Engine Rear main seal

Discussion in '3rd Gen 1997-2002 2.0L SOHC' started by Gamer92, Jan 12, 2017.

  1. Gamer92

    Gamer92 FEOA Donator

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    So after my last rebuild back in early 2016 I noticed after getting the engine back in car and driving it for a bit i had a slight oil leak between engine and trans mating surfaces on the bottom.

    Fast forward to last week the area is soaked with oil and today I noticed a significant drop.


    I recall having a difficult time installing the seal with the holder already bolted to the block.

    So, is the seal easier to install with the holder on the block or is it easier to install the holder with the seal?
  2. 04Svt

    04Svt FEOA Member

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    It's funny this came up but I had the same problem when I rebuilt the engine in my 2000 . I had the same leak..it wouldn't leak when it was cold but as soon as the engine got warm it would leak. So I tore the engine back out and took the flex plate off. I had the engine on my crane at a angle and noticed oil was dumping out of the crank shaft bolt holes. I'm like wtf?? It wasn't the rear main seal that I had suspected as well. The crank was drilled all the way through and the oil was seeping through the bolt threads when the engine warmed up. My fix worked ..I got some ultra gray rtv and squeeze a bunch in the bolt threads. Also put some on the bolts before installing them back in with the flex plate. Installed the engine..waited a day for the rtv to dry and it never leaked a drop in that area again.

    Hope this helps
  3. Gamer92

    Gamer92 FEOA Donator

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    Are you referring to the bolts that holds the rear seal carrier?
  4. 04Svt

    04Svt FEOA Member

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    No , ford drilled the crank all the way through the crank shaft .
    It happened to me that's how I know..your gonna have to pull the motor again to fix the leak.
  5. Gamer92

    Gamer92 FEOA Donator

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    The only bolts on that end of the crank are for the flex plate. Are you referring to those?
  6. 04Svt

    04Svt FEOA Member

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    Yes.
    I've built many engines and never seen this until the escort motor.
    Usually they stop halfway then tap it for threads.
  7. denisond3

    denisond3 Moderator Staff Member

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    The Ford Service Manuals mention using some kind of a sealant on the threads of the six bolts that hold the flywheel (or flexplate) to the flange on the crankshaft....and that those holes go all the way through the flange. So when the engine is running, the bottom of the threaded holes are facing the crankcase oil tornado. I use Permatex Ultra Black on the threads; so far it has kept the leaks to a minimum or zero. A thread-locker coating might work as well, like the 'green' or 'blue' – Not the 'red'.

    If it was me, I would likely endure the leak with a car having an automatic transmission; until I had some other reason to separate trans from engine. With a 5-speed though, the oil leaking into the clutch area is likely to cause grief – either shuddering or slipping.

    I prefer to install the rear main seal into the holder first, the install the holder with the seal in it, and the paper gasket of course. To get the lip of the seal over the crankshaft flange (without the inside spring coming out) I use a feeler gauge (about .004") to slide around the circumference of the seal as I urge the seal holder to go further on with my other hand. I used crocus cloth to polish the sides and tip of the feeler gauge. They make a tool like this to help get the lips of the seals in the automatic transmission clutch packs to slide down into place.


    The rear main seal holders on my 2nd gen Escorts have little locating tabs, so you cant go too far off when putting the seal/holder on.
    Pizzaman5000 likes this.
  8. 04Svt

    04Svt FEOA Member

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    I wouldn't use the loc tight..I used it like always and it leaked really bad.
    When I took the engine back out I used ultra grey high temperature rtv.
    No leaks at all.
    denisond3 likes this.
  9. denisond3

    denisond3 Moderator Staff Member

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    Thanks for the info. I understand the ultra grey high temp RTV is one that cures to be more like a solid. The Ultra Black stays somewhat flexible after curing, which makes it nice when scraping it from things like the intake manifold; but it seems to have good oil resistance.

    I know the RTV takes a long time to cure if its not where air can get to it, but Im such a slow worker that its usually more than a week or two after I bolt a flywheel or flex plate on, before the engine gets oil in the crankcase and started.
    I also toss out the tube of permatex RTV product once its been over 6-8 months since I opened it.
    Last edited: Jan 14, 2017
  10. pcordes1979

    pcordes1979 FEOA Member

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    This thread has been a good read, I have an engine I may be swapping the crankshaft on one of these days and provided some good information that I was unaware of.

    However, why not use Permatex's own white thread sealant? It is specifically designed to seal threads to prevent oil and other liquids from getting through while still being easy to disassemble as needed, whereas the RTV and thread locker are designed for other purposes like gasket making or preventing fasteners from loosening themselves? I use it on my oil pan drain plugs and never get a single drip.

    https://www.permatex.com/products/t...nts/permatex-high-temperature-thread-sealant/
  11. 04Svt

    04Svt FEOA Member

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    That might work but I would just use the ultra gray...usually when you build a motor your not removing the engine all the time to take the flex plate bolts out. So it shouldn't even matter about disassembly. Plus if you ever rebuilt it again I would just have the holes welded shut from the inside so it wouldn't be a problem. Who ever drilled the cranks probably got lazy and went to China drilling those holes.
  12. denisond3

    denisond3 Moderator Staff Member

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    Thank you for the tip pcordes1979! I didnt know they had a product like that.

    I think of welding anywhere on a crankshaft as something involving special equipment and skills. Much easier for me to slap on some sealant.
  13. 04Svt

    04Svt FEOA Member

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    Any competent engine machine shop could do it.
    That's what I will do after I get 2 or 300k out of my fresh rebuild.
  14. Gamer92

    Gamer92 FEOA Donator

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    So why does the rear part of the crankshaft get oil?
  15. 04Svt

    04Svt FEOA Member

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    Like why was oil getting to it and seeping? The crank should only be threaded about 3/4 of the way. Mine was drilled all the way through. I don't believe the oil goes as high as the crank but there is windage pressure in there so who knows..but oil will find a way out if it's possible.
  16. Gamer92

    Gamer92 FEOA Donator

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    Guess I'll have some fun and pull the trans out to fix this
  17. Gamer92

    Gamer92 FEOA Donator

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    Crank.jpg
    I understand now. For some reason I thought the piece that the seal rode on was sticking out more. I see how the oil can leak through the holes.


    I installed the bolts dry. Seems I'm paying for that now
  18. 04Svt

    04Svt FEOA Member

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    I would just pull the motor..you can have it out in like 2 hours.
    Much easier than the trans. I couldn't drop the transmission in mine. Seemed like not enough room for the auto.
    I got upset so just pulled motor with the trans. Lol
  19. 04Svt

    04Svt FEOA Member

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    I didn't pay attention either..like I said I've built lots of motors and none were drilled all the way through.
    Until this little car
  20. 04Svt

    04Svt FEOA Member

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    Like I said just squeeze some ultra gray in those threads ..no more worries.

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