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Old 03-18-2019, 11:42 AM
Baby Unicorn Taco Baby Unicorn Taco is offline
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Location: Charleston, SC
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Quote:
Originally Posted by Westlotorn View Post
Glad you got yours fixed. Aren't these x5's fun to work on! Great car, not easy to work on.

The FIRST thing to check for anyone considering this job is the vent hoses where they enter the front of your intake manifold by the throttle body. A vent hose comes from each valve cover, these hoses on my 08 4.8L meet in the middle at a T and one hose connects to the Intake Manifold. Pull this hose and inspect. If OIL is in this hose and you see oil inside your intake when you shine a pen light into the connection for this hose you have a Vacuum leak. Nothing else will put oil into these hoses or the manifold. Nothing. You would see a minor amount of oil from the vapor in the hoses but no running or dripping oil in a good engine.
The fact that your car had stinky exhaust for 100 miles indicates your manifold probably had residual oil in it and most of it cleaned up over time.
With a reduced amount of oil coming in your Cats would have burned it up giving you clean looking exhaust. A greater amount would smoke out the back.
Even with the manifold off the car it is hard to wash all the oil out.
I think I washed mine with Diesel fuel first and then hot soapy water before putting it back on.
With the Manifold off the car you can inspect the Intake Valves, they should be clean and pretty dry, if a valve stem seal has been leaking enough to make the engine smoke you will see wet oil on the intake valve heads looking down the intake ports.
If the oil is coming down from the manifold rather than the valve stem seal you will see the oil path going down the intake ports. The should be clean aluminum.
You are correct that while in there, installing new valve stem seals is not that much more work or expense over doing just the gaskets.
I have only fixed 3 of these, a 4.4, 4.6 and my current 4.8L, have not needed valve stem seals yet. One was repaired at 140K and is now over 200,000 miles.
The 4.8L is only at 115,000 after being repaired at 90K, no longer leaks or burns oil.

The best side effect was how well the tranny shifts once the air leaks are plugged.
It shifts like brand new again. If your throttle is a little jumpy coming off idle in first gear that is an indicator.
^ This is a good paragraph of information for anyone first trying to figure out their N62 oil/smoke issues. Someone could search multiple threads for hours trying to find what Westlotorn just stated. Simple, to the point, Well said.
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