hyphenf15

I searched the archives with no luck. I have the 8 volume tech manuals in PDF format but I can't find any specific information about removal and installation of the oil return tubes. Can the tubes be removed and new seals installed without having to take the engine apart? There is an add from Weltmeister that says they can be removed and replaced without much work. Looking for advice again for my 96 C4. Thanks.

Rick Lee

I haven't done them on a 964, but have on other 911's and I think the jobs are similar. There is a chapter on this in Wayne Dempsey's 101 Projects for Your 911. Just use some channel locks and bend/break each tube and then pull them out. It's messy and not a pretty sight. If your engine has never been apart before, you will have the one-piece tubes. But unless you want to take your engine apart, you will need to replace them with the collapsable, two-piece tubes. You need some Slyglide or some silicone lube and new O-rings too. Basically, the collapsable tubes work like that plastic piece that goes through a roll of toilet paper. You collapse the tube to fit between the head and case and then expand it to make it go in each end. A circlip locks the two halves into place. But you probably won't be able to do it with just your hands. So the trick is to put a hose clamp on each end of the tube so you can grab onto it with channel locks and press each end in. The O-rings can make this require a lot of force. Whatever you do, make sure you get the correct O-rings. The wrong ones will go in too easily and leak. If it's difficult, you probably have the right ones. I can't remember if the right ones are green, black or orange.

hyphenf15

I do have the one piece tubes and don't want to take the engine apart at this time. Thanks for the info.

Rick Lee

You don't have to take the engine apart. Just buy the collapsable tubes and O-rings.

John D.

Yes... To remove them.....

Take some vise grips, and clamp them shut on as close to the middle of the return tube as possible. Twist, and they will collapse and you can turn them out.. That's the easy part....

To reinstall.....?? Get the collapsible tubes (non-collapsible require the cam-carriers be removed...)..!!!The left side rear is a bear, as there is NOT a lot of room... Anyway, get the tube set and pre-lube the seals. Next, attach two hose clamps near the outer ends of the collapsed tube. Put the tube into place, and working from the outer end and using the screw from the clamp - place the end into the camshaft carrier (outer end). You will feel it "slip" into place...

Next - still holding the outer end, now in the carrier - pry/work the inner end into the engine housing, again, using the second hose clamp as the leverage point to work it in...

After it is seated (or SO YOU THINK!!! ) recheck the seat on BOTH ends (or it will leak like a sieve sifting water).. Ask me how I know...

John

JasonAndreas

Don't bother with the aftermarket return tubes, buy genuine OE and get them from EBSRacing.com. You will need some Dow Corning 111 or 112 high performance silicone o-ring grease available from someone like McMaster-Carr, there is a night and day difference between using this stuff and engine oil as a lube. The biggest issue for me was removing the heat-exchangers. One nut was a pile of rust and one socket head nut was rounded so I melted/cut both with MAPP gas & oxygen. There was no room to get a dremel tool or bolt remover between the heat exchanger and the cylinder head. And don't forget to buy 8 size M8 all-metal locking nuts (#999-084-052-02) and 4 size M8 socket head nuts (#999-085-001-02) and 6 exhaust manifold gaskets (#993-111-195-00) if you remove the heat exchangers. The torque specification for the nuts is 28 Nm (21 ft-lbs).



Using the breeze clamp trick (that John & Rick described above) from Pelican made the job pretty easy. There is also another method involving a modified inverted clamp.

Their replacement is covered in the 964 Engine Workshop Manual Page 13-46 and there is a TSB for the 993, "Oil Return Tubes" from March 24, 1994 that says to use the same parts as the 964.

Mike J

Hi Jason,

I think I got my 111 from EBS. You are absolutely right, that stuff is way better than oil and the return tube O rings pop in with a little force with the lube on them. I have used the 111 on just about all O rings on the engine rebuild with zero leaks. Good advice!

Cheers,

Mike

hyphenf15

Awesome information. You guys rock!! thanks for the links an pictures.