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02-13-2018, 08:44 PM | #1 |
Scooby Newbie
Member#: 464251
Join Date: Mar 2017
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05 sti blowing tons of white smoke
Hello, I am in need of some insight with an issue I am facing. I have done tons of research, and can't find something like what I am facing. 05 STI, 102k miles, 2.5l stock block. Car runs great, other than the clouds of smoke it plows out the tail pipe. As for mods; catted full cobb exhaust. The car wasn't tuned for the mods by the previous owner (I know, dumb), but I'm not 100% sure that's the cause of the issue. I've successfully rebuilt ej's before, but I don't wan't to dive into this one, as it doesn't seem like it's the rings.
Here's what happens; On a cold start, smoke is quite minimal, but gets a bit worse as it starts to warm up. The smoke does smell like oil, nothing like coolant. I go for a drive (still smokes), park it, and shut off the engine. Looking at the tail pipe, its still smoking even with the engine off (but obviously not as much) - this gets me thinking turbo seal. I start it up after sitting for 10 seconds, and boom TONS of white/blue smoke comes out the back (can't see through it). Now this does seem like some sort of seal, doesn't it? I pulled the downpipe off, after the car cooled down of course, and it's black (guessing normal), but no gunk. Just the black exhaust, no signs of caked oil, no signs of cracks. Car does build boost fine, but I have been light on the throttle due to the issue. I haven't really driven the car since the smoke started happening, so maybe the turbo seal is just starting to go out? There is no shaft play at all on the turbo that I can feel (axial, or radial), and spins freely. I have cleaned out the pcv valve, and no dice. No oil in the inter cooler or cold side of the turbo that I noticed. Pulled the oil cap with the engine running, and no smoke. Oh also, if I tap the throttle, more smoke does come out as well. I'm a bit lost here. I'm thinking worn valve seals? Maybe the turbo seal is bad? I have heard that the turbo seal can go bad, even though it has no shaft play. Also I noticed the car smoking at the header, and some oil around it, not sure what that might've been. Anyways this got pretty long super fast haha. I could really use some help brainstorming here. Haven't really dealt with this issue, so I am a bit lost. Help would be greatly appreciated.
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02-14-2018, 09:37 AM | #2 | |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
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02-14-2018, 02:17 PM | #3 | |
NASIOC Supporter
Member#: 30669
Join Date: Dec 2002
Chapter/Region:
Tri-State
Location: USA, North NJ, 07456
Vehicle:1998 Legacy 2.5GT Silver Sleeper BK, 5MT |
Quote:
Neither will a leakdown test. Sorry....... Any of those tests WILL check piston rings, will (to a point) check valve to valve seat contact. Valve stem seals are WAYYYYYYYY outside of any of these tests....... Unless, the engine is ready to blow up in spectacular fashion, even then, I HIGHLY doubt it...... Again......sorry for the disagreement...... Yet again, ducking the "ban hammer"...,,,,, PS, if you mean, "valve to valve seat" quality, then yes, I agree...... sorta what I stated, maybe just clarifying to others that "may" actually search....LOL...... A bad/poor valve to valve seat "wet test" is not particularly a good test......partly since the intake valves are up high and oil will likely not make any or much of a difference. Just saying...... |
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02-14-2018, 04:38 PM | #4 | |
Scooby Specialist
Member#: 459287
Join Date: Dec 2016
Chapter/Region:
VIC
Location: Vancouver BC Canada
Vehicle:1998 JDM Impreza STi V4 GF8 White |
Quote:
Which level is dropping... oil in the crankcase, or coolant? If it's neither, then it's just condensation burning off. |
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02-15-2018, 07:28 AM | #5 | |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
Quote:
The way I was looking at it is: - Compression Test - Dry Solid compression should mean all is good Low compression could mean bad rings/pistons/etc. Too soon to tell - Compression Test - Wet If compression comes back up to where it should be, in relation to the other good cylinders, then most likely a ring/piston issue If compression stays low, other problems exist. Start looking at valve issues, possibly in combination with ring/piston issues. |
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