped by the outer surface of the ring when the two connected.


Per this thread from 2003 (Anatomy of a Failure: VNT actuator wear (images)), I suppose it is possible I can have the lever and ring both welded to have the missing material restored. No clue how to go about finding a local 'die repair shop' to do the work.

Just thought somebody might be interested, especially if you've been chasing your tail on an unresolvable overboost issue.

Had that happen to one of my past jettas a few years ago. I bought a spare turbo at the pull and pay for $50 and just used it for parts as i needed them if you can get lucky and score one that way.

I am sure that's what the inside of the one I pulled off my 03 at 305k miles looks like. Took a while to find since it opened / closed at the correct vacuum levels and all the standard limp mode testing passed. I was cleaning the intake and had a better view and feel of the actuator and noticed how much "slop" there was in it. Low mile used one and it's good to go!!!

Nice to hear some confirmations. Thanks.

I actually do have a spare turbo I snagged at a Pick n Pull last year. Opened it up a few weeks ago to get some insight into the one on my car and it honestly looked a little bit better than the turbo above. Still, I'm feeling a little bit squeamish about replacing a turbo that I know (mostly) works with one that I am uncertain of both its operability and history.

I guess my immediate options are:

• reinstall current turbo as is
• attempt to find a die repair shop capable of welding more metal into the worn elements of the current turbo
• install the Pick n Pull turbo after giving it a more thorough evaluation
• purchase a rebuilt (prob from Dutch Auto Parts)

Going to try finding a shop that can handle the weld job and confirm price. Will prob reinstall turbo for the interim to get rolling again.

I was in the same boat knowing that my turbo was a good one and the picknpull one was unknown. I just chose to part out the junk yard turbo and make my turbo good again

Another one on the same topic:
http://forums.tdiclub.com/showthread.php?p=5549770#post5549770

friction
mans best friend!

I guess it just seems like there ought to be some way to have a replacement piece that just bolts in. I suppose between the vibration and heat, other means of attachment are simply implausible.

Mongler98 said:

friction
mans best friend!

Click to expand...

oh man. thats funny. lold so hard. our friend. mechanical moving parts, not so much. Only thing we want friction for is breaks.

hyoomen said:

In the middle of a marathon series of (mostly) maintenance tasks on my 2002 VW Jetta TDI w/ ~250k miles (head reconditioned by Frank06, block cleaned and prepped for head gasket, new high mileage timing belt kit, etc.) and while diving in to cleaning the turbo while it's off the car, I came across a rather disheartening sight.
Note the significant wear on the actuator ring (bottom of pic)

When I pulled the ring, I could actually see some of the metal that had been worn away still hanging on at the edge

The internal ring actuator lever has apparently had the upper 80-90% of its ring actuating profile worn off by ~10%

My assumption is that the ring and lever had enough play in their vertical alignment to each other that the buildup of carbon caused the lever to not maintain a complete contact surface w/ the ring. Thus, as the ring became less able to rotate smoothly, the lever was worn unevenly. Its possible the bottom sliver of unworn lever may even have been getting trapped by the outer surface of the ring when the two connected.
Per this thread from 2003 (Anatomy of a Failure: VNT actuator wear (images)), I suppose it is possible I can have the lever and ring both welded to have the missing material restored. No clue how to go about finding a local 'die repair shop' to do the work.
Just thought somebody might be interested, especially if you've been chasing your tail on an unresolvable overboost issue.

Click to expand...

any metal fabrication shop worth their salt should be able to fix it. No chance on replacing the actuator and ring?

I mean, I struggled enough to find a local shop able and willing to run my intake in an ultrasonic bath. It's completely reasonable that there's a die repair / machine shop that can fix up the lever and ring. Not sure how I'm going to find a local shop, especially that I can trust to do it right, though. Some services just aren't as readily searchable on the Internet.

hyoomen said:

I mean, I struggled enough to find a local shop able and willing to run my intake in an ultrasonic bath. It's completely reasonable that there's a die repair / machine shop that can fix up the lever and ring. Not sure how I'm going to find a local shop, especially that I can trust to do it right, though. Some services just aren't as readily searchable on the Internet.

Click to expand...

all you can do is call and state what you need done. They may or may not request more information. that lever had to be put in the housing somehow. and im sure they could make a new ring for the vane. may or may not be cheaper than a new turbo.

DivineChaos said:

oh man. thats funny. lold so hard. our friend. mechanical moving parts, not so much. Only thing we want friction for is breaks.

Click to expand...

Then we all die
Everything relies on friction to operate. Ita how we use it to our advantage.
Sorry of you cant hear sarcasm from the other side of the internet!

There are places out there that sell the VNT parts. I didn't realize they could be purchased so cheaply (from china so that shouldn't be a surprise) - but might do the trick
https://www.ebay.com/i/223576611191...kPTFOuhLUsVH2p8nhTYQfDfHDuk3C41IaAhPdEALw_wcB

I too never knew about the availability of replacement control rings as Garrett does not sell them. You never know the source or construction of parts that are sold on ebay. There are UK sellers that use first quality materials in rebuild parts. There are a few U.S. ones as well, but I have not looked in years. You might contact G-Pop Shop turbo re-builders for a U.S. supplier.

On the bright side, I checked my pick n pull turbo again last night, and it turns out it is in significantly better shape than my current turbo. I don't think I even really did much cleaning last time I opened it.





Guess I'm going to take a chance on the PNP turbo. Sure wish there was a checklist of how to evaluate a junkyard turbo for viability before installing.

Fins look good, spin looks good, shaft play looks good radially and axially, mechanisms are free of obstruction and wear. Not sure whether I should dismantle the CHRA to check anything out.

Well crap, I knew something didn't quite seem right. As best I can tell, looks like the pick n pull turbo I have that's in awesome shape is a Garrett VNT 17/22, NOT a VNT 15.

While I suppose that's pretty neat in terms of junkyard find, it does me little good in terms of getting back on the road this week. Guess it's back to cleaning the old VNT 15 I already had.

I came across this one a few months ago but I have not bought anything from them.
https://mecevo.com/index.html