Smoke test blowing straight through crankcase

[relative4]

'05 LGT 5MT, 79K miles, stage 2 w/ Cobb map. Performs great, no real concerns, only idiosyncrasy is it whistles a lot more under boost than my previous 2 LGTs. Like an aftermarket intake, but the intake is stock. Has done that since I got it a year and 7K miles ago; tried a couple different filters, no significant change. I decided to do some smoke testing and boost leak testing to see if the whistling may be related to a boost leak. First round of smoke testing found a split TMIC. I installed a bulletproofed TMIC, no effect on the noise. Did the second round of smoke testing tonight. Builds no pressure whatsoever, all the smoke comes pouring out the oil fill tube at full speed. There's apparently some huge open passage from the intake straight to the crankcase. The only candidate I know of is the PCV valve, but even if that's stuck wide open, I would expect the flow to be a little more restricted than this. I don't think I have a holed piston; pretty sure my symptoms would go beyond a little whistling.

Can someone point out what glaringly obvious answer I'm overlooking? Thanks!

[Max Capacity]

I have to agree the PCV is the first place I'd go.

 

For the whistle, is the silencer removed under the air filter box ?

[relative4]

Thanks. The silencer is there.

[ATLspeed]

If it's not building pressure with the oil off, that's to be expected since it's pathway isn't blocked. I smoke checked mine last week and had a leak at the one of the breather hoses off the VC and IC. Once I get those fixed this tuesday I'll report back.

[d22597]

I ran into the same situation. I even replaced the pcv and still poured out the oil fill. My tuner told me this was normal and to leave the oil fill cap on, but not to let the pressure build more than 5psi.

[relative4]

A few minutes' study of the FSM's intake diagram in the clear light of day showed that the inlet has two unobstructed paths to the crankcase.

 

First is the third connector on the inlet, the big one just past the EVAP return connection and the wastegate return connection. There is a short, thick section of hose going under the intake manifold and connecting this connector to the plastic pipe that goes to the valve covers. The hose must be removed from the inlet, and the inlet's connector must be plugged. Doing this requires disconnecting the bracket that mounts the inlet and the electrical connectors to the intake manifold. There are two approaches to take to the other side of the connection. You can pull out the hose and somehow plug the pipe, or you can leave it open and let it be your crankcase pressure relief (instead of or in addition to the oil fill cap). If you take the latter path, which is probably easier, it will be helpful to attach a hose to it and route the smoke away from the engine bay.

 

Second is the PCV "leak detector", which is just a complete lie. It's a 1-pin ungrounded dummy electrical connector that does nothing. However, it is a little hose leading to the PCV junction and into the crankcase (without going through the PCV valve). It's also impossible to access, being directly on top of the turbo inlet and directly under the intake manifold.

Plugging this one requires removing the TMIC. Then undo an oetiker clamp, unhook the inlet's hose from the PCV junction, and plug both sides. Reinstall the TMIC, and you can finally test.

 

Given that I'm getting good, reliable boost, and that I get not a hint of smoke elsewhere when I plug the oil fill tube with my palm at 5 PSI, and that replacing the split TMIC didn't affect the whistling, I don't think a boost leak is the source of my noise; I'm going to skip this hassle for now.

 

I will pull the intake back out and reinspect it.

 

The only thing that really worries me is the possibility, however remote, that this noise could be an early harbinger of turbo failure, so I should probably pull the DP and check for play to ease my mind. Has anyone heard of whistling preceding turbo failure?

 

I also read one mention of a wastegate problem as a source of whistling. Anybody know about that one?

[Max Capacity]

You may have read that my old vf40 would whine after I had the P0011 and P0021 CEL. That turbo lasted a 1000 miles until one morning when a 1/2 mile from the house it began to whistle. That's when I replaced.

 

http://legacygt.com/forums/showthread.php/142-000-miles-oem-turbo-168561.html

[relative4]

Thanks Max, I'll go ahead and pull the DP.

[Dishwasher]

I have a whistle, I'm pretty confident it's a leak coming from my dp-exhaust junction. I haven't gotten around to addressing it yet.

 

 

Sent from my iPhone using Tapatalk

[Max Capacity]

Thanks Max, I'll go ahead and pull the DP.

 

 

Better safe then sorry.

 

The first pulling of the DP is the hardest, after that its easy. Make sure you have some PB Blaster and anti-seize compound for putting it back together.

[NotYourAvgSpec.B]

Check shaft play while you've got it off.. also are you running the stock recirc valve? They can only handle so much boost before being pushed open and can whistle.... Is the whistle only under boost?

[relative4]

are you running the stock recirc valve? They can only handle so much boost before being pushed open and can whistle.

 

Thanks, I was wondering about that, have considered it a strong candidate once I make time for a proper boost leak test. Anyone know the boost capacity of the stock BPV? I live at 5300 feet, and I generally see peak boost of 15.3 PSI.

[NotYourAvgSpec.B]

I'm running 20psi in S# and stock bpv, well stock with stronger spring. And don't notice. Of course it's hard for me to hear much over the 3" tbe and short ram

 

What air intake are you running... And when was the last time you cleaned your throttle body?

 

 

But back when I had an 05 obxt w/ vf-52 it definitely became a problem.... With 22 psi peak I had to upgrade to a hybrid three port bpv