70 GT Rear Main Seal Replacement/additive:
OpelGT.com is the premier Opel GT Forum on the internet. Registered Users do not see the above ads.
Thanks Thanks:  0
Likes Likes:  0
Dislikes Dislikes:  0
Results 1 to 17 of 17

Thread: 70 GT Rear Main Seal Replacement/additive:

  1. #1
    Opeler
    Join Date
    Mar 2007
    Location
    North Carolina
    Posts
    15
    Downloads
    0
    Uploads
    0

    Question70 GT Rear Main Seal Replacement/additive:

    Good morning:

    Can anyone tell me the procedure to replace the rear main seal in my 70 GT? 1.9 engine/4 spd. In some GM cars you can replace the seal without backing out the tranny. Leaks while engine is running. Pint a week.
    I don't think this is possible on a manual transmission. Is there any additive that would stop the oil leak? Any forums out there that could explain the procedure.

    Great site. Learning something new every day. Thanks to everyone.
    Ang
    Last edited by ameyer; 04-14-2011 at 12:29 PM.

  2. Remove Advertisements
    OpelGT.com
    Advertisements
     

  3. #2
    Mid-West Opeler sawdust's Avatar
    Join Date
    Oct 2006
    Location
    West Chicago, IL
    Posts
    2,390
    Real Name
    Hans
    Downloads
    0
    Uploads
    0
    How bad is the leak? A few drops a week? A quart a year?

    Buy a drip pan. Keep an eye on the oil level. Add as needed.

    I use STP oil treatment. Motor Honey. Every Oil change 3000 miles.
    Projekt 2019 - Der OPEL GT
    1971 Opel GT (Green) 10/28/06 VIN: 77 232 5469 Body U1032187 Build date: 10/70
    1972 Opel GT ..(Red) .05/11/07 VIN: 77 237 3202 Body U1049159 Build date: 11/71
    I am past the Age of knowing when I should know better

    Other Cars:
    2010 Fusion Hybrid (White)
    LINK to my picture Albums

  4. #3
    Project 1450 supporter... Site Supporter RallyBob's Avatar
    Join Date
    Mar 2002
    Location
    Spofford, NH
    Posts
    13,081
    Real Name
    Bob Legere
    Downloads
    0
    Uploads
    0
    Quote Originally Posted by ameyer View Post
    Good morning:

    Can anyone tell me the procedure to replace the rear main seal in my 70 GT? 1.9 engine/4 spd. In some GM cars you can replace the seal without backing out the tranny.
    I don't think this is possible on a manual transmission. Is there any additive that would stop the oil leak? Any forums out there that could explain the procedure.

    Great site. Learning something new every day. Thanks to everyone.
    Ang
    On the older GM cars with a 'rope seal' you can replace the seal without removing the tranny. Slow and tedious, but possible.

    Opels use a one-piece rubber rear main seal. Tranny must be removed, as well as the flywheel.

    FWIW, on my old 290,000-mile Nissan (which used to leak from everywhere), switching to 20w-50 'Brad Penn Racing' oil stopped all the leaking, and even dropped the oil burning by 2/3rds.
    My Flickr photos.
    C.R.L. 9/22/69 - 12/8/99, J.M.L. 3/3/43 - 6/15/04, D.M.L. 9/19/50 - 6/23/10, E.G. Sauer 2/26/66 - 2/18/10

    '70 GT 'Bonnie', '71 Ascona 4-dr turbo - winter beater, '71 Ascona 4-dr 'Turd' - rallycar, '72 Ascona wagon - 'Red', '72 Manta - caged street car, '74 Manta Luxus - factory sunroof, '74 Manta ITB racecar, '75 Manta - racecar

  5. Remove Advertisements
    OpelGT.com
    Advertisements
     

  6. #4
    Opeler
    Join Date
    Mar 2007
    Location
    North Carolina
    Posts
    15
    Downloads
    0
    Uploads
    0

    Thanks. Ang

    Quote Originally Posted by RallyBob View Post
    On the older GM cars with a 'rope seal' you can replace the seal without removing the tranny. Slow and tedious, but possible.

    Opels use a one-piece rubber rear main seal. Tranny must be removed, as well as the flywheel.

