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  1. #1
    FEP Senior Member BlackWatch's Avatar
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    Default Help diagnose an oil leak (w/pics)

    Hope you guys can help. I have an 85 GT all stock with 72000 orig miles on it. I am the second owner, first owner let it sit without starting for 14 years
    In 2010 he put it back on the road and put 4000 miles on it in 2 summers then I bought it.
    The rear main seal appears to have a small leak. I just had the valve cover gaskets replaced because they were leaking. I took the car on a 300 mile trip and then let it sit for a week. Yesterday I notice a large oil leak on the passenger side coming down from the motor mount. I have cardboard under it in the driveway to keep the small rear seal leak from spotting up the driveway.
    The bottom of the motor mount can be moved up and down and twisted around. I can't reach the other mount so not being a mechanic I have no idea if this is normal.
    The bottom of the valve cover does not appear to be leaking however, the oil is coming down and pooling in the motor mount and then running onto the sway bar and then hitting the ground.







    http://i375.photobucket.com/albums/o...aStorm/058.jpg
    I cleaned off all of the oil with spray 9 and water from this side of the engine, drove the car 10 miles and then this amount of oil leaked out in the first 30 minutes!
    Hopefully someone here can give me an idea or two. Thanks
    Last edited by BlackWatch; 06-23-2012 at 01:24 PM.

  2. #2
    FEP Super Member bwguardian's Avatar
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    ...well, my 85 sat for 16 years in covered storage and never started I probably could of primed it and started it up but chose to pull the engine and install new gaskets/seals, new oil pump, and new timing chain.

    I would look at the front and back of the intake manifold...on the block at the fire wall and at on the block at the distributor...and see if there is any oil there. More than likely it is this or a combination of the oil pan and front/rear main seal.

    Oh, you should not be able to move the engine mount with your hand. The rubber part of the mounts may be gone...especailly with the leaking oil on them. That was the other thing I replaced in mine. Keep in mind the vert engine mounts are stronger and sit a little lower if you ever decide to replace them.

    I do also recall the power steering rack leaking a little when I first moved it and got her up and running but it sealed back up. The power steering fluid has conditioners in it to help the seals swell and seal back up. I see this possibility in one of the pictures I see above. This brings me to something you might try...add a quart of ATF to the crank case and run it for 400-500 miles as it will condition the gaskets/seals.
    Last edited by bwguardian; 06-23-2012 at 02:46 PM.
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  3. #3
    FEP Senior Member BlackWatch's Avatar
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    Thanks, the leak was really bad for the first hour after I parked it. Then I turned the cardboard over to the clean side and in the past 4 hours there has only been 1 or 2 drops. So whatever it is, it seems to only happen when the engine has just been run?

  4. #4
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    It looks like the inside lip of the bellhousing cover thingy behind the rear oil drain plug is pretty. The cover looks pretty grimey and oily on the outer side toward the oil pan. Usually the inside lip is wet witn a rear main leak. Yours may be intake manifold or rear oil pan leak? I seem to recall a previous thread about this awesome product called ATP AT-205 ReSeal that you may consider.....

  5. #5
    FEP Member OX1's Avatar
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    Put the orange dye in the oil and get a cheap black light and yellow glasses.
    Worked great to determine my dads LTD leak, which was actually the rear section of oil pan gasket and not rear main seal like we first thought.
    86 Capri, single turbo, 3.27's-12.662 @ 107.75
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  6. #6
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    im a little confused by the the picture ,but i had an oil leak once and it ended up coming from the fuel pump . the gasket was leaking where it mounted on the motor dont know if that helps any or not

  7. #7

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    Quote Originally Posted by OX1 View Post
    Put the orange dye in the oil and get a cheap black light and yellow glasses.
    Worked great to determine my dads LTD leak, which was actually the rear section of oil pan gasket and not rear main seal like we first thought.
    +1.....the dye never lies! I would double check the rear oil pan bolts for sure. Thats an easy fix if it works. Oil can blow around alot too and gravity pulls it down. After you put the dye in, start high and work your way down.
    85 GT Vert' (CFI converted to EFI), 306 TFS 170's, Systemax II, Lunati cam, 8.8 w/3.73, Ford Racing T-5, AFM Powerpipe
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  8. #8
    FEP Senior Member BlackWatch's Avatar
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    Is it possible that the oil pan bolts may have come loose after some higher RPM driving, that the car hasn't seen since Reagan was in office
    The drain plug seems to be showing a drop of oil on it.

    What would make it leak oil for about 30 minutes after it was driven? After it cools down the leak almost goes away.

