Is it my turbo screwed, or something else?

[mooglepimp]

Ok, here's the story. I have a 95 gst with a stock t-25. about 2 weeks ago my friend was taking it around the block when the turbo blew. He babied back to his garage and I took it off the next day. Bought another used t-25 and installed it thursday night. It wasn't in the greatest of shape, had some shaft play, both up and down and back and forth, but it wasn't an outlandish ammount. I've never replaced a turbo before, but I double and triple checked everything to make sure it was all back where it should be. I left his place and drove back to my place, about 10 miles or so. I didn't feel like really getting into it, but I got it going a few times just to see if I had boost. I take a left into my apartment's parking lot and I hear this kinda "crunch" sound. Instantly I hit the clutch and think "Oh shit, not good" There is this sound coming from under my hood, like a coffee can full of bolts is being shaken around. The sound stays the same whether I'm just coasting or babying it along (I've got about 30 yards to go). I park, get out, and smoke is coming out of my hood and my tailpipe. There's a ton of smoke and I am pissed. I just went to bed and figured that I'd check it in the morning. I get up friday afternoon, go outside and start it up. Same GD "bolts in a coffee can" noise, so I shut it off. One of my roommates wakes up about 20 minutes later and I get him to come listen. I pop the hood and go to start the car. I turn the key over and get a lound "GRIND", so I stop.....then I try it again. Car turns over just fine and there is no weird sound. "Rev it up, see if it happens again" I rev....no sound. I get out and we are looking at the engine.....SNAP! The head of one of the exhaust mainfold bolts (back left) snaps off, hits the valve cover, bounces back and nuttags my friend. I run back and shut off the car. I took off the turbo and checked everything out. Shaft play was the same, fins looked ok to me. There was a little bit of oil under my car, but I have a small oil leak, so that was about normal. I noticed that there was a little bit of oil around the line going into the turbo, so I tightened it down a little bit more. I replaced the manifold bolt, made sure everything was tight, then took it out for a bit last night. Some blueish smoke from the tailpipe, but that's about all (I assume it's still burning it off from when it first blew). I had boost and everything ran like it normally does. The only thing that I did differently during the install was removing the boost controller that I had on it, but I don't think that has anything to do with it.

I have no clue what was making that sound, or why the hell it suddenly stopped, or even why a bolt head would snap off. I'm kinda afraid to drive it much 'cause I don't want to majorly F**k something up. Anyone have any ideas?

 

[weith1111]

I'd check the both wheels are still on your turbo and intact, and do a compression test. Bolts in a coffee can makes me think of valve parts bouncing around, makes my stomach squirm. If you check those 2 things out you will find something wrong I'm sure. Depending on how sloppy the turbo is, spinning at 100k rpm any shaft play could sound like hell bouncing around.

 

[mooglepimp]

The valve parts boucing around occured to me.....but would that sound just go away?

 

[weith1111]

Um, yes if they were bashed into small enough pieces they made their way out of the motor, or melted themselves to the piston. Either way, a compression test will reveal a problem.

 

[mooglepimp]

Ahhh, good point. I will do a compression test when I get off work.
Another question that just popped in....if valve parts got busted off....would my car still be in driveable condition? It would seem to me that it would make it undriveable, or at least something would be very noticeable. I'm just asking an honest question, I don't have a whole ton of experience with engines yes, but I'm learning.

 

[weith1111]

So you are saying you are driving the car still? Depending on the damage, it would range from fairly noticeable to unable to run at all. I melted a piston into some strange marshmallow shaped crapball and was still able to drive with just a noticeable HP loss.

 

[mooglepimp]

I am not actively driving it (one of my roommates works in the same building as me, so I ride with him) but I have driven it. I took it out for about 5 minutes last night and really got into it to see if I still had boost, if I could notice anything wrong, etc. Still has as much boost as I expected it to have and didn't notice any funny noises. It does still blow some blueish smoke from the exhaust, but not much. Other than that....I didn't notice anything different. It just really weirds me out that there was this crazy noise, and then nothing.

 

[weith1111]

It's most likely your turbo, so do as I suggested above and you will find out if it's motor or turbo or both.

 

[mooglepimp]

I took the turbo off yesterday and the fins looked ok to me. There is some shaft play, but no more than there was when I put it on. I'll try to do a compression test when I get off work today. I've never done one before, but I will try to give it a shot.