    FWIW, on my old 290,000-mile Nissan (which used to leak from everywhere), switching to 20w-50 'Brad Penn Racing' oil stopped all the leaking, and even dropped the oil burning by 2/3rds.
    Thanks.
    Ang

  7. #5
    Opeler
    Join Date
    Mar 2007
    Location
    North Carolina
    Posts
    15
    Downloads
    0
    Uploads
    0
    Thank you.
    Ang

  8. #6
    1000 Post Club jlthunder's Avatar
    Join Date
    May 2003
    Location
    Salfordville, PA
    Posts
    4,097
    Real Name
    Jeff
    Downloads
    0
    Uploads
    0
    If this engine was rebuilt, some people forget to put a small dab of gasket sealer on the 5th main bearing(not on the actual bearing surface) but where it meets up with the block which extends outside of the pan. Mine leaked there. I dropped the pan, unbolted the main, put the dabs of sealer there and no more leak.

    If this is an unmolested engine, then I would say it is the rear main seal and you have to removed the trans.

    Good Luck.
    Last edited by hrcollinsjr; 04-14-2011 at 11:44 PM.
    1972 Opel GT, Owner since 1983
    2001 Saab 9-5 SE 3.0 Turbo V6 Weeeeeeeeeee!!!
    1973 GT, Parted out, R.I.P.
    1968 Kadett, Owner since 2006, Sold, 28 June 2008

  9. #7
    Living in the past opelnut10's Avatar
    Join Date
    Jan 2004
    Location
    Chesapeake, Virginia
    Posts
    2,240
    Real Name
    Lloyd
    Downloads
    0
    Uploads
    0

    Oil Leak

    Quote Originally Posted by jlthunder View Post
    If this engine was rebuilt, some people forget to put a small dab of gasket sealer on the 5th main bearing(not on the actual bearing surface) but where it meets up with the block which extends outside of the pan. Mine leaked there. I dropped the pan, unbolted the main, put the dabs of selaer there and no more leak.

    If this is an unmolested engine, then I would say it is the rear main seal and you have to removed the trans.

    Good Luck.
    First I would get under the car with a can of brake clean and clean the oil pan area then run the car and investigate that it is in fact the seal leaking.Check all the oil pan bolts to make sure they are snug. Next inspect around the gasket to make sure it is intact without any gaps. If you are not worried about how it looks, sometimes you can clean the rear of the pan around the seal and smear some high-temp Permatex gasket sealer in that area to help it, if it is the seal leaking then it will require dropping the trans & bellhousing, removing the flywheel, the pan and the rear main cap to fix it. No additive that I am aware of is going to stop it from leaking, thicker oil will slow it down but it will still leak.

  10. #8
    1000 Post Club jlthunder's Avatar
    Join Date
    May 2003
    Location
    Salfordville, PA
    Posts
    4,097
    Real Name
    Jeff
    Downloads
    0
    Uploads
    0
    Quote Originally Posted by opelnut10 View Post
    First I would get under the car with a can of brake clean and clean the oil pan area then run the car and investigate that it is in fact the seal leaking.Check all the oil pan bolts to make sure they are snug. Next inspect around the gasket to make sure it is intact without any gaps. If you are not worried about how it looks, sometimes you can clean the rear of the pan around the seal and smear some high-temp Permatex gasket sealer in that area to help it, if it is the seal leaking then it will require dropping the trans & bellhousing, removing the flywheel, the pan and the rear main cap to fix it. No additive that I am aware of is going to stop it from leaking, thicker oil will slow it down but it will still leak.
    Good advise.
    My engine was clean since it just came off a rebuild and my leak looked like a main seal. OGTS pointed me to the bearing cap solution and they were right. Start with the simple stuff first as mentioned above before tearing into a rear main seal.
    1972 Opel GT, Owner since 1983
    2001 Saab 9-5 SE 3.0 Turbo V6 Weeeeeeeeeee!!!
    1973 GT, Parted out, R.I.P.
    1968 Kadett, Owner since 2006, Sold, 28 June 2008

  11. #9
    Not So Newb Anymore
    Join Date
    Oct 2008
    Location
    Seabrook, Tx
    Posts
    342
    Real Name
    Larry
    Downloads
    0
    Uploads
    0
    Good grief this problem is too common. Mine leaks as well. I will be tearing into this soon. My engine has a fresh rebuild and the builder was advised about the bearing cap deal but it may have still been overlooked. My leak is pretty bad though. Which is very aggrevating. Drip drip drip when hot. Running right down the back of the oil pan.

