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Discussion Starter #1
I have a Nissan Xterra 2000 SE. After driving for a bit, then stopping, a small amount of white smoke with a burnt odor comes from under the hood briefly. It doesn't seem to be a serious issue, as the oil level isn't dropping fast enough to require supplemental fills between regular oil changes. But I'd rather not have a smoking, smelly vehicle.

So I've had my mechanic check it out when brought in for other repairs. He claims it's oil spilled from repairs burning off, and that it should go away soon. And has been claiming this for several years now.

Today I was able to determine the general area from where the smoke comes. Picture taken from the passenger side of the engine compartment:



I'm no auto mechanic, but something obviously isn't right. There's an oily area here. Most of it's dirty, but at the point marked with A I see some clean amber oil, so I'm guessing this is an active leak. I couldn't see any oil flowing. Perhaps it leaks only when the engine is revved, then periodically drips onto something hot.

B marks a screw mounted in a round rubber gasket. Although it may be hard to see from the photo, this gasket is deformed and oval compared to the others installed around the valve cover (I think that's what it's called), where the gaskets are perfectly round. Except of course at mark C, where the gasket is off the screw entirely!

I'm imagining two scenarios:

1) Oil is leaking strictly from around these faulty screw gaskets. They're damaged or improperly installed, and by just replacing them this could be inexpensively fixed.

2) The gaskets are like this because someone deliberately over-tightened them, in an attempt to solve a larger leak in the main valve cover gasket. And to fix it properly, a more expensive and complex repair would be needed.

But I really don't know. What do you folks think? I'd like to arm myself with a little knowledge before my next mechanic visit - which may well be a different mechanic, depending on what's going on here.
 

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I can't see that picture for some reason but it sounds like it could be you valve cover gasket.
The screws may just be loose or the gasket is worn out.
 

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Yep looks like you got a valve cover gasket leak that is dripping down and probably burning off on your exhaust manifold. Would highly suggest you have the gasket (and screw grommets) replaced since that leak usually leads to: destroying the starter from dripping down the back of the motor, or cracking your exhaust manifolds from the oil burning off on it.

The passenger side gasket is easy to do yourself. The driver side is a bit more difficult since you have to remove the intake manifold which is a huge PITA when doing it for the first time.
 

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Discussion Starter #5
Thank you all!

I looked up some more info based on your verifications of the issue. The repair looks reasonably easy for someone like me with basic, non-automotive mechanical skills. Can someone verify my understanding of this repair, I'd hate to be surprised by something partway through:

1) Purchase replacement valve cover gasket and (9) grommets.
2) Disconnect air/vacuum hoses from valve cover. Disconnect plenum/wires over cover. Optionally, disconnect fuel line if extra working space is needed.
3) Rock valve cover by hand, or whack with a rubber mallet, until it breaks free.
4) Scrape off old gasket, being careful not to gouge aluminum. Clean mating surfaces with solvent.
5) Apply new gasket to valve cover. Liquid sealant generally not necessary, it has tabs to hold it in place. If there's any obvious scratches or defects the gasket may not seal, apply a bit of supplemental black RTV silicone.
6) Replace valve cover, trying to lower it straight down, and making sure holes are properly aligned.
7) Apply a bit of red threadlocker to all screw threads. Get all screws/grommets in place, then tighten in alternating pattern, no need to torque down.

Anything missing, or that I should be aware of?
 

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Thank you all!

I looked up some more info based on your verifications of the issue. The repair looks reasonably easy for someone like me with basic, non-automotive mechanical skills. Can someone verify my understanding of this repair, I'd hate to be surprised by something partway through:

1) Purchase replacement valve cover gasket and (9) grommets.
2) Disconnect air/vacuum hoses from valve cover. Disconnect plenum/wires over cover. Optionally, disconnect fuel line if extra working space is needed.
3) Rock valve cover by hand, or whack with a rubber mallet, until it breaks free.
4) Scrape off old gasket, being careful not to gouge aluminum. Clean mating surfaces with solvent.
5) Apply new gasket to valve cover. Liquid sealant generally not necessary, it has tabs to hold it in place. If there's any obvious scratches or defects the gasket may not seal, apply a bit of supplemental black RTV silicone.
6) Replace valve cover, trying to lower it straight down, and making sure holes are properly aligned.
7) Apply a bit of red threadlocker to all screw threads. Get all screws/grommets in place, then tighten in alternating pattern, no need to torque down.

Anything missing, or that I should be aware of?
No sealant any were it is not necessary do not hit the covers they will come right off .No lock tight on screws . Make sure the grommets are installed rubber side up . Yes torque and again after warm up.You are going to need the 2 water hoses in the back with new clamps .Here a link to How to
http://www.clubxterra.org/forums/showthread.php?t=27722
 

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If you're doing the driver's side as well and removing the intake plenum, I would suggest cutting those two back hoses (have someone lift the plenum up while you go under it with snips) instead of trying to pry them off. Mine were basically fused on and its pretty hard to get your hands or a tool back there. Much easier to pry off the half a hose when the plenum is off. You can get replacement hose from autozone and cut to size or get the exact hoses from the dealer.

Most of your coolant will spill out when you cut those hoses so would be a good time to do a complete coolant change.

Also, definitely do your #6 spark plug while the plenum is off.
 

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Discussion Starter #8
Thanks [dejablue], that's a much more complete guide than what I'd pieced together. I will follow it and your recommendations.

I have a decent socket set, but not a torque wrench. Will this one work, adjustable from 20-200 in/lbs?



Or if not, an alternate recommendation, preferably around $50 or less? (Remember for me, this may be a tool I'll use only once or twice.)

[packpride85], I'm not planning on doing the driver's side, I admit that exceeds my current comfort level! Normally I don't work on vehicles, but am starting to do some selective DIY to keep maintenance costs reasonable. I will at least inspect the area for leakage. Spark plugs were professionally replaced this year, and coolant looks good.
 

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Thanks [dejablue], that's a much more complete guide than what I'd pieced together. I will follow it and your recommendations.

I have a decent socket set, but not a torque wrench. Will this one work, adjustable from 20-200 in/lbs?

http://www.amazon.com/TEKTON-24320-4-Inch-Torque-20-200-Inch/dp/B00C5ZL2EG/ref=sr_1_17?ie=UTF8&qid=1448560796&sr=8-17&keywords=torque+screwdriver


Or if not, an alternate recommendation, preferably around $50 or less? (Remember for me, this may be a tool I'll use only once or twice.)

[packpride85], I'm not planning on doing the driver's side, I admit that exceeds my current comfort level! Normally I don't work on vehicles, but am starting to do some selective DIY to keep maintenance costs reasonable. I will at least inspect the area for leakage. Spark plugs were professionally replaced this year, and coolant looks good.
Yes that will work the drivers side is not that bad just plan a Sat and Sun take your time and you can do it . no special tools need . Take some fotos of your bad gaskets to help others.
 
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