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Thread: Oil Leaks

  1. #1

    Oil Leaks

    My newly purchased 73 911S has two oil leaks. When the engine is cleaned and left to sit overnight, there are two small leaks. One is directly below the center of the engine where it attaches to the trans. One is also at the center of the engine directly below the rear pulley. I suspect the front and rear seals since the car had not been driven much (5000 miles in the last ten years).
    My question is if the engine is removed, how hard is it to replace these seals? I've rebuilt engines before, but never worked on Porsches.
    Thanks for any suggestions.
    1973 911S
    1967 Alfa GTV
    2002 Miata

  2. #2
    It requires a special tool to reinstall the rear main and the main bearing seal that you are suggesting on the front (rear of the car) of the engine.
    Another leak source is the thermostat housing "O" Ring. Easy enough to replace on MFI or Carburetted cars. Not so easy on CSI cars. Check you pressure sender as well as they like to leak. The crankcase breather can leak as well. All of these can be handled in a matter of an hour or two.

    The rear main and main seal behind the pulley will take a day since you need to pull the engine and to do the rear main you have to remove the transmission and clutch assembly as well as the flywheel. It's not as awful as it sounds but it will try you if you are on your own. I suggest "pressing", pulling a Tom Sawyer or just plain begging for assistance from an able bodied person who can take instructions for the engine removal-reinstall.

    Good luck,

    "Be who you are and say what you feel because those who mind don't matter and those who matter don't mind." - Dr. Seuss
    "Experience is the mother of wisdom" - idiom
    "Let them that don't want none, have memories of not gettin' any"- Brother Dave Gardner

    Early S Registry #235
    rgruppe #111

  3. #3
    Before you pull the engine, make sure the leak source isn't from above. Gravity has a way of taking any leaks and depositing it on parts below it. Some likely culprits (from many possible) could be the oil temp. sender and, as Tom mentioned, the thermostat O-ring.


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