Attention: Dipstick Guide Tube N62
 

As you know, this past summer I tackled the valve stem seals. While doing this, I had to tackle quite a few other jobs - because "I was in there"

While doing the job, I had an issue with my dipstick guide tube, and I thought it was just me. Now, after the dust has settled, another member - Johnny_5 - has the same issue with the dipstick guide I had, and he thinks that this might be another cause of the smoking issue.

Here is the issue nobody mentioned a thing about it.

The dipstick guide tube for the N62 engine is made out of 2 tubes: a lower & upper tube. They mate together just below the VCG level. The lower dipstick guide has some sort of a plastic guide where the upper dipstick guide mates. When doing the VCG, one has the tendency to push the dipstick away, rather hard. I know I did.

What nobody tells you, is the fact that that plastic nipple will degrade in time and will break. Mine disintegrated like chewing gum. Also, when tackling the VCG, one should ROTATE the upper guide very GENTLY. I know this now, after the lower guide was wrecked. My contribution was being probably a bit hard on it when pushing it aside (instead of rotating it).

If that nipple/guide breaks, You're in for a new lower dipstick guide, which is a royal PITA to change. Here is what you need to do, in case it breaks:

• remove the oil from the engine (if not, about 4 qts will gush out)
• remove the engine beauty cover (probably done, because you did a VCG, or similar, and now you found yourself with 1/2 of a dipstick in your hand)
• remove lower plastic belly cover
• remove reinforcement plate
• remove 10mm bolt that holds lower dipstick below VCG level
• Now comes the fun part - removing the dipstick (lower).

here's what you have to do: get a few good light sources. The space is very restrictive. Get a small ratchet - this is a specialty tool. You need a ratchet with a very short handle (like stubby), otherwise it WON'T fit in there. You need a small clean mirror.
Now study the layout. Very carefully. Then, get your hands and by feel see how you can remove the 8mm nylock that holds the plate, which in turn secures the lower dipstick. You have either visual, but you can't work, or you lose visual, but now your hands are in there. Very, very tight, but doable. Once the 8mm nylock is out, the lower dipstick can be removed.

Below the plate that holds the dipstick is a thick aluminum securing washer. Inside the oil pan guide where the dipstick stays, is the O-ring. Make sure you don't lose the washer. If you plan on changing the O-ring, the lower oil pan has to come out, otherwise you will NEVER replace that O-ring. It's pretty hard to remove it, and to install it back on is even harder. You cannot install it the "traditional" way - by mounting it on the dipstick and wedge it in there. The guide of the oil pan has minimal clearance for the dipstick guide, it has a groove where the O-ring seats, and if mounted on the dipstick, it will never get squished in that small orifice to be pushed in the groove.

Maybe someone will realize this lower dipstick design shortcoming and will build a better one? A new one will last only as long as the old one - the plastic will deteriorate after so many hot/cold cycles. This post is mainly a FYI, in case one does the VCG and wonders why the dipstick is so sloppy. here's the realoem sketch (P.S.: the realoem sketch does NOT show the nipple on the lower dipstick guide - the one that breaks):

http://realoem.com/bmw/diagrams/r/z/194.png

God and I thought installing my cold weather version dipstick guide tube for my M54 when I did the CCV was tough enough.

Another reason to be happy not to have a V8.

I just found out myself that the bottom tube contact to the upper tube is broken off and the top half was silicone on so trying to tackle this replacement myself but with limited space in the garage. Knowing how much of a pain this was going to be I would have just left the X outside!!! Pretty dumb design where you have to remove the oil just to remove a damn dipstick tube!

How does the upper guide come off?

I see a part for an o-ring as well.

I noticed the bottom half of the dip stick was caked in oil so I'm thinking it's leaking where it joins together.

Also a failed connection between the upper and lower guide tube cause a vacuum leak?

There should be a 14mm screw attached to the cylinder head for the upper half. I don't recall exactly how it comes a part but I may still have the old dip stick tube so Ill see if I can remember how I did it. Not sure if I removed the entire dip stick or if I was able to just remove the upper half. Give me a few days and Ill see if I still have the old setup.

The o-ring that meets the bottom half to the upper half if that fails would it cause an oil leak? Does the oil travel up that far when crankcase is pressurized?

I noticed while doing other stuff down there only the bottom half of the tube was wet with oil.

If your talking about oring at the bottom near the pan yes. If your talking about the middle joining piece no. It’s possible it could be the valve cover gasket.