Gurgen: My buddy with a WRX just had the same situation and as Gzoom and Cook has pointed out it was from a bad seal on the turbo. The oil used to cool the turbo was getting in the exhaust stream. He was getting that same whiteish, blueish smoke and it was only happening when taking off from a stop and when revving in neutral. I confimred this when I was following him around town to see when the smoke was coming out. Have you replaced the PCV valve yet? That would be the cheapest of the fixes. Not sure how hard it is to replace that on our VQ35. Your turbos should still be under warranty right? Have you done a leakdown test yet to make sure you valve seals are okay?

04' G35S 6MT Ivory Pearl, Willow, Premium
Z-Tube / NFC Y-Pipe / Custom Mid-Pipe / 350 EVO Rear Sway/ '03 350Z Shocks and Springs

 

Oil anywhere in the exhaust system can easily cause the dense smoke you are describing, but it could also be originating from within the engine.

CHECK YOUR SPARK PLUGS!

If you are burning a considerable amount of motor oil in the engine it will reveal itself on the spark plugs. If possible, run your engine untill it is pumping out heavy smoke, quickly shut off the engine and remove all the plugs one by one and take note of which (if any) are corrupted with burned oil. This may help you isolate the ploblem to specific cylinders.



In Theory, practice and theory are the same.
In Practice, practice and theory are not the same.

2004 G35 6MT Blk/Blk Sedan Stillen Air, Stillen Exhaust

 

Check your turbo(s) shaft play. Turbos are extremely dependent on oil. Taking off the turbo can lead to just enough oul starvation to deteriorate the bearings. The last turbo I had on my 240 took a dive on me 2 months after I got it. I took it off to replace a wastegate gasket and didn't think I needed to prime it as much as I should have. It's a good idea to turn over the motor with the injectors orfuel pump disconnected so that you get get oil primed through the supply lines before actually starting the motor. Too bad I didn't know this until after my 3rd turbo.

If it happens after coasting, that's your compressor seal. During coasting you get vacuum in the intake pipes and the pressure differential from the oil side and the air side of the seal becomes great. Especially during higher RPM coasting where oil pressure is higher. If you remove your intake pipe, you'll probably see a nasty layer of oil coated in the pipes. This usually doesn't show up on your plugs either as it burns itself off before you can pull the plugs. And it's also spread out over all the cylinders rather than a single cylinder burning enough oil to see out of the tailpipe..

 

Hydrazine...

The plugs do have carbon deposits, just like my previous plugs by the end of their life cycle. I imagine that I will be switching these out pretty soon. They are 1 step colder plugs, which would foul more easily.

Ckwik...

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If it happens after coasting, that's your compressor seal. During coasting you get vacuum in the intake pipes and the pressure differential from the oil side and the air side of the seal becomes great. Especially during higher RPM coasting where oil pressure is higher. If you remove your intake pipe, you'll probably see a nasty layer of oil coated in the pipes.

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My findings are as follows... I took off the right side charge tube (not the left though) as well as the top plenum. Each had a very clean surface, with the charge tube having just a little oil in the rubber linkage (see below). The plenum was EXCEPTIONALLY clean, no trace of oil AT ALL.

Here is the pre-throttle body tube: IS this too much oil?



With this in mind, is it possible that the compressor side seal is bad?
Also, in general, if the leak is on the exhaust side, wouldn't the car smoke all the time, or at least during high boost runs where the exhaust gas temps are highest?

Thanks very much for your input...

Gurgen

 

Oh as far as priming is concerned... I do not know if he did it... However, given that these ball bearing turbos and require far less oil than sleeve-type turbos... I would think that priming may not be as essential... I am guessing here...

G

 

I think it's your compressor seal. That's about what my charge tube looked like on the RX7 when I had to replace the turbos, plus same smoking characteristics as your car, too. Hopefully they are still under warranty!

 

As to why your car does not smoke during "high rpm/heat/load" - it has been my experience that turbo seal oil leakage creates smoke after idling or after coasting to a stop. Pray that a policeman does not end up behind you at a long red light! The heat difference causes the seal at the exhaust side of a turbo to fail before the intake side fails. Cruising at highway speeds does not seem to produce much smoke unless you let off the gas and then accelerate. Smoke is produced when oil is partially burned. Temperature and oxygen content of the exhaust gas determines whether the oil is completely burned or not.

As a side light it is interesting to note that a car with a bad turbo seal will pass California smog with flying colors despite laying down a smoke screen like a destroyer. Exhaust soot will contaminate engine oil. I recommend turbocharged engines have their oil changed every 2,500 miles. Seal failure will cause increased oil contamination. How is the color of your oil?

G_Zoom

2004 Sedan 6MT, pearl white - willow

 

G-Zoom
Yeah that's what I was fearing..... Is there a definitive way to tell if the turbo is bad... (carbon deposits in the pre-downpipe, etc.)