  9. #9

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    With that description, it would make me believe it leaks right after because the fresh movement of the oil gets going out the leaking location. Thus, when you shut it off the circulation stops and when pressure drops so does the leak. Its just hard to say...it could be alot of reasons. I would get the dye, all auto part stores stock it...its just a small vial sized tube that you put in the oil and run for a little bit. You can see it with flashlight and bare eye.
    85 GT Vert' (CFI converted to EFI), 306 TFS 170's, Systemax II, Lunati cam, 8.8 w/3.73, Ford Racing T-5, AFM Powerpipe
    317 rwhp 304 rwtq

  10. #10
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    Oil leaks suck. Seal technology must really be improved nowadays because my 2007 Tahoe which has 107K miles, more than my 86 GT has mind you, is dry as a bone underneath. We've driven that truck crosscountry. You cant find a late 80s or early 90s vehicke that doesnt leak from somewhere.

  11. #11
    FEP User vern2.3's Avatar
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    You had the valve cover gaskets changed, but is the leak coming from one of the new valve cover gaskets? Don't overlook a pinch on the new gasket on that side of the engine.

    Something else to think of: "What is the condition of the inside of the heads?"

    I bought a used '80 T-Bird with a 302 and had all the gaskets caskets & seals changed because of leaks. I went out of town for a month and left the Bird at the shop so they could pull the engine to change oil pan gaskets and the rear main seal.

    I got back from the vacation Uncle Sam sent me on and picked up what I expected to be a leak-free car. Still leaked like a seive around the valve cover gaskets and there were signs of oil getting into the air cleaner.

    I pulled the valve covers myself and found the inside of the heads so gummed up the oil could not drain back into the oil pan. So it was pooling in the heads and draining down the pushrod holes. When it got below the pushrod holes it was leaking out around the valve cover gaskets.

    I don't know why the shop didn't do anything about that, but I damn sure did.

    I ended up using the dipstick to rod out the oil drain holes and then put the valve cover back on. Then I dumped a gallon of kerosene into the engine, ran it for about 5 minutes and then did an oil change using high detergent oil.

    After about 500 miles I did another oil change with high detergent and resumed my normal oil change schedule. At that next oil change I pulled the valve covers and the heads were clean.

    On a car that's sat like yours and been run very little the past few years, oil gumming up and causing drainage back-ups can be common. Especially if the previous owner used oil with a high parafin content like Quaker State.

    I've seen engines with gum that was like candle wax from Quaker State being run in the engine.

  12. #12
    FEP Senior Member BlackWatch's Avatar
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    Thanks for the help guys. I spent some time today cleaning all of the oily areas and then watched after running the car for 15 minutes. The passenger side valve cover gasket is the culprit. While I was crawling around under the car I cleaned the oil from what I thought was the rear main seal leak and tightened the bolts. They could tighten about a quarter turn. After running the engine the leak appeared high on the passenger side as well. Maybe the oil from the valve covers is finding it's way towards the rear and appearing to look like a rear main seal leak?
    A friend of mine says the shop should have heated the engine up before tightening the bolts on the valve cover. If they didn't do that can a simple tightening stop that leak?

  13. #13

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    Check for a puddle on top of the back of the block where intake manifold seals. If there is a puddle, its the intake manifold. If not, probably valve cover gaskets. if your running any cork gaskets on that car, convert over to rubber. This includes intake manifold, valve cover and oil pan.

    Dont just tighten bolts up. Take it apart, clean up, reseal. Do it right using rubber gaskets

  14. #14
    FEP Senior Member BlackWatch's Avatar
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    I stopped by the garage today and the mechanic tightened the valve cover bolts. Well that made things worse. The valve cover is now leaking towards the rear now, dripping down on the exhaust and puffing smoke. I used cork gaskets, on the advice of a Fox Mustang collector. The driver side gasket is fine but the other side is leaking like a sieve.
    Is this likely a problem with the gasket or did the mechanic screw something up. He said what kkline said above that the rubber ones are better.

  15. #15

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    Moving motor mount= bad
    What did the previous owner do to put the car back on the road after 14 years? If he only did the bare minimum I would check ALL seals and gaskets. If they are the originals they probably dried out and cracked after sitting for so long, that'll cause a leak or two (or 3+)
    Sounds like the mechanic over tightened the valve cover fasteners, that causes the cover to warp and leak. Valve covers don't need to be torqued down too tightly, just enough so the nuts don't come undone.
    Last edited by wrenchwench; 06-29-2012 at 10:44 PM. Reason: add stuff

  16. #16
    FEP Power Member sowaxeman's Avatar
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    Not a fan of the ole' corkies. I replaced all of mine with Felpro reinforced rubber gaskets. No leaks on my cars from the VC's.
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