  12. #10
    Pathologic Opeler opeldean's Avatar
    Join Date
    Apr 2003
    Location
    Overland Park KS
    Posts
    1,955
    Real Name
    Dean
    Downloads
    0
    Uploads
    0

    rear main seal replacement

    https://www.opelgt.com/forums/6a-engi...ebuild-25.html


    look at post 467 in the apprenticing thread. should help you on the main seal install. Its not that bad.mine leaked after the rebuild,so I had to replace it. I ruined 2 seals until I learned the easy way in this photo
    Attached Images Attached Images
    Celeste: 1917cc ,Getrag ,Big valves,ported,ISKY cam on solids,Opel forged rods,9.52 compression,total seal gapless,oil dam,RB gasket mod., DCOE side drafts,sprint,pertronix,SACHS clutch,OGTS & Kadette sway bars,no oil leaks. Big brakes. Avatars Photos Carlisle 2010 by Jennie V.Thank you's to Bruce Butler and Gabe Sanchez

    Driven twice to Carlisle 2,351 miles RT successfully, broke down on first trip

  13. #11
    Southern Red Neck BQS4's Avatar
    Join Date
    Mar 2002
    Location
    Snellville, GA
    Posts
    9,622
    Real Name
    Gene
    Downloads
    1
    Uploads
    0
    Quote Originally Posted by opeldean View Post
    https://www.opelgt.com/forums/6a-engi...ebuild-25.html


    look at post 467 in the apprenticing thread. should help you on the main seal install. Its not that bad.mine leaked after the rebuild,so I had to replace it. I ruined 2 seals until I learned the easy way in this photo
    Dean;
    Not to steal your thunder, but, you also need to explain that the "blue tool" you show in your install pics is the actual Opel tool, which is mine. I'm willing to send it out to those who might need it.
    "Yes, I do have a rifle rack in my Sportwagon"

  14. #12
    Pathologic Opeler opeldean's Avatar
    Join Date
    Apr 2003
    Location
    Overland Park KS
    Posts
    1,955
    Real Name
    Dean
    Downloads
    0
    Uploads
    0

    tap seal in..dont hammer it or you will bend it...

    Quote Originally Posted by OpelNewb View Post
    My engine has a fresh rebuild and the builder was advised about the bearing cap deal but it may have still been overlooked. My leak is pretty bad though. Which is very aggrevating. Drip drip drip when hot. Running right down the back of the oil pan.
    Mine leaked after the rebuild too..notice in my photo...I used black sealer on the outside seal. There are 2 spots you can leak that i am aware of....1- the metal to metal interface that jeff speaks of and 2- the outside surface of the seal itself...the seal is not hammered in...its a gentle tap..if you have to hammered it..it gets bent..the key is the plastic sleeve and lots of grease.

    PS; THANK YOU Gene for lending me your blue OPEL tool. Its a perfect fit.
    Celeste: 1917cc ,Getrag ,Big valves,ported,ISKY cam on solids,Opel forged rods,9.52 compression,total seal gapless,oil dam,RB gasket mod., DCOE side drafts,sprint,pertronix,SACHS clutch,OGTS & Kadette sway bars,no oil leaks. Big brakes. Avatars Photos Carlisle 2010 by Jennie V.Thank you's to Bruce Butler and Gabe Sanchez

    Driven twice to Carlisle 2,351 miles RT successfully, broke down on first trip

  15. #13
    3000 Post Club Site Supporter P.J. Romano's Avatar
    Join Date
    Aug 2006
    Location
    Goderich, Ontario Canada
    Posts
    3,504
    Real Name
    P.J.
    Downloads
    2
    Uploads
    0
    I have made rear seal installer of the scrap metal. It works great.
    Attached Images Attached Images

  16. #14
    Opeler Dan-MI's Avatar
    Join Date
    Mar 2005
    Location
    Michigan
    Posts
    188
    Downloads
    1
    Uploads
    0
    Why the overhead film? The pics show you cutting it down and leaving it. That does no harm? Does it improve the seal?

