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HELP: Sprung an Oil leak

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Old 01-16-2023, 07:18 PM
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HELP: Sprung an Oil leak

Well my IROC-Z helped me through most of December, but at a what seems like a major cost! Over the last week or two I've noticed a large oil spot on the ground, and one very ODD random bolt on the ground. After noticing it, I picked up the small bolt, checked the oil and it was in the Add range. I dumped a half quart in to bring her up to op range and started her up. Let her run a bit and after a while... I observed the driver side Exhaust Manifold gasket area visibly wet with oil, but only the #1 Port above SP1? I gave up then, but I went back out today... same big ole oil spot on the ground wet to the touch. Started the car up, let it run a bit & here's the issue I found oil collects on the heat shield right below the exhaust manifold and drips to the ground. (I can get a picture tomorrow). If it matters, this only happened after starting/driving a few times in freezing Ohio weather .

I guess my question is about this random bolt... does anyone have a picture of a stock setup that shows all exhaust manifold bolt holes? Specifically ones that lead into oil passages?
Old 01-17-2023, 08:07 AM
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Re: HELP: Sprung an Oil leak

I don't believe there are any exhaust manifold bolts that go into oil passages. If there are then that is news to me.

It is not uncommon for an engine to leak on a REALLY cold start, like abnormally cold such as we experienced around Christmas. The temps make the oil thick and that results in ridiculous oil pressure on startup and can force some out and wherever the weak spot is (oil filter gasket, pan gasket, etc.)

Are you missing any bolts in the intake? I've seen oil come up and out through the threads of intake bolts before, maybe that's your missing bolt? Or maybe an oil pan bolt wiggled loose?
Old 01-17-2023, 08:18 AM
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Re: HELP: Sprung an Oil leak

Sounds like it was probably this bolt right here.



That hole looks RIGHT DIRECTLY INTO the crankcase. In some blocks, if there's no fuel pump drive rod, you can even see the crank through it. It will leak RUTHLESSLY at cruising speed, but barely any at all at idle. Oil that leaks from it ends up on the crank damper and gets slung as a mist all down the right side of the motor, particularly the bottom of the exh manifold, the motor mount, and the starter.

If that bolt is missing, put a short 3/8" bolt in the hole, with a drop of sealer on the threads.
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Old 01-17-2023, 04:46 PM
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Re: HELP: Sprung an Oil leak

Originally Posted by 92RS-HeritageEd
... I observed the driver side Exhaust Manifold gasket area visibly wet with oil, but only the #1 Port above SP1? I gave up then, but I went back out today... same big ole oil spot on the ground wet to the touch. Started the car up, let it run a bit & here's the issue I found oil collects on the heat shield right below the exhaust manifold and drips to the ground.....
If it's on the driver's side, and above the sparkplug, I don't think it could be the bolt Sofa mentioned. Clear pics of the area on the engine where you see the oil would be most helpful
Old 01-19-2023, 06:03 PM
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Re: HELP: Sprung an Oil leak

Culd it be from the valve cover? Maybe its loose and leaking out.


Old 01-19-2023, 06:15 PM
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Re: HELP: Sprung an Oil leak

I was also thinking valve cover.

To test it, find a secluded area and put your left foot on the brake. Then, put your right foot all the way down on the accelerator until the temp gauge gets to halfway. If the smoke starts coming out the front of the car, open the hood and note its location. Smoke coming from the rear of the car is normal for this test.
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