Strange sound, and urgent question..

I've got 3600 miles, since purchase, on the new love of my life, 05 LGT. When I got it, it had the good ol' TMIC to TB hose squeal. After a few days of reading on here, I took care of the angry goat under the hood, and all's been well.

 

Until yesterday, on the way to work I noticed a CEL. Took off gingerly from the next stop, and heard what I thought was a turbo leak, again. After work, before heading home even, I took the intercoola off and checked all hose connections, and found nothing loose. Drove home, and heard some intermittent whining under the hood, but only after about 15 minutes.. then I heard a couple odd pops/clunks. Took it very easy the last 5 miles home, checked all hoses again this morning. All still good. CEL is even cleared now... of which I had nothing to do with.

 

Took the car for a quick round the block to listen, and now there's this, on take-off only:

 

I know it's not much of a video, I can try to get a longer/better example tomorrow. The whine only happens, as I said, for the first few seconds of each shift, and doesn't appear to matter if it's a slow or quick acceleration. The sound cuts off quickly, and I haven't heard it at higher speed...

 

Any ideas? Please?

 

I absolutely love this car, enjoy every second of it, and I really hope I don't have a turbo going out. Transmission? Diff? Exhaust? The axle boots all look to be holding up well, I remember having trouble with them on previous subies.

Will be changing the oil shortly, as I had already intended to do today. I'm hoping for an absence of shiny pieces/sludge and also hope that means the turbo is a-ok. Right after I got the car, I checked the banjo bolt filiters, they were quite clean so I left them in. No turbo replacements that I'm aware of on this car...

 

Also will check for possible exhaust leaks while down there, hoping that may be the whine.. hoping.. Will report back.

Spaceship lgt? Any mods?

I never did get the code pulled before the light went out.. Do our cars store the last known code, even if the CEL is out?

 

And as far as mods, so far the only ones I know of are a K&N (panel) filter, and full unknown make 3" exhaust, with factory tips left on. Up-pipe is still stock on this engine, although I have a catless waiting to be installed.

Okay. Oil changed. Very faint bit of metallic sheen to the last dribbles of oil.. not excessive, in my estimation.

Found a 2-3" hairline crack in the downpipe, right where it connects to the exhaust proper.. sealed it best I could with JB-Weld for now, reasoning that if that's the whine, it should be quieter at least. Proper fix in the future.. while I was at it, heat-wrapped the exhaust from front hanger to turbo.

 

Bad news? still a whine on take-off. Right around 2k RPM, no matter the gear. Still, no difference on light throttle vs hard throttle, just whine right around 2K. I saw no other cracks, hoses loose, anything, so I'm working on the assumption that I have a bearing of some sort going out.

 

Does anyone have any experience with a low-rpm bearing failure/whine of any sort? I still can't in good faith rule out a turbo, but still have no idea.

 

No CEL came on while test driving.. just that verdammt whine.

Aftermarket downpipe.. There was a lower mileage engine (from a 05 LGT limited) put in to the car right before I bought it, and I think the shop bumped the downpipe when installing the engine. Looks like some recent weld right above the crack i noticed.

By "exhaust proper", I believe my tired mind meant "exhaust itself", meaning the first section of pipe after the curve of the downpipe.

With a lack of any other obvious source for my noise, I'm operating on the assumption that my turbo is going out. Upon closer inspection of the oil drain pan, I found some larger-than-dust brass pieces, I'm assuming are shavings of a bearing.

 

I'm still trying to make sense of the odd (to me) timing of the whine only happening at 2k rpm, but maybe the bearing is just making noise at that point for now.

 

Mileage is roundabout 100k anyway, so it can't hurt to start looking for a vf52 and associated parts. I would definitely rather find out that the whine is something less important than have my turbo grenade and destroy my engine.

Man.... should have found out what that CEL was. I'm not trying to be a butthole... I'm just like MAN... that sucks. That was likely key to this issue.

 

I wouldn't jump to any conclusions. You'll end up spending money on all kinds of things that don't solve it.

 

To ME, it sounds like air being blown through a tube. You know, like... damn let me think of examples that might make sense. Like when you blow over a drinking bottle opening. Or... swing a large hollow pipe, like a big PVC pipe and it makes that kind of low... "Wooooo". That's kind of what I'm hearing.