  17. #15
    Southern Red Neck BQS4's Avatar
    Join Date
    Mar 2002
    Location
    Snellville, GA
    Posts
    9,622
    Real Name
    Gene
    Downloads
    1
    Uploads
    0
    Quote Originally Posted by Dan-MI View Post
    Why the overhead film? The pics show you cutting it down and leaving it. That does no harm? Does it improve the seal?
    First, the "blue tool" you see him using is supposed to have a second piece to it. The second piece does what the film does, in that, it helps the actual seal go over the crankshaft surface while tapping the main body of the seal in place with the rest of the tool. I do not have the original second piece, but, Dean is smart enough to have figured a way around it. That is why, if you read the whole thread of Dean installing the seal, he destroyed two seals before getting the third one in. Now, the film, once you get the entire seal properly seated, gets removed. He didn't mention this as it should be obvious. Anyway, he trimmed the film down so it would fit inside the blue tool and allow him to tap the body of the seal into it's proper place.
    "Yes, I do have a rifle rack in my Sportwagon"

  18. #16
    OpelGT.com Übermoderator kwilford's Avatar
    Join Date
    Mar 2002
    Location
    Calgary, Alberta, Canada
    Posts
    5,515
    Real Name
    Keith Wilford
    Downloads
    5
    Uploads
    0
    Quote Originally Posted by BQS4 View Post
    First, the "blue tool" you see him using is supposed to have a second piece to it. The second piece does what the film does, in that, it helps the actual seal go over the crankshaft surface while tapping the main body of the seal in place with the rest of the tool. I do not have the original second piece, but, Dean is smart enough to have figured a way around it. That is why, if you read the whole thread of Dean installing the seal, he destroyed two seals before getting the third one in. Now, the film, once you get the entire seal properly seated, gets removed. He didn't mention this as it should be obvious. Anyway, he trimmed the film down so it would fit inside the blue tool and allow him to tap the body of the seal into it's proper place.
    I have the same "blue tool" seal installer, which is a special Kent-Moore tool ("Seal Installer" #J-22928-2) specifically designed to install the CIH rear seal. And mine also came minus the second part ("Oil Seal Seal Protector", #J-22928), which, by the photos shown in the 1971 FSM Figures 60-61 and 60-62 on page 60-45) , is a cone shaped piece that the seal is slid over first before it is driven into place over the crank journal. The cone ensures that the seal lip doesn't fold back as the seal is installed, as the lip MUST face inwards to form an effective seal. Dean has devised an ingenious method using the plastic film to form a cone. But care must be taken to ensure that the seal lip isn't folded back. I installed a new rear engine seal in my old '88 Prelude a few years ago when I installed a new clutch, and that seal was even larger than the Opel CIH seal, so it was quite tricky to install without folding the lip back. The film would have done the trick. Good tip Dean!
    Attached Images Attached Images
    Last edited by kwilford; 06-19-2011 at 12:50 AM.
    Keith Wilford
    Finishing up a bare-metal, nut & bolt rotisserie restoration of my '71 Opel GT

  19. #17
    1000 Post Club zippy7575's Avatar
    Join Date
    Apr 2010
    Location
    Arizona
    Posts
    1,375
    Real Name
    Cam
    Downloads
    1
    Uploads
    0
    There's something to be said for making sure your rebuilder is experienced with Opel engines. I did a rebuild about 30 years ago via a local mechanic and the rear main seal leaked like a sieve thereafter. I put up with it for about ten years then finally bought a rebuilt 2.0L short-block from C&R Small Cars, which has worked perfectly for about 20 years now. Not sure if OGTS sells short blocks, but if so, that's what I'd do if I had to do a rebuild again.
    Sunburst yellow 1970 GT, 2.0L w/ header, Tremec T5, Weber 32/36, Pertronix, Sway Bars, BWA Sportstar wheels. Owned since 1973.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

    Similar Threads

    1. replacing the rear main seal
      By billiard13 in forum Opel Tips & Tricks
      Replies: 20
      Last Post: 04-01-2015, 12:17 AM
    2. rear main seal
      By opelgtboy70 in forum 6A - Engine Mechanical
      Replies: 23
      Last Post: 04-04-2007, 06:12 PM
    3. Warning: be gentle installing rear main seal
      By Beeger in forum 6A - Engine Mechanical
      Replies: 4
      Last Post: 07-13-2006, 10:17 AM
    4. rear main seal
      By Scott McDonald in forum 6A - Engine Mechanical
      Replies: 0
      Last Post: 04-13-2004, 11:36 AM
    5. Seal Rear Main Bearing Cap
      By N61WP in forum 6A - Engine Mechanical
      Replies: 1
      Last Post: 03-11-2003, 10:35 AM

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •