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911 Oil Return Tube Replacement
 
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Pelican Technical Article:

911 Oil Return Tube Replacement

Time:

3-4 hours

Tab:

$29-$51

Talent:

***

Tools:

Metric socket and metric wrench set, oil catch pan, floor jack, jack stands, wheel chocks, needle nose pliers, vise grip pliers

Applicable Models:

 
Porsche 911 (1965-89)
Porsche 912 (1965-69)

Parts Required:

Replacement expandable oil return tube kit (order two in case you break the first one)

Performance Gain:

No more oil leaks

Complementary Modification:

Replace oil and oil filter
After recently installing a 2.7 911 motor in my 914-6, I took it out for a test drive. To my dismay, there were some significant oil leaks that I noticed when I pulled back into my garage. After looking at the engine from underneath, I couldn't really figure out clearly where they were coming from. Not wanting to think about it any more that day, I simply closed the garage, and decided to worry about it tomorrow.

The next day, I went out to my driveway to get my morning newspaper. Needless to say, I was astonished when I saw a long stream of oil coming from underneath the garage door. I opened the garage, and my garage floor looked like it would be a good candidate for an EPA Superfund clean-up site! There was a puddle of oil about 3 feet wide, and about six feet long, and it had somehow migrated underneath the garage door and down the driveway. This puddle is sadly shown in (Figure 1).

Seeing how there was so much oil there, I really couldn't easily figure out where it was all coming from. I originally thought that the oil was leaking from my oil tank lines. This line always has oil in it under slight pressure from the weight of the oil. I figured that this slow leak had to be from this line. I was wrong.

I didn't suspect the oil return tube at first, because I was most familiar with the 914 dry sump motor, which doesn't fill up the oil return tubes when the car is sitting idle. However, after consultation with a few other people, I soon learned that the oil return tube is often filled with oil when the car is sitting idle. The oil sump on the bottom of the 911 motor overflows into these tubes. If there is a small leak in one of the tubes, or past one of the seals, then you might find yourself losing oil at a tremendous rate overnight.

The purpose of these tubes is to return oil flow back to the sump at the bottom of the 911 motor. No oil flows through them at very high pressure. They simply collect the oil that flows back from the heads. The principle point of failure are the two seals on each end. After many years of service, the seals get old, and begin to leak, as shown in (Figure 2). The good news is that there is a relatively easy fix for these leaking tubes. Unlike the 914 oil return tubes, there are no pushrods running through them. To replace the oil return tubes with factory original ones, you need to take off the heads. However, there are replacement expandable tubes (Figure 3) that will allow you to replace a tube without even taking off the valve cover. This technical article will detail the process of removing the old tube and installing a new expandable tube.

The first step in beginning the replacement process is to make sure you've identified exactly where the leak is coming from. You would hate to do this job, and then figure out that the oil is coming from somewhere else. Before you begin, take your car to a self-serve car wash that allows you to wash your engine. Please don't wash the engine in the street, as this will hurt the environment. Drive the car back to your garage and immediately look underneath. You should be able to figure out exactly where all the oil is coming from. If it is coming from the oil return tube, then there will be oil on the ground right below the tube.

The next step is to empty the oil from the car. You don't absolutely need to empty the oil, but it will make the job a little bit neater. When you remove the oil return tube, a small stream of oil will run out, so make sure that you have a drip pan to catch the oil. Now, get the expandable oil return tube ready. Place the seals on both ends of the tube, lubricating them by dipping them in some fresh motor oil. Make sure that when you place the tube down, you place it on a clean cloth - you don't want to introduce any debris into your motor. After you have the two seals on the ends of the tube, place the two smaller seals on the inside of the push tube. These two seals prevent the tube from leaking within itself. You should lubricate these two seals as well. The tube should now resemble (Figure 4).