 

It almost sounds like air is being diverted to where it shouldn't be. I guess since we are grasping at straws a bit here, I would carefully, and thoroughly recheck every connection related to the intake system. Especially the BPV. I can't think of exactly what could be going on, but just sounds like air..

 

I don't know man... that's where I would start at least.

 

Also, I'm not familiar with the issue you fixed before. It's just unclear but if you had to reseal the turbo to the intercooler or intercooler to throttle body? How did you go about doing that? Perhaps a piece of some material is caught in the intercooler causing a little back flow at that particular rpm. Or, piece of material caught in the bpv or its' vacuum line..? Or the tube it sends the bypassed air would be a good suspect. Maybe it got left unhooked or popped off? Or the vac line to BPV is off now not allowing the BPV to function.

Does it make the noise when you are in parked/neutral and rev the engine a few times?

Zander, I know... I wish the CEL had stayed on until I could get it pulled. Only time I'll likely say it, but I wish it would come back on so I could find out what code it was.

I'm of the same mindset, i really sounds more like a 'moan' than it does a 'whine'... I'm about to have a couple days off work to really look it all over, and check for hoses/couplings. Also gonna get to the turbo to check for any radial/axial play, bearing-wise.

 

iNVAR, I checked again just now when I got home from work, and nope, no odd noise at all when I'm either not in gear or in gear with the clutch in, and rev it up.. I don't know the vacuum routes well enough to know if there's anything linked to transmission.. gahh.

And you pumped the pedal a few times, to build a little boost, in neutral.... right? Because if there's no noise and you built some boost in neutral, the good news is it shouldn't be your turbo.

Yeah, pumped it quite a few times, varying rpm and coming back to around the 2k "moan zone".. Maybe it's not the turbo, but dang, I'm so afraid of fragging the engine. Like I said, I'll check every hose junction I can lay eyes on after tomorrow.

 

In the meantime, back to a 93 s-10 4cyl 5mt for the daily driver. What a disappointment.

Update for anyone curious, or for future reference.. Still haven't definitely pinpointed the source of my noise, but there is this:

 

[ame=http://www.youtube.com/watch?v=J1DrxGZsulI]05 LGT oem VF40 turbo shaft - YouTube[/ame]

 

That seems like excessive play. You don't get a good idea from the video how much axial play there is, I would estimate 1/8 inch.

 

Checked all hoses/vacuum lines I could get to, nothing cracked or off. The top two bolts at the downpipe/turbo junction were not tight, but all the others were, so no gap. I keep coming back around to turbo replacement. Banjo bolt filter is in place, 85% clear I guess. I'm thinking just go ahead and order a new aftermarket oil supply line system and different turbo.

That's a lot of play. I wouldn't drive on that at all.

 

Strange that it didn't make the noise when you pumped the pedal. Perhaps you weren't pumping it repeatedly enough to build boost? You have to pump quickly to get the boost to build, and you have to rev it up a good bit above 3.5K... not that you should do that now heh, sorry man.

 

Time for upgrade?

Definitely time for an upgrade... ordered an VF40-EVO16G from BNRsupercars today. Waiting to hear form Infamous Performance for an oil line supply line kit, gonna do the whole deal and replace my uppipe while I'm at it.

Definitely time for an upgrade... ordered an VF40-EVO16G from BNRsupercars today. Waiting to hear form Infamous Performance for an oil line supply line kit, gonna do the whole deal and replace my uppipe while I'm at it.

 

Infamous is on backorder. FP has an oil line but the filter is seperate, came to $215 shipped for both for me.

3 days now, driving on the new BNR turbo... and the strange noise is entirely gone. Sounds like a symphony now. Evidently my noise was the turbo bearing going? I replaced the turbo, oil supply, and uppipe, and heat-wrapped the uppipe while I had it apart.

 

Major thanks to m sprank and Bryan@BNR!

 

Now I just have to find someone relatively local to get a tune thrown on this monster.. It's not far off now, I think, but definitely could be more beastly. In the meantime, back to inconsequential cosmetic hacks.