Damn it... I am getting sick of this. This really sucks. My darn luck. The turbo goes afte rabout 3000 miles on the kit. The oil does not look very bad at all... A little black, but lighter/cleaner than my oil used to be before the turbos....

<P ID="edit"><FONT class="small"><EM>Edited by gurgenpb on 09/03/04 11:41 PM.</EM></FONT></P>

 

This TRULY sucks...... No, I have NO warranty!!!!! Anyone want a kidney?...

 

Oil in the charge pipe is a very good sign of oil leaking past the seal. Check the shaft play of the turbo though. If the play is within spec, then it may be too much oil pressure in which case you may only need to lower the oil pressure to the turbo. But I doubt this is the problem as it likely would have been a problem before. If there is excess shaft play, the bearings have gone bad. Seals rarely go bad by themselves. Usually a bearing failure causes seals to fail. Too much oil pressure doesn't cause seal failures, it's just beyond the limits of the seal's ability to hold the oil in. In this case, if you lower the pressure, it should stop oil from leaking past the seals. If the bearings are indeed bad, I'd recommend replacing the turbo(s). Rebuilds tend not to be very good from some turbo gurus I've talked to.

As for priming, I like to play it safe. My very first turbo on the 240 took a crap a week after putting on the kit. I apparently didn't tighten the oil supply line enough and oil leaked all over when I first started it. It seemed fine, but the bearings gave a week into it. The replacement turbo was brand new and lasted some time, but I had removed it several times to fix small issues. I didn't prime it at all each time. It eventually developed similar symptoms to what you are having now. My last turbo was actually supposed to be a rebuild. Once they had my turbo apart, they determined none of the CHRA components were any good. They replaced all the parts except the compressor and turbine housings. It worked fine until I removed it once. I neglected to prime it yet again. Less than a month later it started to smoke. Keep in mind while the components in the last turbo were new, the whole thing was pieced together by the rebuilder. Next time I buy a turbo, it will be a brand new assembly built by a reputable builder. I'm sure it would have been fine if I primed it the second time around, but it still should not have gone out that quickly. I traded that car in for the G before I had the chance to make everything right. I'd love to turbo the G, but I'll need to wait until I make some more money first. Though the G is plenty fun to drive even without a turbo.

 

For a while I was able to keep the car from smoking at a stop by keeping the A/C on(higher idle). I did get pulled over once and left a huge cloud of smoke for the cop as I left. Either he didn't see it or didn't care.

As an additonal note, if you drive around like this, keep an eye on the oil level and make sure it doesn't drop too far. At it's highest consumption, my 240 required a quart about every two weeks.

 

Gurgen,

Do you still have your TT kit?? I thought you were going to build a new engine. Is Street Image going to build you a new engine??

 

By the way, thanks for the recommendation on Street Image. They did an excellent job on my bodykit installation. Eric is really professional, maticulous, and methodical about installation. Really a friendly guy to work with. Again, thanks a bunch Gurgen.

 

It has been my experience that the turbo seals fail before the bearing. As long as oil keeps flowing, the bearing should be fine. Keeping oil in the bearing is most critical. If you plan to keep the turbos, I would find a specialty turbo rebuilding shop. I would shop the internet and find one that has been around for a long time. You can UPS the turbos to the shop. The bearing and the seals will be replaced. I suspect it might cost a few hundred dollars apiece.

Here are a few hints to help improve the longevity of your turbos. I ran mine for 24 years and 100,000 miles before it failed.

1. Get the turbos water-cooled as to carry away heat that might boil off the oil after turning off the engine.

2. Let the engine cool down after any high rpm/load/heat run before turning off the engine. If turned off right away, the oil in the bearing will boil off. Truckers have learned this.

3 After changing the oil, "prime" the oil system by cranking the engine without the engine starting. This will fill up the thimble-sized oil filter we have. I used to disconnect the primary from the coil. I am not sure how to cut off the fuel from the G35. I am sure someone knows.

4. Becuase of normal oil contamination with a turbo, change the engine oil every 2,500 miles. I wonder if slightly heavier weight oil might leave a better coating on the bearing after sitting for a time. There is a new Castrol oil out that is supposed to stick to parts and not run off. I would run full engine oil pressure to the bearing.

High horsepower without a turbo is one reason I bought the G35. I have a friend who wants to unload his very nice S4 2.7 liter biturbo before seal failure costs him a king's ransom. Any takers?

G_Zoom

2004 Sedan 6MT, pearl white - willow

 

WRT a stem seal, I don't mean to imply that a seal "is" what's wrong, but similarly the leak sounds to be in the "intake" tract, since oil seems to get sucked in during a vaccum (off throttle) cycle. Most likely the turbo seals as mentioned by others.

Note: when a valve stem seal leaks "at most" it may "raise" your leak down compression some since a little oil temporarily improves ring sealing.