Now, push on the little circlip that comes with the tube. This rather large clip prevents the tube from coming apart when installed in your car. Use a pair of needle-nose pliers to make sure that you put the clip on without damaging both the clip or the tube, as shown in (Figure 5). Now, insert the smaller tube into the larger one. It should slide in quite easily. Note that if you are not careful while installing the tube, you can bend it, and then it will be almost impossible to expand when you're underneath the car. The assembled tube should now resemble (Figure 6).

Now, you need to remove the old tube. On some cars, you may need to remove the heat exchangers or headers to gain access to a particular oil return tube.  Be careful when pulling the heat exchangers off of the heads as you don't want to accidentally remove the head studs.  The best method for removing the oil return tube is to just take a pair of vise grips and crush the tube until it's bent. Then twist the tube with the vise grips until the tube comes out of one end, as shown in (Figure 7). If the seals are truly old, then the tube should come out easily. Once you get the tube out, if you didn't empty the oil out of the engine, it will begin to flow a little. Make sure that you have a drip pan ready. (Figure 8) shows the oil dripping out of the engine case where the tube used to attach to.

Insertion of the expandable tube is straightforward, although not too easy. Begin by placing one end of the tube into either the main engine case or the port nearest to the heads, as shown in (Figure 9). Depending upon your leverage, or your particular car, you will have to figure out which end is the best to start with. Make sure that you place the smaller end of the tube nearest to the heads. (the larger of the two tubes should go into the heads).  The reasoning behind this is that if the tubes are ever going to leak, they will probably leak worse when the engine is warm and the oil is hot and very thin. When the engine is running, the oil will be flowing from the heads to the main engine case. By placing the smaller tube within the bigger one, the oil flow will not press up against the seals. It's not a very big deal as to which way it goes in, but it may make a difference many years down the road when the seals begin to deteriorate.

After you have one side of the tube inserted into the case, then you need to expand the tube to reach the other side. There are a few ways of doing this, and none of them work too well. I would suggest holding one end of the tube lightly with a set of vise-grips, while pushing against one end of the tube with a screwdriver. Be careful while expanding the tube. If you damage it, then it will be almost impossible to expand the tube under the car. For this technical article, I ended up destroying the first one I had getting it in there. You might want to order two as cheap insurance. Once you remove the old one, you can't put it back in. It would be wise to have an extra tube on hand, so that your car is not sitting idle, waiting for one to be shipped next day air by Pelican Parts.

After you have the tube expanded and the seals are firmly mounted on both ends, then slide the circlip down until it reaches it's groove, securing it under the car. Use the needle-nose pliers again to avoid damaging the tube.

After you have installed the tube, check to make sure that everything is seated correctly. There should, of course, be no oil leaking out of the tube. After the tube is installed, then reinstall your heat exchangers or headers if you had to remove them to gain access. Use new copper exhaust gaskets between the heads and the pipes. Reinstall your muffler if you had to remove it too, using this opportunity to install new gaskets as well.

Well, that about sums it up. Hopefully  your car will no longer be leaking down the driveway. If you have any questions, feel free to ask.  Remember that Pelican Partscan provide you with all the parts that you need for any job!  Your continued support will guarantee that technical articles like this one will continue.  Please check out our ordering pagefor more information on our on-line catalog and on ordering new and used parts from us.

 


Bill Norwood adds:

Greetings,

I just finished installing new replacement oil return tubes on my 87 Targa as as per your bulletin. I replaced all without dropping the heat exchanger. In fact the one that seemed to be the hardest was the easiest. Rather than use a vise grip to get leverage on the slippery little devils, I put hose clamps on the ends of each. The hose clamps make great places on which to use a pry bar to gain the required leverage. The clamps don't damage the tubes and they come right off. A short handled expander tool for the C rings Helps too. Now if my creeper only had brakes.

Drivin' the Poorsche with thanks to Pelican Parts.

Bill Norwood  Gildedgallery@prodigy.net


JPF ( frickjp@theoffice.net) adds:

I saw your little tech session on replacing the oil return tubes on the 911. Nice touch, but I've found over the years two things that make life easier. Silicone paste instead of engine oil, Sil-Glyde from NAPA is cheap. The second is take that circlip and throw it out. I use gaiter spring from large Ford Spring-Lok A/C connections, available everywhere. Roll the gaiter spring up the tube, install it, slides righ in with Silicone paste for lube, and roll the gaiter spring into the groove with 1 finger. Beats the circlip method hands down. 4 tubes take about 15 extra minutes during an oil change.


Zakcruz@aol.com adds:

I just replaced my return tubes on my 84 911 using the tech article and the added suggestions from Bill and JPF.  I too replaced all 4 without removing the heat exchanger.  3 tubes were leaking, but I wanted a matching set.  First, I crushed the old tubes (1 at a time) and used tin snips to cut them.

This made it easier to remove especially the ones under the exchangers.  I used the Sil-Glyde.  I spent a little too much time looking for the gaiter spring from large Ford Spring-Lok A/C connect.  After visiting 4 auto-parts stores, Napa said they could get them the following morning but for $14 a piece.  I decided to go with the circlip.

The hose clamp suggestion worked great, although I only needed one clamp which I put on the thicker end which was the end that goes toward the crankcase.

The tool I could NOT have accomplished this with, is the expander tool.  At Ace Hardware, they sell a Snap Ring Plier Set for about $12.  It includes expander heads at a straight angle, 45 degrees and 90 degrees.  I used all 3 to move the circlip down the tube.  It almost seems like they made the set specifically for this job.

The job took me a 4 hours with trips to Ace for tools, but if I ever have to do it again, it should only take me about 45 minutes.  Not a drop of oil leaks from my car now.  Thanks everybody for the help.  Pelican rules!

 


Michael Carney adds:

My work [on a '93 C2] was in concert with a valve adjustment, and I found that the best approach requires the removal of the heat exchangers and the hard (36/32mm nuts) oil line. I found that with the return tubes preassembled to a length of 7.75 inches, that they would just fit between the head and case, ready for expansion. The hose clamps worked great, and I just lubed the seals with oil.

The one tool that made the job easiest, was the use of one of those ratcheting clamps (6 inch size), often used for woodworking projects. With one clamp end reversed, the clamp becomes a very strong spreader, which easily leverages against the hose clamps to expand the tubes.

I was fortunate not to have any of the stud problems with the removal of my exchangers, and while others have had success without this step, I believe it may be necessary to utilize the ratcheting clamp approach.





Huge oil leak
Figure 1

Huge Oil Leak

Original Leaking Oil Return Tube
Figure 2

Original Leaking Oil Return Tube

Expandable Oil Return Tube Kit
Figure 3

Expandable Oil Return Tube Kit

Two Pieces of Expandable Oil Return Tube
Figure 4

Two Pieces of Expandable Oil Return Tube

Placing Circlip on Tube
Figure 5

Placing Circlip on Tube

Assembled Expandable Oil Return Tube
Figure 6

Assembled Expandable Oil Return Tube

Removing Old Oil Return Tube
Figure 7

Removing Old Oil Return Tube

Oil Return Tube Removed
Figure 8

Oil Return Tube Removed

Inserting one-half of Tube into Engine Case
Figure 9

Inserting one-half of Tube into Engine Case

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Comments and Suggestions:
Peter Comments: I have a 87 911. Before I order parts, can you really do the left side oil return tubes without removing the heat exchanger? It looks almost impossible...
May 25, 2015
  Followup from the Pelican Staff: Almost impossible it is, but if you are patient, careful and lube the O-rings well you will be OK. - Casey at Pelican Parts  
N Number Comments: Im glad I did a good cleaning of the area before starting this tube replacement. Because it is not easy to keep the end O-rings clean. I tried mobil 1 oil and white lithium on the o rings and could just get the tubes to collapse and expand so I ended up getting the NAPA Sil-Glyde which made things slide much better. The hose clamps are a must for this job with heat exchangers in place. I taped the circlip in place with a screw driver.
March 3, 2015
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
radar54321 Comments: my oil reservoir gage is inop most of the time. what would be the steps to troubleshoot and repair? thnx for the oil tube info4.
can anyone help me?
May 21, 2012
  Followup from the Pelican Staff: Remove the gauge, connect a DVOM across the terminal, then move it and monitor for a resistance change. - Nick at Pelican Parts  
Tinker Comments: After giving this more thought, I really had no confideence in the garter spring method. The are too lightweight and with long term heat stress and vibration I am sure that they will fail and fall off, with disastrous results. Circlips just are not that difficult and went on fairly easily.....but you will need a couple of circlip pliers straight and angled. I replaced the tubes on my 84 911 in several hours. Drivers side heat exchangers obstructed much of the working area and these two took most of the time. Passenger side replacement took only 15 minutes for both. The use of temporary hose clamps at the end of each tube for leverage to work the large O-rings in works great and I recommend it.
March 30, 2010
  Followup from the Pelican Staff: Thanks for the input on this one. We appreciate the help.
- Nick at Pelican Parts
 
Tinker Comments: Wondering how many folks have used the garter springs instead of the circlips and if there is any experience with failures. I have the springs and can see that they would install really easily and be very secure but I am now wondering about their longevity due to heat and breaking off etc. Seems to me that could be a potentially really bad thing if it were to happen.....
March 26, 2010
  Followup from the Pelican Staff: I'm pasting your follow here. Great stuff:

After giving this more thought, I really had no confideence in the garter spring method. The are too lightweight and with long term heat stress and vibration I am sure that they will fail and fall off, with disastrous results. Circlips just are not that difficult and went on fairly easily.....but you will need a couple of circlip pliers straight and angled. I replaced the tubes on my 84 911 in several hours. Drivers side heat exchangers obstructed much of the working area and these two took most of the time. Passenger side replacement took only 15 minutes for both. The use of temporary hose clamps at the end of each tube for leverage to work the large O-rings in works great and I recommend it. - Nick at Pelican Parts
 
308cal Comments: Started with an oil leak about 6 months ago. Sense then I have park it and have not put her on the road sense. I replaced the valve cover gaskets and new oil plug washers. and oil lines. After filling her up with the correct 10 qts of 15w50 I cranked her and warm her up and took her for a spin. She ran great but noticed a couple of small problems. Oil level did not register and the Druck was not steady. So I park her and let her sit over night. The next morning to my disappointment was a puddle of oil, not a huge puddle but enough to warrant further investigation. I found the leak leading back to the Oil tubes. Today I removed the oil level float and the oil return tubes. Thanks to the trial and errors of others and their post I was able to remove the tubes without removing the heat exchangers. It was fairly easy to remove, instead of smashing and twisting the tubes I was able to cut them in half's using a Black and Decker sawzaw. Much easier. Waiting for the parts from Pelican to arrive this week to continue. I'll keep ya posted.
February 21, 2010
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
OLD GUY Comments: NO. 12 GARTER SPRING PARTS #'S SANTECH MT0089
TEM 207198

February 19, 2010
  Followup from the Pelican Staff: Thanks for the additional Info. We appreciate it.
- Nick at Pelican Parts
 
OLD GUY Comments: GARTER SPRING NOT GAITER SPRING !
February 18, 2010
  Followup from the Pelican Staff: Thanks for the input. - Nick at Pelican Parts  
Neel Comments: The part number for the gaiter spring in 4seasons is: FOU 24222. List is $.99 ea, my cost was $.78 ea. Any parts man worth his salt can cross reference them to your local brand. Who knows what the NAPA guy was thinking about.......
October 30, 2009
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 

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